Cleansing, conditioning and beautifying the skin and hair are important aspects of maintaining the outward health and appearance of the body. An understanding of the mechanism of action and chemistry of products designed to improve the ability of the skin and hair to function is medically important.
Cleansing of the skin is a complex interaction between the stratum corneum barrier, environmental dirt, body secretions, and a surfactant. Washing of the skin is necessary in terms of personal hygiene and health.
Hair cleansing and conditioning are more complex interactions than skin cleansing because the surface to cleanse is greater, consisting of the scalp and all surfaces of each hair shaft. Products designed to cleanse the hair are known as shampoos. Products designed to beautify the cleansed hair are known as conditioners.
SKIN CLEANSING PRODUCTS:SOAP: Most cleansing is accomplished with soap, which is obtained through the chemical reaction between a fat and an alkali, resulting in a fatty acid salt with detergent properties. Modern refinements include adjustment of the alkaline pH to reduce skin irritation and to incorporate substances that prevent precipitation of calcium fatty acid salts in hard water, known as soap scum.
Bar and liquid cleansers can be divided into 3 basic types, as follows[7, 8] :
- True soaps composed of long chain fatty acid alkali salts with a pH of 9-10
- Combars composed of alkaline soaps to which surface active agents have been added, also with a pH of 9-10
- Synthetic detergent bars composed of synthetic detergents and fillers that contain less than 10% soap and that have an adjusted pH of 5.5-7
Common ingredients in bar-type cleansers are sodium cocoate, sodium tallowate, sodium palm kernelate, sodium stearate, sodium palmitate, triethanolamine stearate, sodium cocoyl isethionate, sodium isethionate, sodium dodecyl benzene sulfonate, and sodium cocoglyceryl ether sulfonate. Detergents in liquid formulations are sodium laureth sulfate, cocoamido propyl betaine, lauric acid diethenolamine (lauramide DEA), sodium cocoyl isethionate, and disodium laureth sulfosuccinate.
Special additives to the basic soap types are responsible for the tremendous variety of soaps marketed today. Lanolin and paraffin may be added to a moisturizing synthetic detergent soap to create a superfatted soap, whereas sucrose and glycerin may be added to create a transparent bar. Adding olive oil instead of another form of fat distinguishes a castile soap.
Medicated soaps may contain benzoyl peroxide, sulfur, or resorcinol antibacterials (eg, triclocarban or triclosan). Triclocarban is excellent for eradicating gram-positive organisms, but triclosan eliminates both gram-positive and gram-negative bacteria. These soaps have a pH of 9-10 and may cause skin irritation.
Additives are also responsible for soap’s characteristic appearance, feel, and smell. For example, titanium dioxide is added in concentrations as high as 0.3% to opacify the bar and increase its optical whiteness. Pigments (eg, aluminum lakes), can color the bar without producing colored foam, which is considered an undesirable characteristic.
Foam builders (eg, sodium carboxymethylcellulose and other cellulose derivatives) can make the lather feel creamy. Perfume in concentrations of 2% or more also can be added to ensure that the soap bar smells pleasant until it is completely used up.
Body washes are a special subset of liquid synthetic detergents that combine mild skin cleansing with moisturizing and emollient qualities. They are applied with a puff that does not support bacterial growth to break the emulsion through the incorporation of generous amounts of air and water. High amounts of petrolatum can be incorporated in body wash emulsions to improve skin dryness and hydration.
Different types of facial cleansers have been developed for people with different skin types. Active cleansers are more suitable for oily skins to prevent breakouts. But they may overdry and irritate dry skin, this may make the skin appear and feel worse. Very dry skin may require a creamy lotion-type cleanser. These are normally too gentle to be effective on oily or even normal skin, but dry skin requires much less cleansing power. It may be a good idea to select a cleanser that is alcohol-free for use on dry, sensitive, or dehydrated skin.
Abrasive scrubs incorporate polyethylene beads, aluminum oxide, ground fruit pits, or sodium tetraborate decahydrate granules to induce various degrees of exfoliation. The main problem with abrasive scrub products for epidermabrasion is related to the firm scrubbing granules, which do not deform when pressed hard against the skin. LUFA, WOVEN MESH SPONGES.
HAIR CLEANSING PRODUCTS:
Shampoos basically contain detergents, foaming agents, thickeners and opacifiers, conditioners, sequestering agents, pH adjusters, specialty additives, and other ingredients (eg, softeners, fragrances, preservatives)
Shampoos function by using detergents (also known as surfactants) that are both lipophilic (oil loving) and hydrophilic (water loving). The lipophilic component adheres to sebum, and the hydrophilic component allows water to rinse away the sebum.
Some of the most common synthetic detergents combined into shampoo formulations for various needs are as follows:
- Lauryl sulfates (sodium lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate)
- Laureth sulfates (sodium laureth sulfate, triethanolamine laureth sulfate, ammonium laureth sulfate)
- Sarcosines (lauryl sarcosine, sodium lauryl sarcosinate)
- Sulfosuccinates (disodium oleamine sulfosuccinate, sodium dioctyl sulfosuccinate)
TYPES OF SHAMPOO:Shampoos are formulated in liquids, gels, creams, aerosols, and powders
Basic shampoos may be selected from several formulations, depending on the amount of sebum production in the scalp and depending on the diameter and condition of the hair shaft. The label usually defines the intended purpose by stating “normal hair,” “oily hair,” “dry hair,” “damaged hair,” or “color-treated hair.”
Normal-hair shampoos use lauryl sulfate detergents, which have good cleansing and minimal conditioning characteristics. These products work well for adults with moderate sebum production and coarse hair; however, they do not work well for persons with fine, unmanageable hair.
Oily-hair shampoos have excellent cleansing and minimal conditioning properties. They may use lauryl sulfate or sulfosuccinate detergents and are intended for adolescents with oily hair or persons who have extremely dirty hair. They can be drying to the hair shaft if used daily. Using a heavy conditioner after an oily-hair shampoo is self-defeating.
Dry-hair shampoos provide mild cleansing and good conditioning. Some companies recommend the same product for dry hair and damaged hair. These products are excellent for mature persons and for those who wish to shampoo daily. They reduce static electricity and increase manageability in fine hair; however, some products provide too much conditioning, which may result in limp hair.
Damaged-hair shampoos are intended for hair that has been chemically treated with permanent color, bleaching agents, permanent waving solutions, or straighteners. Hair can also be physically damaged by overcleansing, by excessive use of heated styling devices, and by vigorous brushing or combing. Long hair is more likely to be damaged than short hair because it undergoes a natural process known as weathering, whereby the scales of the cuticles are decreased in number from the proximal end to the distal end of the hair shaft.
Baby shampoos are designed to be nonirritating to the eyes and to provide only mild cleansing because babies produce limited sebum. These shampoos contain detergents from the amphoteric group. Baby shampoos are also appropriate for use on mature hair and for individuals who wish to shampoo daily.
Conditioning shampoos may be labeled as such, or they may be labeled as shampoos for dry or damaged hair. Detergents used in conditioning shampoos generally are amphoterics and anionics of the sulfosuccinate type. These products sometimes are known as 1-step shampoos, because a conditioner need not be applied afterward.
Medicated shampoos, also known as dandruff shampoos, contain additives, such as tar derivatives, salicylic acid, sulfur, selenium disulfide, polyvinylpyrrolidone-iodine complex, chlorinated phenols, or zinc pyrithione. Medicated shampoos have several functions: to remove sebum efficiently, to remove scalp scale, to decrease scalp scale production, and to act as an antibacterial or antifungal. The shampoo base removes sebum, and mechanical scrubbing removes scalp scabs.
Tar derivatives commonly are used as anti-inflammatory agents. Sulfur and zinc pyrithione are used for their antibacterial or antifungal qualities. Menthol is added to some shampoos to produce a tingling sensation that some patients find esthetically pleasing.
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