Summary and Key Features
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Cleansing is the most important step of the skin care routine. Skin cleansing is an important part of maintaining skin hygiene. Simply cleansing the skin with water is not good enough, and selecting the right skin cleanser is key.
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Skin cleansing has evolved and is still evolving. Today cleansing is not limited to basic hygiene. It’s also a part of relaxing. New types of skin cleansers with multiple skin benefits, along with new textures and gestures of skin cleansing, are continuously evolving.
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Selection of cleanser based on skin type is very important to get the desired benefits from the product and maintain the skin barrier function. It’s also important to look for certain ingredients for a particular skin type.
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Cleansing is essential and key for people with different skin disorders. It’s important to follow the process of cleansing to ensure that the skin is in good health and the barrier function is maintained.
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Even though sustainable ingredients are still under development and today there are very few options, eventually sustainability in skin care is expected to grow. Cleansing using sustainable ingredients is the future to maintaining good skin and being respectful to the environment.
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Introduction
The skin is the largest organ in the human body. Maintaining hygiene of oneself and one’s surroundings is essential to prevent illness and disease. Thus skin hygiene involves both cleansing the skin and taking care of its overall health. The primary objective of skin cleansing is to decrease sebum and external pollutants, regulate odors, and manage the skin microbiome. The tradition of cleansing dates back to the beginning of humankind, although the methods have varied over time.
Cleansing has evolved significantly among humans, beyond just removing dirt. It has been a fundamental part of human rituals since the beginning of civilization and continues to play a crucial role in religious ceremonies and beliefs. In modern times, many people view cleansing as a form of relaxation and escape from daily life, as well as a way to enhance the skin’s health and appearance. Regardless of the perspective, it is important to strike a delicate balance between cleansing the skin and preserving its natural balance.
In ancient times, cleansing was performed using bones or stones to scrape the skin. As civilizations developed, materials of plant origin and water were used for cleansing: for example, the Hittites of Asia Minor used a soapwort plant ash solution to clean their hands. Some cultures still use plant-based materials for cleansing today.
Why Do We Need a Cleanser?
Cleansing is a critical aspect of daily life across the animal kingdom, serving mainly as a means of removing dirt and other unwanted substances from the body’s surface. In humans, cleansing has taken on a significance beyond just dirt removal, becoming an integral part of religious ceremony and belief, as well as a form of relaxation and a way to improve skin health and appearance. Simple water is not enough to remove impurities and cosmetic products that are not water soluble, and so skin cleansing is necessary to reduce sebum and external contaminants as well as to control odors and the skin microbiome. Cleansers contain surfactants, such as emulsifiers, detergents, and soaps, that lower surface tension on the skin and remove dirt, sebum, oils from cosmetic products, microorganisms, and exfoliated skin cells. An ideal cleanser should be effective in removing unwanted substances without damaging or irritating the skin and should maintain skin moisture. Cleansing products may contain various surfactants with varying performance to promote normal exfoliation and remove dirt, sweat, and excess sebum from the skin’s surface.
Evolution of Skin Cleansers
The discovery of soap can be traced back thousands of years to civilizations such as the Sumerians, Babylonians, Egyptians, and Romans. The importance of soap as a cleansing agent was recognized in the 1st century AD by Greek physician Galen and by the 8th-century chemist Gabiribne Hayyan. The concept of soap as a luxury item changed in 1791 with the discovery of a cost-effective method of obtaining alkali from sodium chloride by French chemist Nicolas Leblanc. In the mid-1900s, the development of synthetic detergents marked a major breakthrough in the soap market and became the basis of many skin-cleansing products. Today the cleanser market is highly specialized, with cleansers developed for specific skin types and skin concerns. The structure and texture of different body parts also play a role in the development of specialized cleansing products, such as shampoos, conditioners, hand washes, face washes, and body washes.
Chemically, we can define soap as the reaction of a fatty acid and an organic base or an alkali metal to form a carboxylic acid salt. While soap offers a readily available, low-cost means to cleanse and practice effective hygiene, there are drawbacks: for some users, the skin feels tight, sticky, or dry with regular use. This can be dependent on skin type; oily skin types might better appreciate the soap skin finish. Water hardness is also an issue when using soap. Most households have hard water to varying degrees. Hard water is a reference to the calcium and magnesium ions naturally present in water. In combination with soap, they complex to form calcium and magnesium stearate or lime soap. Lime soap tends to build up on sinks and shower surfaces and can be unsightly and challenging to remove. Additionally, because of the formation of lime soap, soap does not foam well in hard water.
In the mid-1900s, we start to see the emergence of synthetic detergents for use in cleansers in the form of a cleansing bar, either alone or in combination with soap, and soon after in the form of a liquid gel cleanser. Synthetic surfactants offered the advantage of leaving a more pleasing skin finish for some users, especially those with dry and sensitive skin types. Additionally, synthetic surfactants do not have the hard-water issues seen with soap. During this period another alternative to soap was developed, a category of cleanser referred to as cold creams. Cold creams are positioned especially for makeup removal. Their mechanism of cleansing is different from surfactant cleansers in that the cleansing active ingredient is oil. The oil provides solvency to soften or emulsify the makeup, which is also oil based. Cold creams are generally water-in-oil emulsions where the oil phase is the external phase.
The soap market continued to expand, and during the Second World War, the development of synthetic detergents came as a major breakthrough. Synthetic detergents now form the basis of most present-day skin-cleansing products. It is to be noted that the structure and texture of the skin on various body parts are different, and hence cleansing needs also evolved based on the application region (e.g., shampoo, conditioner, hand wash, face wash, body wash, intimate wash). By the early 2000s, the cleanser market had become more specialized to meet the growing demand for cleansers developed for specific skin types and skin concerns. This chapter provides a detailed discussion of these specialized cleansing technologies.
Types of Skin Cleansers
Cleansers can be divided into three basic types: soap bars, syndet bars, and liquid cleansers.
Soap Bars
Soap is composed of long chain fatty acid alkali salts with a pH of between 9 and 10. Soap bars are made with the sodium salts of fatty acids, which are a bit harsh compared to the corresponding potassium salts or any other salts of fatty acids. Soap also contains humectants, surfactants, water, moisturizers, binders, lather enhancers, fillers, preservatives, dyes, and pigments.
Soap bars are divided into three main types, based on the composition of the bar.
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Glycerin bars/transparent bars: Made with the sodium salts of fatty acids and a high amount of glycerin. These are generally transparent soap bars. They contain humectant–glycerin to counter the drying effects of soap and hence are comparatively milder than conventional soap bars. These soap bars have a high amount of total fatty matter (TFM).
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Superfatted soaps: Contain a greater amount of lipids such as triglycerides, lanolin, paraffin, stearic acid, or mineral oils, which provide a protective film on the skin. These soaps are also milder than conventional soaps, with high TFM and a comparatively lower pH.
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Combars: Composed of an alkaline soap to which surface active agents with a pH of 9–10 has been added. Combars are milder cleansers than true soaps, but they induce more thorough cleansing than synthetic detergents. Modern-day soap bars are mainly combars. Combars have a lower TFM as compared to true soaps.
Soaps can be drying to certain skin types. To counter this effect, glycerin bars and superfatted soaps were developed, which contain moisturizing ingredients to help prevent dryness and skin irritation. Additionally, the use of gentle surfactants and pH-balancing agents can also help reduce skin irritation and dryness associated with traditional soap bars. However, it is important to keep in mind that skin reactions can vary depending on individual skin type, so it may be best to test different types of soaps to determine which works best for your skin. Box 24.1 shows the typical composition of a soap bar.
| 1 | Soap | Sodium salts of fatty acids (lauric, myristic, palmitic, and stearic) |
| 2 | Water | Solvent for processing |
| 3 | Surfactants | To boost foam (sodium laureth sulfate, cocamidopropyl betaine (CAPB), alpha olefin sulfonates (AOS), polysorbate-20, etc.) |
| 4 | Humectants | For moisturizing effect (glycerin, polyols, glycols) |
| 5 | Binders | Stabilizers (water-soluble fatty acids; fatty alcohols; mono-, di-, or triglycerides; fatty acid esters, particularly fatty acid esters with fatty alcohols; lanolin; petrolatum, etc.) |
| 6 | Lather enhancers | Added in some soaps to enhance lather |
| 7 | Fillers | Hardeners (kaolin, talc, sodium silicate, etc.) |
| 8 | Polymers | To improve processing, bar hardness, and foam stability hydroxypropyl methylcellulose (HPMC), polyvinylpyrrolidone (PVP) styrene copolymer, etc.) |
| 9 | Preservatives | To protect from microbial contamination during shelf life (phenoxyethanol, sodium benzoate) |
| 10 | Fragrance | To mask the base odor |
| 11 | Dyes/Pigments | To impart a particular color |
Syndet Bars
Synthetic detergent bars, commonly known as syndet bars, have a nonsoap synthetic surfactant such as fatty acid isothionates and sulfosuccinic acid esters as their principal ingredients. Synthetic surfactants, unlike soaps, are not manufactured by saponification and their structure is often tailored to impart specific properties to the molecule. Syndet bars are milder than soap bars due to their composition of nonsoap synthetic surfactants that have a neutral or slightly acidic pH; this is unlike soaps, which have a high alkaline pH. They also contain high levels of free fatty acids, which provide a moisturizing effect that helps to maintain skin hydration. Syndet bars are less likely to cause skin irritation or dryness compared to soap bars, and they do not leave behind soap scum. Transmission electron microscopy has demonstrated that skin washed with synthetic detergents has shown well-preserved lipid and protein regions compared to the significant damage to both regions after washing with soap. This confirms that syndet bars show better skin barrier protection as compared to normal soap bars.
Liquid Skin Cleansers
The development of synthetic detergents was a major breakthrough as a mild alternative to soap. Synthetic detergents now form the basis of most of the present-day cleansing products. Despite the many and varied forms skin cleansers can take, they are often referred to generically as soap. Soap, in a strictly chemical sense, is the alkali salt of a fatty acid, most commonly the sodium or potassium salt. Most modern skin-cleansing products are much more complex than the word soap implies. Liquid cleansers may contain a combination of ingredients, including synthetic or natural surfactants, skin-conditioning agents, and other additives such as skin care actives, fragrances, and preservatives. They are formulated to have a pH that is skin friendly, mild, and nonirritating to the skin. Liquid cleansers offer the advantage of being easy to dispense and use and are preferred by many consumers due to their convenience. They are often used as hand wash or body wash and come in various forms such as pump bottles, squeeze tubes, and refillable dispensers.
Liquid cleansers come in different forms, such as body washes, face washes, hand washes, intimate washes, and shampoos, each designed for a specific body part and skin type. They can be made with a combination of syndet and milder soap-based ingredients such as K-soap or TEA-soap or be entirely made of syndet. The pH of the liquid cleansers can vary and may contain skin-conditioning agents and other ingredients to add color and scent, enhance stability, and aid in processing and manufacturing. The growing popularity of liquid cleansers in the market reflects a shift toward milder cleansing options.
In this chapter we will focus on the facial cleansers suitable for different skin types. We will also discuss the skin cleansers recommended for different skin disorders. As such, facial cleansers are the most sensitive product formulations as compared to other cleansers.
Liquid Cleansing Compositions
Cleanser compositions can vary among the multitude of product types within the sector, but these ingredients are transversal to most cleansers: surfactants, humectants, rheology modifiers, exfoliants, active ingredients, preservatives, and emollients. Examples of ingredients in each of these categories can be found in Box 24.2 in table below. It is important to note that the specific ingredients used in a cleanser may vary based on the desired skin benefits, product form, and manufacturer’s formulation strategy.
Surfactants
Surfactants are the principal constituents of most liquid cleansers and are mainly responsible for their cleansing action. Surfactants move to the interface upon dissolving in water and act by lowering the interfacial tension. Surfactants can be ionic, nonionic, and silicone containing. Ionic surfactants based on their polar portions can be anionic (negatively charged), cationic (positively charged), and amphoteric or zwitterionic (both positively and negatively charged, depending on the pH). The type and amount of surfactant in a cleansing product have a bearing on its drying and irritancy potential on skin. Soap is the prototype anionic surfactant used in skin cleansers and plays a prominent role in the personal cleansing market. However, soap quite frequently can cause dryness and irritation of the skin. Cleansers are generally formulated with a blend of two or more surfactants to balance the aesthetic and performance attributes of the product. A liquid cleanser generally contains a mix of anionic, nonionic, and zwitterionic surfactants to address the overall foaming and cleaning experience.
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The primary surfactant of a cleanser is usually anionic, as they are the most versatile in terms of their detergency, foaming, and oil solubilization. An anionic surfactant is responsible for providing a high amount of foam and better cleansing. A subcategory of anionic surfactants is amino acid–based surfactants. These have gained popularity due to their mildness and soft, conditioning skin finish.
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Amphoteric or zwitterionic surfactants are used for their excellent foam boosting and conditioning effect, and in some cases will contribute to building viscosity in the product. These surfactants act as cosurfactants, interacting with the anionic surfactants in the cleanser.
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Nonionic surfactants are generally low foaming or nonfoaming and more specialized in their use. For example, polyglyceryl esters are especially useful in oil cleansers for their emulsifying properties, and alkyl polyglucosides are often used in natural origin cleansers. Nonionic surfactants are used to solubilize different actives and fragrances before being added to the cleansers. Nonionic surfactants are great emulsifiers and are the mildest of all types of surfactants.
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Cationic surfactants are not used for cleansing but, because of their positive charge, are substantive to the skin and make good skin conditioners in a cleanser. Some of the cationic surfactants help deposit active ingredients on the skin. Some also show strong antimicrobial properties and therefore are used as preservatives or as skin disinfectants. Box 24.2 shows some examples of surfactants and their intended benefits.
Box 24.2
Different Types of Surfactants Used in Cleansers
Anionic Surfactant
Amphoteric Surfactant
Nonionic Surfactant
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Soap
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K or TEA salts of fatty acids
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Ethoxylated alkyl sulfates
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Sodium laureth sulfate
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Ammonium laureth sulfate
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Amino acid based
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Disodium or sodium cocoyl glutamate
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Sodium lauryl sarcosinate
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Sodium cocoyl methyl taurate
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Sodium cocoyl glycinate
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Isethionate
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Sodium cocoyl isethionate
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Coco-betaine
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Cocamidopropyl betaine
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Sodium or disodium cocoamphodiacetate
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Cocamidopropyl hydroxysultaine
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Alkyl polyglucosides
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Decyl glucoside
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Coco glucoside
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Lauryl glucoside
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Polyglyceryl ester of fatty acids
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Polyglyceryl-3 caprylate
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Polyglyceryl-2 oleate
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Polyglyceryl-6 dicaprate
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Sorbitan esters
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Polysorbate 20
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Polysorbate 60
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Polysorbate 80
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Pentylene glycol-hydrogenated oil
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Pentylene glycol-40 hydrogenated castor oil
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Humectants
Long-chain alcohol and polyols are used as humectants in cleanser formulations. The most often used humectant in cleansers is glycerin. Humectants help hydrate the skin and pull moisture to the skin’s surface. Humectants will also provide a soothing feel to the skin on dry-down after cleansing and maintain skin health and the natural moisturizing factor (NMF). Box 24.3 lists some humectants typically used in cleansing products.
Emollients
Generally thought of as an ingredient in a leave-on product rather than a cleanser, emollients have gained usage in cleansers with the growth of the oil cleanser category for makeup removal. As mentioned, oils provide solvency to the makeup for easy removal, and most emollients are well tolerated. Both synthetic and natural oils are used as emollients to reduce the negative effect of surfactants on the skin. Emollients keep the skin soft and supple and provide smoothness to the skin. Box 24.4 provides some examples of humectants commonly used in cleansers.
| Emollients |
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Rheology Modifiers
Rheology modifiers help build viscosity, boost, and stabilize foam. Cleansers that contain sodium laureth sulfate (SLS) may not need a polymer as a rheology modifier, since they build viscosity in the presence of any electrolyte such as sodium chloride or potassium chloride. Some amphoteric surfactants can also build viscosity with sodium chloride. In the presence of electrolytes, the micellar structure of the surfactant system changes, which helps build up viscosity. If a surfactant system cannot build viscosity with sodium chloride, a polymer-based rheology modifier is needed. Generally, hydrophobically modified polymers, natural gums, and cellulose are used as rheology modifiers. They also act as conditioning agents and work as a deposition aid to deposit different skin care ingredients through cleansers. Rheology modifiers can also provide a unique texture to the product. Some polymers also help give a creamy and stable foam in a cleanser. Rheology modifiers also provide a good postwash feel and keep the skin soft and smooth. Some of the viscosity modifiers, such as acrylate copolymer, help build a structural network within the cleanser, which also helps keep any solid substances suspended within the cleanser and doesn’t allow them to settle down. These are generally used to give a great aesthetic to the product. They also help keep the encapsulated fragrance or actives suspended within the system. Box 24.5 shows some examples of viscosity modifiers generally used in cleansers.
| Rheology Modifiers |
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Skin Types and Cleansing of Specific Skin Types
Broadly, skin types are categorized into five types.
Oily Skin
There are a variety of factors that can lead to oily skin. Genetics is a common one, since many people are simply born with more active sebaceous glands. These glands are also more active during one’s younger years, as the skin will tend to become less oily with age. Climate can also play a role in how oily the skin is. For example, a hotter, more humid area will naturally lead to shinier skin. It’s also possible to develop oilier skin when using the wrong skin care products. Heavier products often result in excess shine, so it’s best to use lightweight, oil-free products to minimize potential greasiness. This skin type requires extra attention. By using a face wash specifically designed to get excess oil under control each morning, the skin will need less maintenance throughout the day. In addition to these factors, hormonal changes such as during puberty, menstruation, pregnancy, and menopause can also cause an increase in oil production. The use of certain medications such as hormone replacement therapy and birth control pills can also impact sebum production. Poor diet and lack of hydration can also contribute to oily skin. It is important to maintain a balanced diet and drink plenty of water to keep the skin healthy. Additionally, using gentle and noncomedogenic skin care products and avoiding heavy makeup can help minimize the appearance of oily skin.
The cleansing step is one of the most important parts of the daily routine, since a cleanser for oily and acne-prone skin can help rebalance the skin. When someone has oily and acne-prone skin, they really need to address two issues. First, the acne cleanser should have ingredients such as salicylic acid or benzoyl peroxide. The cleanser should also contain ingredients to replenish some healthy, water-trapping ingredients, such as ceramides, lipids, coconut oil, and aloe vera, to make up for the dehydration commonly seen in oily, acne-prone skin. One of the things that can be counterproductive to oily skin is applying oils. People with oily skin should avoid products that contain shea butter and coconut oil; avoid overly astringent products such as those with a high alcohol content or high concentration of tea tree oil; and avoid scrubbing the skin aggressively, particularly with products that have jagged particles such as apricot pits, pumice, or jojoba beads. However, there are other ways to protect the barrier of an oily skin type, including cleansing with a gentle cleanser, opting for a gentle topical retinoid to help normalize oil production, and trying products with salicylic acid as its lipophilic derivatives are quite effective in managing oily skin. A key distinction in taking care of oily skin is to understand the difference between hydration and moisture in skin care. Oily skin may not require much moisture but definitely needs to be well hydrated to maintain the skin barrier and skin health. Topical hydrators such as glycerin and hyaluronic acid bind water to the skin, and there are many water-based formulas that are well suited to oily skin. Mild gel cleansers with light textures and containing acids such as glycolic, salicylic, azelaic, mandelic, and lactic acids are also quite useful and help exfoliate the skin. The product should preferably contain some antiinflammatory ingredients such as niacinamide, aloe vera, witch hazel, calendula, and chamomile to provide the extremely necessary soothing benefits to such a skin. Other ingredients such as zinc oxide and benzoyl peroxide are also useful and recommended.
Dry Skin
Dry skin requires a different approach to cleansing compared to oily skin. People with dry skin need to be mindful of the impact that cleansing has on their skin’s barrier function. Cleansing, even with just water, can deplete the skin’s NMF and lipids, which can be a concern for people with dry skin who already have a weakened barrier. To protect the skin’s barrier, it is important to choose a hydrating cleanser. A cleanser that both hydrates and cleanses is essential, especially during cold weather when dryness and irritation can worsen. By choosing a hydrating formula, the skin’s barrier will feel calm and hydrated, and the skin will be better able to absorb the other skin care products that are applied afterward.
Cleansers and face washes come in a variety of textures, from oils to gels, milks, powders, and balms. Micellar waters are a great choice for dry skin. While most are fine for dry skin, gel cleansers or cleansing balms are preferred. The best ones have ultragentle surfactants that remove makeup, oil, and grime with minimal disturbance of the skin’s protein and lipid barrier and maintain the skin’s NMF. As well as the texture, it is equally important to pay attention to what’s in the formula to soothe dry skin. People with dry skin are recommended to avoid cleansers with fragrance and essential oils, which can trigger irritation and sensitivity in sensitive skin. Instead, look for products with hydrators such as humectants (glycerin, polyols, hyaluronic acid, aloe vera, vitamin B5, ceramides) and conditioning ingredients (peptides, oatmeal, natural oils, lipids, vitamin E, triglycerides, milk cream), as these will help soothe and moisturize a parched complexion. Natural or synthetic oils are also quite useful and are good emollients. It’s also important to avoid hot water, as this can also leach away skin lipids.
Normal Skin
Normal is a term widely used to refer to well-balanced skin. The scientific term for well-balanced skin is eudermic . The T-zone (forehead, chin, and nose) may be a bit oily, but overall sebum and moisture are balanced and the skin is neither too oily nor too dry. Normal skin can handle most types of cleansers, from gel to foam to milk, but it’s important to choose a formula that works for a particular skin type. Avoiding cleansers with ingredients that can strip NMF of the skin, such as alcohol, is recommended. It’s important to opt for a mild formula that contains gentle surfactants and moisturizing ingredients such as glycerin, hyaluronic acid, aloe vera, and ceramide. It’s also important to avoid using very hot water, as this can dehydrate the skin. A balanced skin care routine that includes regular cleansing and hydration can help maintain the skin’s healthy state and prevent future skin problems.
For people with normal skin, using a gentle, everyday cleanser is the best choice. Gels are a popular option, as they are suitable for all skin types. However, use of hard water makes the skin very dry and flaky. A creamy or balm cleanser may be more appropriate, as it can be wiped off without water. Cleansing frequency depends on various factors, such as the time of day and climate. Washing the face twice daily is recommended, but if the skin becomes dry, adjusting the routine as per the skin’s need is crucial. In general, a deep cleaning at the end of the day is recommended, while in the morning a mild cleanser is recommended to maintain the skin’s balance.
Combination Skin
This skin type features two or more different skin types on the face, and the condition of the skin may fluctuate between seasons. Typically, the combination skin type is characterized by dry, flaking skin on the cheeks while excessive oil and shine appear on other areas of the face. When the skin has just one problem, such as excess oil production or dry patches, it’s easy to figure out which products work best, whereas a combination of both oily and dry skin makes skin cleansing more challenging. Not all cleansers will work for combination skin because the skin needs a sophisticated balance. For combination skin, it is important to choose a gentle cleanser that effectively removes makeup, sunscreen, and dirt while not overdrying the skin. It’s recommended to choose a fragrance-free formula and to consider using enzyme-based cleansers or cleansers containing salicylic acid, as they are gentle yet effective in thoroughly cleansing the skin and breaking up sebum in pores without being drying. The best cleanser should balance oil production in the T-zone and leave the skin feeling fresh and hydrated.
It’s important to avoid harsh ingredients in the cleanser for combination skin, as they can strip the skin of its natural oils, causing the skin to produce even more oil, which can lead to imbalanced skin. Harsh ingredients can also cause tightness and flaking in the dry areas of the face. Instead, it’s important to choose a gentle, balanced formula that removes impurities. This will help effectively cleanse the skin while keeping it hydrated and fresh.
Sensitive Skin
Sensitive skin is defined as a sensory reaction triggered by contactors and/or environmental factors, usually without a visible clinical manifestation. Sensitive skin is a condition characterized by stinging, burning, and itching sensations. The diagnosis, pathophysiology, and treatment of sensitive skin are still evolving. Low temperature, humidity, wind, heat, and sun exposure favor the manifestation of sensitive skin. Pollution, common in the industrialized world, has been one of the factors responsible for this entity. Sensations described by patients vary largely and include pruritus, burning, tingling, pungency, thickening, or dryness of the skin. These symptoms may occur minutes to hours after contact with a cosmetic product/environmental stimulant, or even after several episodes of use of a topical product, triggering the conduction by cumulative effect.
Sensitive skin requires extra care and attention when choosing a cleanser. It is better to avoid cleansers that contain ingredients such as alcohol, fragrances, parabens, silicones, and sulfates and instead to opt for gentle, fragrance-free, and noncomedogenic formulas that are designed for sensitive skin. It’s also helpful to look for cleansers that contain soothing ingredients such as chamomile, aloe vera, and green tea, which can help reduce redness and calm the skin. Additionally, using lukewarm water instead of hot water and being gentle when cleansing can help prevent irritation. It’s also important to patch test new products before using them all over the face to ensure that they don’t cause a reaction.
When it comes to cleansing for sensitive skin, it’s important to choose a gentle, fragrance-free formula. Avoiding harsh ingredients, as well as products with high concentrations of alcohol or fragrances, which can irritate the skin and trigger symptoms, is key. A gentle cleanser, such as a micellar water, cream, or milk formula, is best for sensitive skin. Enzyme cleansers can also be effective, as they gently remove impurities without causing irritation. Additionally, products containing soothing ingredients such as chamomile, green tea, or aloe vera can help calm and hydrate sensitive skin. Proper hydration of the skin is also important for individuals with sensitive skin, so using a moisturizer after cleansing can help improve symptoms.
Cleansing of Other Skin Types
Cleansing of Baby Skin
Baby cleansing is important for hygiene, but water alone is insufficient. Additionally, baby skin is still developing and different from adult skin and hence needs special care. Cleansing infants is critical for both infant and family hygiene. Microbial colonization occurs shortly after birth, and a baby’s proclivity to be in contact with many substances is well known. Cleansing removes unwanted surface material and can prevent infection, ingestion, and transmission of microbes and matter on the surface of the skin. In addition to the hygiene benefits, regular bathing also provides necessary skin care for baby skin.
Baby skin continues to mature during the first years of life and thus requires milder, gentler cleansing than adult skin. While cleansing with water alone is insufficient, typical adult cleansers are also inappropriate for baby skin, since their surfactant systems are too aggressive and would be harsh for the skin. In addition to containing less total surfactant, baby cleanser surfactant blends create larger micelles and result in less aggressive, albeit lower-foaming, systems. The formulator’s challenge is to design aesthetically desirable baby cleansers without compromising the critical requirements of mildness and skin compatibility. This trade-off between mildness and performance is not limited to baby cleansing, but rather is present across the cleansing category; many consumers (e.g., individuals with sensitive skin, eczema, or atopic dermatitis [AD]) may also benefit from cleansers with increased skin compatibility. There are two current developments in mild baby cleansing that are worth noting. First, cleansers are increasingly being formulated with surfactants that are partially derived from renewable sources, as opposed to petroleum. Commonly, plant oils are chemically modified with a polar group to create these natural surfactants. While not inherently milder, natural surfactants suffer the same trade-off between mildness and performance; however, they do broaden the palette available to formulators. Second, recent technical advances in the understanding of surfactant tissue interactions have led to the use of hydrophobically modified polymers (HMPs) to create cleansers with improved mildness. It has been shown that polymer-surfactant association with HMPs is a practical method for effectively reducing the free micelle concentration and thereby reducing the aggressiveness of the cleansers. The addition of HMPs to cleansing systems allows the formulator to attain new levels of skin compatibility for enhanced consumer benefits. Please refer to “Effect of Skin Cleansers on Skin Barrier Properties” for formulation details of such products.
It is recommended to use skin cleansers targeted for babies or to consult a dermatologist for advice on choosing the best baby cleanser for baby’s skin type, as different babies may have different skin needs. The dermatologist can also advise on adjusting the cleansing regimen to best suit the baby’s needs and help achieve optimal results with therapy.
Cleansing of Aged Skin
As the world’s population grows and ages, the number of people over the age of 80 is increasing, bringing with it changes in the skin that come with the aging process. Aging is associated with structural and functional changes of the skin that result in increased vulnerability. These changes, including a decrease in cell replacement, compromised barrier function, and reduced moisture content in the skin, can lead to dermatologic disorders and skin injuries. Chronic diseases, drugs, and environmental factors, including poor skin care habits, can also damage the skin’s barrier function in the elderly. In Evolution of Cleansers Into the Cosmeceuticals Space and Cleansing of Compromised Skin, we discuss the importance of proper cleansing for different skin disorders, including those in aging skin.
Skin-cleansing products containing anionic or amphoteric surfactants compared with standard soap-and-water washing improve skin dryness and demonstrated skin protecting effects. Moisturizers containing humectants consistently show statistically significant improvements in skin dryness. Skin barrier products containing occlusives reduce the occurrence of skin injuries compared with standard or no treatment. Using low‐irritating cleansing products and humectant‐ or occlusive‐containing moisturizers seems to be the best strategy for maintaining the skin barrier function and integrity for aged skin.
Cleansing of Wounded Skin
Wound cleansing has been an important aspect of wound care for a long time, with a history rooted in both tradition and science. It is a crucial step in the management of acute and chronic wounds and helps reduce the risk of infection. It is generally believed that all wounds should undergo some form of cleansing to reduce the bacterial load and improve the chances of successful healing.
Wound care has evolved to a science that focuses on not only controlling bacterial contamination but also promoting the wound healing process. The goal of wound management is to balance the reduction of microbial contamination with minimal injury to the wound tissue. Topical antiseptics, such as topical antimicrobial agents, play a crucial role in controlling infection in wounds. The quality of care provided to the wound is critical in promoting healing, and the use of topical antiseptics should be balanced with promoting healthy granulation tissue and the healing process. The use of topical antiseptics should be guided by the principles of wound healing and optimized to promote the best possible outcome.
Several antiseptic categories exist, including alcohols (ethanol, isopropyl alcohol), anilides (triclocarban), biguanides (chlorhexidine), bisphenols (triclosan), chlorine compounds, iodine compounds, zinc oxide compounds, silver compounds, peroxygens, and quaternary ammonium compounds. The most commonly used products in clinical practice today include povidone-iodine, chlorhexidine, alcohol, acetate, hydrogen peroxide (H 2 O 2 ), boric acid, silver nitrate, silver sulfadiazine, and sodium hypochlorite. Although acetate (a radical) and silver sulphadiazine (an antibiotic) as well as other products are not really antiseptics, they are listed in several reports discussing topical preparations for wound care, therefore creating some confusion in the classification of topical disinfectants, antiseptics, and antibiotics.
Choosing the Right Type of Facial Cleanser
Cleansing might not be the most exciting part of one’s skincare routine, but when you consider the amount of pollution, sweat, and dirt that can accumulate throughout the day, it’s easy to see why it’s such an essential step. With so many cleansing options available, it’s easy to feel a little overwhelmed. Knowing the difference between each type can help determine the suitable options for a particular skin type and make the lookout for the right cleanser a lot easier. This section discusses some widely available cleansers. It’s important to choose a cleanser that is appropriate for your skin type, as using the wrong type of cleanser can cause dryness, irritation, or breakouts. It’s always best to patch test new products before incorporating them into the skin care routine, and to avoid using harsh ingredients.
Gel Cleanser
Gel cleansers are clear and, as the name suggests, have a gel-like consistency. Generally designed for deep cleansing, they are effective at decongesting clogged pores and removing excess oil. Gel cleansers containing alpha-hydroxy acid (AHA; e.g., glycolic acid) and beta-hydroxy acid (BHA; e.g., salicylic acid) are generally recommended for acne or oily skin; are perfect for providing a lightweight cleanser; and are suitable for normal, combination, or oily skin and skin that is sensitive to redness. Fragrance-free, paraben-free, and sulfate-free gel cleansers provide deep cleaning that is gentle enough for even the most sensitive skin yet, due to their unique ingredients and formulation, are perfectly able to deep clean oily, acneic pores and blemishes without causing dryness, irritation, or inflammation and without stripping the protective acid mantle.
Foam Cleanser (Autofoam)
The autofoam cleansers are dispensed as a foam due to their unique packaging, which helps create the foam. There is another type of autofoam cleanser that is more or less in between gel and cream cleansers, which makes it great for combination skin types. It starts out as a cream or gel and bursts into a rich, foamy lather. These cleansers are travel friendly and easy to rinse, and they remove excess oil as effectively as gel cleansers. These products are very mild and suitable for sensitive skin.
Cream Cleanser
Just like gel cleansers, cream cleansers are pretty much exactly what they sound like. They are very creamy and lush in texture. Cream cleansers tend to be gentler and more hydrating than other cleansers, making them ideal for dry or sensitive skin types. They work hard to gently cleanse the skin without stripping it of its natural oils. They also make a great second-step cleanser for people who are into double cleansing.
Cleansing Oil
The concept of putting more oil on oily skin may not make sense, but these cleansers usually contain an oil base to help remove dirt on the skin without interfering with the skin barrier. The oil from the skin works together with the cleanser to balance the skin. An oil cleanser is a gentle way of removing pore-clogging debris, including waterproof makeup, without drying the skin. Cleansing oil is perfect for removing oil-based and heavily pigmented products from the skin (such as heavier foundations) and suitable for drier, mature skin types. Cleansing oil provides a deep clean that breaks down and removes excess oil, makeup, sunscreen, and environmental impurities while nourishing argan, moringa, and olive oils help deliver key nutrients and antioxidants to keep skin clear and radiant.
Clay Cleanser
Natural clays have been used to heal skin infections since the earliest recorded history. A clay cleanser is a type of cleanser that uses clay as one of its main ingredients to clean the face and remove other impurities from the skin. It is one of the most popular types of cleansers in the beauty industry today. Generally, cationic clays are used in clay cleansers, and thereby these cleansers also show strong antibacterial properties. These cleansers can also be used as masks. They absorb all impurities and detoxify the skin. Typical clay cleansers don’t foam as much as gel cleansers. They work to remove excess oil and dirt from the skin, which can help minimize the appearance of pores, reduce blemishes, and create a more mattified complexion. Needless to say, clay facial cleansers can be beneficial regardless of skin type, as they are very mild and made of natural clays. Clay cleansers are an ideal middle ground if someone is wary of putting oil onto skin but does not want to risk water-based cleansers being too harsh. They are made with mineral-rich clays, which draw dirt and bacteria from the skin, leaving the face feeling squeaky clean when washed off. They are great for deep cleansing, and there are various types to suit specific skin types.
Powder Cleanser
Cleansing powders are concentrated versions of liquid cleansers that form a paste or foam when activated with water. Most contain naturally derived ingredients such as rice bran, oats, and adzuki beans to give the product gentle, nonabrasive exfoliating properties, making it perfect for those with sensitive skin. To get the ideal low-foaming lather, the amount of water must be adjusted while rubbing a coin-sized amount of the cleanser between the hands, with more water added to the cleansing powder for milder cleansing. Cleansing powders are ideal for travel, and they typically contain fewer preservatives than liquid products since there’s no water in the formula.
Cleansing Balm
Cleansing balms fall under the same formulation as an ointment. They have a higher lipid-to-water ratio, which means they’re richer and thicker in consistency compared to your average cleanser. Often formulated with hydrating oils and waxes, cleansing balms are masterful at melting away stubborn makeup (sunscreens and mascara included), and will deeply cleanse the skin of impurities without leaching away its natural sebum. They are super hydrating and won’t create that notorious tightening effect, even on oily skin types. A great aspect of cleansing balms is that they’re effective on all skin types, especially dry and dehydrated skin. As cleansing balms are formulated with higher levels of nourishing ingredients such as fatty acids, fatty esters, natural oil, and vitamins, they are great at cleansing the skin without making it feel dry or stripped. Therefore autumn and winter can be great times to introduce a cleansing balm into the skin care routine. Cleansing balms are not only great for dry skin; they are also great mollifiers for sensitive or reactive complexions. Cleansing balms often contain skin care ingredients such as hyaluronic acid, collagen, ceramides, and vitamin E, which soothe conditions such as eczema and psoriasis. Most cleansing balms start as a solid but emulsify into an oil with shear during application on the skin, and finally emulsify in contact with water. Cleansing balms are ideal for double cleansing, that is, using a balm first to remove oil-based impurities before following up with a nondrying cleanser to banish any leftover residue. Cleansing balms can be massaged directly onto wet or dry skin, depending on preference. Use lukewarm water to remove the balm and follow up with the rest of the skin care routine.
Micellar Cleansing Water
Micellar water has been touted as the latest all-in-one product that minimizes skin irritation, making it a new must-have for those with sensitive skin. Interestingly, however, micellar water is not new and is suitable for all skin types. In fact, micellar water has been around for over 100 years. Developed in France as a gentle yet powerful alternative to that country’s harsh water supply, it now has a cult following. Micellar cleansing water is a facial cleanser and makeup remover that is surprisingly powerful yet gentle on the skin. The micellar water for all skin types effectively cleanses, removes makeup, and refreshes the skin. Working like a magnet, micelles capture and lift away dirt, oil, and makeup without requiring harsh rubbing. The micellar water for normal skin cleanses to remove makeup and leaves the skin with a matte and natural finish, with no greasy residue. It may look like water and have the same viscosity as water, but the texture of the micellar variety is much different. Micellar water draws out skin impurities without drying out the skin. Therefore it can be used as a makeup remover and mild cleanser. It also doesn’t require water to work, nor does it need to be rinsed off afterward. And because it’s so gentle and hydrating, micellar water seems perfect for those with dry and/or sensitive skin. It doesn’t contain any harsh chemicals, so it won’t strip skin of natural or “good” oils needed to stay hydrated and balanced. In fact, if micellar water is used properly and not rinsed off after use, the skin won’t be exposed to potentially harsh tap water minerals and trace chemicals that can mess with pH levels. Micellar water can be monophase or biphasic. Biphasic micellar water, which contains oil, is a stronger makeup remover and can remove all kinds of makeup effectively.
Micellar Biphase Cleansing Water
Oil-based cleansers are also gentler on the skin because they leave the natural oil layer on top of the skin, so for sensitive and rosacea-prone skin, there is minimal irritation. This type of cleanser works best on waterproof makeup. Oil-based products rarely create foams and clean all kinds of long-lasting makeup thoroughly. For oily skin, it’s best to have a cleanser with less oil, so micellar water or other water-based cleansers are recommended. Applying an oil-based product to an already oily complexion could result in congestion or breakouts, as the skin simply does not need the extra oil. As a general guide, choose water-based cleansers for oily skin that do not leave an oily residue on the skin. Water-based products are best for oily, acne-prone, and sensitive skin because they wash away excess oil and don’t add oiliness to the skin. However, dry skin can benefit from oil-based cleansers, as they help replenish the skin’s natural oils. If the skin is really dry, an oil-based cleanser is recommended to help repair the integrity of the skin. Oil-based cleansers help replace the lipids dry skin loses. Oil-based cleansers with nourishing ingredients, such as vitamin E, vitamin A, retinol, avocado, jojoba, rosehip, and essential fatty acids, are highly recommended to maintain the skin barrier function.
Cleansing Wipes
Facial wipes are saturated towelettes that give the face and hands a quick clean when on the move or for quick sanitization. These help in removing excess grime and sebum, giving the face a refreshed feel. However, there are many more uses of facial wipes. The main intent of facial wipes or makeup wipes is to remove makeup in a few easy swipes. Makeup wipes are single-use cloths soaked with facial cleanser and/or makeup remover to rid skin of the day’s beauty products as well as any remnants of dirt or debris. These are not only travel friendly but easy and convenient to use. They are formulated to gently break down makeup or residual grime and dirt without being overly stripping. The plant-based wipes are biodegradable and mild for skin. They come in many formulas, catering to different needs such as keeping hands clean or instantly giving a cooling sensation when it’s hot and sticky outdoors. In the beauty space, facial wipes play a slightly different but effective role. Makeup wipes are often more affordable than traditional cleansers and are considered to be all-around convenient.
No-Rinse Cleanser
No-rinse cleansers leave skin clean, refreshed, and odor free with no water necessary. The solution is ready to use out of the bottle. The gentle formula eliminates odors and moisturizes as it cleans. Apply the solution to the face and body, massage to lather, and the gentle solution cleans and refreshes. Some cleansers are pH balanced and safe for sensitive skin and can be used as a perineal cleanser. The major ingredient is water and ultramild surfactants along with some skin care ingredients. In general, these products are mild and free of alcohol and silicone and hence are suitable for sensitive skin. They do not irritate skin, so they are safe for adults and children of all skin types. These are also travel friendly.
Facial Scrub Cleanser
Slough away dull skin and dead skin cells with chemical and physical exfoliators that are gentle yet effective for every skin type, as recommended by dermatologists. Exfoliators are a somewhat essential product needed for glowing skin. Chemical exfoliators are ingredients that help loosen the bonds between dead skin cells, allowing them to shed and reveal newer and healthier cells beneath. They also help unclog pores and exfoliate away surface skin cells; in addition, they brighten skin and improve skin cell turnover and renewal, and some may even help stimulate collagen production within the skin. The resurfaced skin helps the subsequent skin care products sink in more effectively and provide a better result. However, despite the benefits of using an exfoliator, overuse can lead to redness, irritation, breakouts, and damage of the skin barrier function. Additionally, using an exfoliator that’s either too harsh or too gentle for a particular skin type can disrupt the luminous skin finish. To strike an optimal balance, it’s important not to use an exfoliator too often, essentially no more than two to three times per week. For dry or sensitive skin, one to two times per week should be good enough. Dermatologists recommend exfoliating with a physical exfoliator for about 30 seconds (or less) using small, gentle, circular motions. For chemical exfoliators, the instructions printed on the packaging should be followed, as they can vary by product. It’s also important to use a formula that contains the best exfoliants for the particular skin type. Mechanical exfoliators are not recommended for sensitive skin; instead, use of chemical exfoliators such as AHAs like glycolic acid, lactic acid, and azelaic acid are recommended. These acids exfoliate the upper layers of the skin while also hydrating and helping the skin retain moisture. Polyhydroxy acids, or lactic acid and mandelic acid, which are larger alpha-hydroxy acid molecules that do not penetrate as deep into the skin and are least likely to cause irritation, are recommended for sensitive skin. On the other hand, physical exfoliation is key for oily skin, since it helps remove any layers of oil buildup. For oily skin, the dead skin cells are more adherent and don’t flake off as quickly, and this can contribute to breakouts. Hence it’s recommended to use an exfoliating scrub with AHA or BHA, which gently peels off and speeds up skin turnover as well as better penetrates oil and oily follicles to keep skin clean and clear of blemishes. Salicylic acid is also excellent at targeting oil and unclogging pores. Another interesting ingredient is gluconolactone or polyhydroxy acid (PHA). This is milder than both AHA and BHA.
Cleansing Milk/Lotion
Perfect for dry, sensitive skin types but suitable for all skin types, cleansing milk/lotion is a good choice as a double cleanser. These are gentle cleansers containing the ceramides or any components of the NMF components, which closely match the natural structure and composition of healthy skin. They provide protection and care for the skin and will not disturb the pH of the skin. These cleansers are also free of preservatives, mineral oils, perfumes, dyes, amines, SLS, silicones, and emulsifiers.
Nonfoaming Cleansers
These contain fatty alcohols and are suitable for people with sensitive or dry skin. They can be wiped off without water. The fatty alcohols in these lotions facilitate evaporation, so rinsability is high. When used on the face, there is less facial residue, which is an advantage of these lipid-free cleansing lotions. These agents also contain emollients (e.g., fatty alcohols) and/or humectants (e.g., propylene glycol, butylene glycol, hexylene glycol, sorbitol), which counter the irritancy or drying potential of the surfactant.
Effect of Skin Cleansers on Skin Barrier Properties
The stratum corneum (SC) is the top layer of the skin’s epidermis and is the skin’s protective barrier. It is made up of corneocytes (dead skin cells) and a lipid-rich matrix that contains ceramides, cholesterol, and fatty acids. The SC is usually described as a “bricks and mortar” structure in which the protein-enriched, flattened corneocytes (dead keratinocytes lacking vital cellular organelles) are the “bricks” and the lipid-rich matrix in which they are embedded is the “mortar.” This lipid matrix predominantly contains ceramides (40–50%), cholesterol (25%), and free fatty acids (10–15%). The SC lipids spontaneously and in an orderly manner form multiple bilayers that interact with corneocyte envelope–bound lipids. In deeper layers of the SC, lipids are predominantly ordered into a densely packed orthorhombic crystalline configuration, which acts as a restrictive barrier to liquid transport. Closer to the SC surface, the lipids form a dispersed hexagonal lattice configuration that permits more liquid to pass through more freely. The highly ordered lipid structure in the SC regulates water content and prevents excessive transepidermal water loss (TEWL). The SC is constantly functioning to maintain its water content, regulates water flux, and modifies the rate and magnitude of TEWL. Such mechanisms are highly dynamic and function continuously to maintain homeostasis of the SC, the epidermis, and the skin in its entirety. As such, the SC is a robust factory that is in operation at all times, ensuring the maintenance of the skin’s adaptive and protective barrier. However, harsh cleansers can damage the SC proteins, lipids, and NMF components, so it’s important to use gentle cleansers that don’t impair the skin barrier. Maintaining the skin’s cleanliness is crucial to preserving its barrier properties for all skin types. It is generally recognized that all types of skin, from healthy to diseased, infant to aged, need to be kept clean to preserve their barrier properties.
Factors Causing Dryness and Irritation in Cleansers
Harsh surfactants can cause irritation, leading to symptoms such as dryness, redness, itching, and burning. To minimize these effects, it’s recommended to choose mild, pH-balanced cleansers that are free of harsh ingredients. Furthermore, it is important to consider the individual’s skin type, personal preferences, and other factors such as skin condition, climate, and frequency of use when choosing a cleanser. In general, it’s recommended to use gentle, fragrance-free, and nonirritating cleansers, especially for people with sensitive skin. Additionally, using a moisturizer after cleansing can help restore the skin’s natural barrier and hydration levels.
Harsh surfactants can result in the degradation of the skin barrier function over time. This is why it is important to choose cleansers that are gentle and nonirritating, and to avoid alkaline soaps that can strip the skin of its natural lipids and moisturizing factors. The use of HMPs in cleansing formulations has been shown to mitigate the adverse effects of surfactants on the skin barrier by enabling the formation of larger, more stable surfactant structures that are less likely to penetrate the skin. Additionally, the type and rinsability of surfactant ingredients, as well as the pH of the cleansing product, can also impact the skin barrier function and should be considered when selecting a suitable cleanser.
Surfactant-induced skin irritation and barrier disruption are not solely due to surfactant monomers but also involve other factors such as surfactant concentration, micelle formation, and their interaction with the skin barrier. The current understanding of skin–surfactant interaction is more complex and multifactorial. In addition to the concentration of surfactant monomers, the size, shape, and hydration state of surfactant micelles and the presence of cosurfactants can affect the skin irritation potential of surfactant formulations. To minimize surfactant interaction with skin, it is important to choose surfactant systems that not only are mild but also respect the natural composition and structure of the skin barrier. The use of HMPs in cleansing formulations can help create skin-compatible cleansing systems by assembling surfactants into larger, more stable structures that are less likely to penetrate the skin and more likely to maintain the integrity of the skin barrier.
This has led to the development of new strategies for creating skin-compatible cleansing formulations that consider the potential for surfactant micelles to penetrate the skin. One approach is the use of HMPs, which, when present in a cleansing formulation, help assemble surfactants into larger, more stable structures. These structures are less likely to penetrate the skin and thus result in gentler, less aggressive cleansers. Another approach is to alter the solution properties of surfactants to minimize their interaction with skin, such as by using surfactants with low critical micellar concentrations (CMCs). However, it is important to note that the CMC is not the sole determining factor in skin irritation and penetration, and a more holistic approach considering all factors affecting surfactant behavior is needed.
pH
The pH of the cleansing agent can also affect the irritancy potential of the product. Cleansers with pH close to skin pH (∼4.5–5.5) are considered to be less irritating than those with highly acidic or alkaline pH (<4.0 or >7.0). An extremely low or high pH can disrupt the acidic mantle of the skin and affect the barrier function, whereas an alkaline pH can lead to denaturation of proteins and skin irritation. Hence it is important to maintain a neutral pH in cleansing agents to minimize skin irritation.
Rinsability
Rinsability of the cleansing agents is another important factor that determines its irritancy potential. Poorly rinsed cleansing agents can leave residues on the skin, leading to skin irritation and dryness. To improve rinsability, ingredients such as polyethylene glycol (PEG) and polyvinyl alcohol (PVA) can be added to the cleansing formulation. Cleansers should be properly washed off from the skin before applying any skin care products. The directions should be followed as on the package.
Presence of Other Ingredients
Certain additives such as fragrances, preservatives, and chelating agents added to cleansing products can increase their irritation potential. Fragrances and preservatives are the most commonly reported causes of contact dermatitis in people. Some preservatives, such as formaldehyde and parabens, are known to cause skin irritation and can lead to allergic reactions.
Furthermore, the use of humectants, emollients, and lipids in cleansing formulations can help counteract the barrier-disrupting effects of surfactants and improve overall skin hydration and nourishment. The addition of skin-identical lipids such as ceramides can help strengthen the skin barrier and reduce TEWL. The use of mild surfactants with low irritancy potential and formulation of products with low pH that are compatible with the skin’s natural pH can also help minimize skin irritation and dryness. Additionally, some skin cleansers incorporate ceramides, which are lipids that are naturally present in the skin barrier. Ceramides help strengthen and protect the skin barrier. Incorporating ceramides into skin cleansers can help repair or prevent damage to the skin barrier. Another ingredient that is often used in mild skin cleansers is glycerin, which is a humectant that helps attract and retain moisture in the skin. Using these and similar ingredients can help create skin cleansers that are gentle while still effectively removing dirt, oil, and other impurities from the skin.
In conclusion, the development of new-generation skin cleansers involves a comprehensive understanding of surfactant solution properties, the skin barrier, and the interplay between surfactants and other formulation components to create products that are effective in removing dirt and oil while minimizing skin irritation and dryness. The formulation of skin cleansers has come a long way over the years, and much progress has been made to develop gentle and mild cleansing systems that minimize damage to the skin barrier. Modification of surfactant solution properties, such as surface charge, micelle size, and shape, as well as the addition of polymers such as polyethylene oxide (PEO) and humectants such as glycerin, are among the various strategies employed to achieve this goal. By optimizing these parameters, it is possible to create surfactant systems that have low irritancy potential and are gentle on the skin. To design a skin-compatible cleanser, it is important to consider the type and concentration of surfactant ingredients, the pH of the formulation, and the rinsability of the product. By minimizing the irritancy potential of the cleansing agent, the integrity of the skin barrier can be maintained and adverse cutaneous responses can be prevented. The design must consider a cleansing formulation that protects the skin barrier. As such, it is important to consider various factors such as the surfactant ingredients, residue or rinsability factor, pH of the cleansing agent, and presence of other ingredients that can increase the irritation potential. A careful balance of these factors is crucial in creating a cleansing formulation that effectively cleanses the skin while also protecting it from damage.
Evolution of Cleansers Into the Cosmeceuticals Space and Cleansing of Compromised Skin
Cosmetics are the main triggering factors of sensitive skin, especially in females, due to overuse and sometimes inappropriate use. The presence of potentially irritating substances in their composition increases the possibility of symptoms. Maintenance of cutaneous pH (5.5 on the surface) keeps the barrier whole and adequately hydrates the skin. When the barrier is compromised, the penetration of substances leads to an inflammatory reaction with the release of a series of cytokines. Thus products that alter cutaneous pH favor sensitive skin. The irritants alter the function of the epidermal barrier so the sensitizing substances, when phagocytized by Langerhans cells, lead keratinocytes and T lymphocytes to produce mediators of inflammation, which impacts sensitive skin.
It’s important to keep in mind that for individuals with sensitive skin, a mild and nonirritating skin cleanser is crucial. The pH of the skin cleanser should be close to the skin’s natural pH, which is ∼5.5. Additionally, the skin cleanser should be gentle and nonstripping, to avoid further compromising the skin barrier. In cases of skin disorders such as AD, acne vulgaris, rosacea, and others, it’s best to consult with a dermatologist for personalized recommendations for skin cleansers that can be used alongside topical therapies and that are compatible with the specific skin condition.
Cleansing in Atopic Dermatitis
For AD, it is recommended to use a gentle, mild, and nonirritating cleanser that can maintain the proper hydration of the skin and help restore its barrier function. The use of synthetic washing bars with a low pH that does not disrupt the skin’s natural moisture levels is recommended for individuals with AD, as they are less likely to cause irritation and further damage to the skin. Additionally, it is advisable to avoid the use of alkaline soaps, as they can strip the skin of its natural oils and increase the risk of skin dryness, irritation, and colonization of gram-positive bacteria. It is best to consult a dermatologist for specific recommendations on skin cleansers for individuals with AD.
Cleansing in Acne
It’s important to note that the ideal cleanser for acne-prone skin should not only be noncomedogenic, nonacnegenic, nonirritating, and nonallergenic but also gentle and effective in removing surface dirt, sweat, and excess skin lipids. Vigorous scrubbing should be avoided, as it can aggravate acne and lead to dryness and irritation. A nonionic, fragrance-free dermatologic bar or liquid cleanser with good rinsability is preferred, and the cleansing regimen should be tailored to the individual patient’s needs. Additionally, highlighted that it’s important to follow a proper skin care routine, such as using noncomedogenic moisturizers, and to seek the advice of a dermatologist to determine the best course of treatment for the individual’s specific acne condition.
Cleansing in Rosacea
In patients with rosacea, it is important to use gentle, nonirritating skin cleansers to prevent further irritation of the skin and exacerbation of symptoms. Sulfacetamide sulfur–based therapeutic skin cleansers are specifically designed for the treatment of rosacea and have been approved for use. However, individuals with known hypersensitivity to sulfonamides, sulfur, or other components should avoid using these cleansers. It is also recommended to avoid classic soaps, cleansers with alcohol, astringents, and abrasives and to perform gentle cleansing in rosacea patients. Further details of caring for such skin are described by and .
Cleansing in Photoaged Skin
It is important to choose skin-cleansing agents carefully in individuals with photoaged skin. Cleansers containing ingredients such as glycolic acid, retinol, and AHAs should be avoided, as they can cause further irritation and dryness to the already damaged skin. Mild, nonirritating, and fragrance-free cleansers are recommended for individuals with photoaged skin, as they help in maintaining proper hydration and nourishment of the skin. In addition to cleansing, individuals with photoaged skin should also follow a comprehensive skin care regimen that includes the use of sun protection products, moisturizers, and antiaging treatments to prevent further damage to the skin. described the condition of such a skin type and the impact of different types of products on it.
Cleansing in Occupational Dermatosis
It is important for individuals with occupational dermatosis to practice good skin care and use skin-cleansing products that are compatible with their skin. The ideal skin cleanser for occupational dermatosis should be easy to dissolve in both hard and soft water, be able to remove oils and greasy materials without drying the skin, and have a long shelf life without easy deterioration. and have described the problem of such skin disorders and the how to address it. However, it is difficult to label a single cleanser as ideal for all cases of occupational dermatosis. A skin-friendly cleanser without scrubbing agents is often recommended by dermatologists.
Cleansing in Xerotic Skin
Xerotic skin is a common occurrence in various skin conditions and in older individuals as a result of the natural aging process, which leads to a decrease in sebum production. Low humidity and windy conditions can worsen the dryness. To combat xerotic skin, emollients, humectants, or agents that soften keratin should be used liberally and reapplied frequently after bathing. It’s recommended to read the review by for further understanding of this skin disorder. People with xerosis should choose cleansing products that are gentle and contain humectants or emollients to avoid further drying the skin.
Cleansing in Sensitive Skin
Sensitive skin is defined by dermatologists and cosmetic scientists as skin that reacts more easily to irritants and allergens than the average population. This heightened reactivity can be due to physiologic factors, increased neurosensory input, heightened immune responsiveness, or a compromised skin barrier. To care for sensitive skin, it is recommended to use very gentle cleansing agents, such as liquid facial cleansers. These products are highly effective and beneficial for sensitive skin and can be used in conjunction with other topical or systemic treatments. have described the problems and treatment of this skin type in detail.
Cleansing in Retinoid-Induced Dermatitis and Post–Chemical Peel
Topical retinoids, commonly used for various skin conditions, can make the skin more prone to irritation. In such cases, patients should use a cleanser that does not further weaken their skin barrier. Cleansers containing humectants and emollients, such as lipid-free cleansers, may help alleviate symptoms. Facial chemical peels, which have gained popularity as cosmetic treatments for photoaging, wrinkles, scars, and discoloration, involve controlled injury to the skin to promote growth of new, improved skin. During the healing process, the skin is vulnerable, so mild cleansing agents should be used to avoid any adverse reactions. described the impact of mild cleansing and its management for such a skin disorder.
Cleansing in Idiopathic Perianal Pruritus
Perianal pruritus is an itchy sensation in the skin around the anus that leads to scratching. It can be primary, with no known cause, or secondary, caused by a specific factor. Topical corticosteroids are effective for treating primary perianal pruritus, but extended use can result in skin atrophy in the anal and genital areas. Mild liquid cleansers containing humectants, used for perianal cleansing, can be a safe first step in controlling itching and can be just as effective as topical corticosteroids.
Moreover, in individuals with sensitive skin, there is a decrease in ceramide levels and in skin hydration (capacitance). Skin conditions that impair the skin barrier, such as AD, seborrheic dermatitis, and rosacea, are predisposing factors for sensitive skin. These dermatitis conditions, as well as acne, rosacea, seborrheic dermatitis, contact dermatitis, psoriasis, and physical urticaria (dermographism), involve alterations in the skin barrier or inflammation. In these patients, sensitive skin can be considered an objective form, characterized by visible skin lesions, erythema, dry skin (xerosis), and eczema. When there is erythema, the diagnosis of sensitive skin may be mistaken for various dermatitis conditions. However, the presence of unusual sensations, triggering factors, and a transient nature suggest the diagnosis of sensitive skin. In recent years, there has been significant progress in the formulation of facial cleansers, leading to the creation of new, gentler products that are more suitable for different skin types. The latest developments in galenic science have resulted in the creation of formulas with milder surfactants. Surfactants are the key ingredients in most cleanser formulas and play a crucial role in cleansing. They help mix oils and dirt with water, but the type and amount of surfactants used can affect the drying and irritating potential of cleansers.
Facial cleansers have evolved in recent years to become gentler on the skin and better suited for specific skin conditions. Newer formulas contain milder surfactants and are designed to preserve the integrity of the skin barrier and maintain its natural moisture levels. To target specific dermatologic disorders, such as acne, rosacea, photoaging, and hyperpigmentation, new ingredients have been added to the formulas. This allows these new-generation cleansers to enhance the results of therapeutic treatments. The treatment of dark spots offers a variety of options formulated to target different types of hyperpigmentation, skin phototypes, and body parts. These cleansers not only cleanse and purify the skin but also reduce glycation and oxidative processes, helping control the biochemical reactions that may stimulate melanin production. They also reinforce cell-to-cell communication, preparing the skin for better absorption of active ingredients in subsequent treatments. described the cleansing process of this skin type and its treatment.
Future of Skin Cleansing
Facial cleansers have evolved over time to become gentler on the skin and provide added benefits. Increasing environmental concerns, advancements in biotechnology, and the emergence of increasingly stringent laws have led to biosurfactants becoming a credible alternative to the synthetic surfactants available on the market. Harsh surfactants can cause damage to skin proteins and lipids, leading to skin dryness. Newer, milder surfactants and pH-balanced formulations have been developed to minimize skin damage. The addition of mildness enhancers and moisturizing agents, such as lipids, occlusives, and humectants, can minimize surfactant damage to skin proteins and lipids and replenish skin lipids lost during cleansing. The goal of these ingredients is to improve the overall health of the skin barrier and prevent dryness and irritation.
Sustainable Sourcing of Surfactants and Their Environmental Impact
The vigorous current movement for industrial sustainability has stimulated active interest in biosurfactants as possible replacements for at least some of these chemical surfactants. In addition to biosurfactants being produced from renewable feedstocks, they also have characteristics that fall under the term environmentally friendly . The fact that they can be readily biodegraded means that they are significantly less damaging to the environment than the more recalcitrant chemical surfactants, and their ability to withstand high temperatures and tolerate high salt concentrations makes them attractive components for many industrial products.
Biosurfactants are surface-active agents of biologic origin, mainly produced by bacteria, yeast, or filamentous fungi as secondary metabolites. Biosurfactants are obtained from these microorganisms through separation processes such as extraction, precipitation, and distillation without adding any organic synthesis before, during, or after production, and as such, biosurfactants are also termed naturally derived surfactants . Biosurfactants are generally neutral or anionic in nature. However, those that contain amine groups are cationic in nature. The diverse functional properties of biosurfactants, which include emulsification, wetting, foaming, cleansing, phase separation, surface activity, and reduction in viscosity of heavy liquids such as crude oil, make them appropriate for many industrial and domestic applications.
Advantage of Biosurfactants Over Synthetic Surfactants
When compared to conventional surfactants found in soaps and syndets, the main advantages of these novel surfactants include their high biodegradability profile, creating less hazardous waste. These new surfactants are also known for their renewability, low toxicity, and stability under various conditions (such as extreme temperature and pH), making them suitable for use across different industries. Unlike synthetic surfactants, the components of biosurfactants such as sugars, lipids, and proteins are similar to those found in the membrane of skin cells (phospholipids and proteins). Moreover, the movement of compounds across the membrane of skin cells is dependent on their lipophilicity and surface activity. and have furthermore shown that the unique structure of biosurfactants offers them a high rate of permeability through the membrane of skin cells to regulate protein and skin barrier functions; they also trigger beneficial effects relating to hair repair and skin protection mechanisms. Such properties allow these surfactants to be used across various industries (e.g., cosmetic, food, laundry, pharmaceutical) in a range of processes to reduce surface tension and to promote the penetration of bioactives through biologic membranes as demonstrated by and .
Origin of Biosurfactants
Nowadays, a rise in product demand and environmental awareness is driving the development of a new generation of sustainable and environmentally friendly ingredients, including biosurfactants of plant origin, microbial origin, and amino acid–based surfactants.
Biosurfactants of Plant Origin
Plant-based surfactants are naturally omnipresent in different parts of plants, including the roots, stems, leaves, flowers, fruit, and seeds. Like any other conventional surfactants, they are amphiphatic molecules that constitute a diverse group of compounds characterized by a structure made up of phospholipids such as lecithin, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, proteins or protein hydrolysate, and saponins. For details about the production of such biosurfactants, please refer to the article by . Recently, have reported that lecithin can be useful as a skin-friendly surfactant for application in skin care products. Its impact on skin barrier function was found to be considerably lower than that of conventional anionic surfactants such as SLS. Thus its use on sensitive skin with preexisting conditions such as eczema can be considered and should be explored further.
Biosurfactants of Microbial Origin
Biosurfactants of microbial origin are a structurally diverse group of compounds that includes phospholipids, fatty acids, glycolipids, lipopeptides such as surfactin, and lipopolysaccharides. The hydrophilic portion of a microbial biosurfactant can be composed of a carbohydrate, amino acid, cyclic peptide, phosphate, carboxylic acid, or alcohol, while the hydrophobic portion can be composed of long chain fatty acids or hydroxylated fatty acids. A variety of microorganisms, including bacteria (e.g., Bacillus subtilis , Pseudomonas aeruginosa ), yeasts (e.g., Candida lipolytica , Candida bombicola ), and filamentous fungi (e.g., Phoma herbarum ), can effectively produce biosurfactants with different molecular structures and surface activities. For further details on this, please refer to the articles by , , and .
Amino Acid–Based Surfactants
Amino acid–based surfactants are synthetic equivalents to biosurfactants. As novel surfactants, they can be synthesized via different biotechnological and chemical routes using renewable sources, mainly amino acids. Their high degradability and harmless by-products make them safer for the environment. There are a total of 20 standard amino acids that are responsible for cell growth and all physiologic reactions in living organisms. Some amino acids are hydrophobic, others are hydrophilic, some are basic, and some are acidic, making it possible to produce an extensive range of surfactants with great potential as biocompatible, sustainable, and eco-friendly substances. Some examples include nonionic phenylalanine- and leucine-derived surfactants; cationic cocoyl arginine ethyl ester; anionic sodium N-cocoyl-L-glutamate and potassium N-cocoyl glycinate; amphoteric lauroyl lysine; and alkoxy (2-hydroxypropyl) arginine. Their simple and natural structures, low toxicity, mildness, and rapid biodegradation often make them superior to their traditional counterparts. For example, sodium or potassium N-cocoyl glycinate was found to be mild to skin when applied and used in face cleansers. Similarly, N-dodecanoylalaninate is known to produce a nonirritating creamy foam, making it particularly suitable for products intended for the likes of baby skin.
Overall, the development of new and sustainable surfactants, such as biosurfactants and amino acid–based surfactants, has opened new opportunities for the development of environmentally friendly and skin-friendly cleansers. Although the use of biosurfactants in skin cleansers is still in its early stages, the potential for their development as a new generation of cleansers is significant. These surfactants are mild and can reduce skin damage, dryness, and irritation, which can be common side effects of harsh surfactants. Additionally, lecithin can help hydrate the skin and maintain its natural moisture level. Through several in vitro studies, and have demonstrated that rhamnolipids, sophorolipids, mannosylerythritol lipids (MELs), and surfactins are compatible with the human skin. In summary, the use of biosurfactants in skin care products offers a mild, sustainable, and skin-friendly alternative to traditional surfactants while still providing the necessary cleansing and foaming properties and is the future of skin cleansing.
Conclusion
The course of development of skin cleansers has been one of continual improvement. Soap-based products, used since antiquity, offered improved cleansing over mechanical methods or water alone but could irritate and dry the skin. Bars based on synthetic detergents that offer improved skin compatibility compared with soap have become available over the past several decades. Body washes have been growing in consumer popularity. Progress in liquid cleanser technology will continue in the coming years. The success of the technology will depend on how effectively the deposition and delivery of benefit agents can be balanced against the ability of the cleanser to provide freshness and cleanliness with the desired in-use sensory and lather properties. Cleansers have evolved significantly from just serving as cleaning agents for removal of sebum, dirt, dead cells, and microorganisms from skin, mainly because of the challenge of meeting ever-changing consumer expectations. With the advent of advanced technologies, newer cleansers are now being manufactured that are mild, provide moisturizing benefits, and can be easily washed off. In various dermatologic disorders, all the properties of modern cleansers enable them to be used concomitantly with topical therapeutic measures, thus influencing the outcome of treatment and progression of the disorder. Dermatologists can enhance the overall management of various skin disorders by advising their patients in how to adjust their cleansing regimen to best suit their needs and achieve optimal results with therapy.
Further Reading
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