Medicosnext
Shampoo is a basic hair care product representing the largest segment of hair care cosmetics. Shampoo treatments are the most commonly used means of managing hair and scalp conditions. In order to maintain the physiological balance of hair essential elements, to leave hair glossy for beautifying them and improving their aesthetical appeal, the cleaning process should be mild. A shampoo should also be easy to remove through rinsing with water, it should produce a good amount of foam to satisfy the expectations of the users, and it should be non-toxic and non-irritating for hair and scalp, avoiding any side effects or skin and eye irritation.
What does a shampoo contain?
It is important to realize that the only ingredients that are important for cleansing and manageability of the hairs are the synthetic detergents and the conditioners, while the rest aid in the stability, presentability, and marketability of the product. A brief discussion of the ingredients is as follows.
Shampoo surfactants:
The cleansing ability of a shampoo depends on the surface activity of its detergents. Surface-active ingredients, or surfactants, facilitate the removal of environmental dirt by reducing surface tension between water and dirt; dirt is suspended in the water phase and adsorption prevented. Surfactants are classified according to hydrophilic polar group as anionic, cationic, amphoteric, and nonionic.
a. Anionic surfactants: Anionic surfactants are characterized by a negatively-charged hydrophilic polar group. Among them, ammonium lauryl sulfate, sodium laureth sulfate, sodium lauroylsarcosinate, SDS, alpha-olefin sulfonate, and ammonium laureth sulfate can be cited. Anionic surfactants are very good in removing sebum and dirt; however, they are strong cleaners and may induce an increase of electrical negative charges on the hair surface, creating frizz and friction. Therefore, in order to reduce damages and to have a mild detergency, secondary surfactants such as nonionic and amphoteric surfactants are usually added in the formulation.
b. Cationic surfactants: Cationic surfactants have a positively charged hydrophilic end and are used mainly as conditioners, being able to balance hair negative charges after washing, reducing frizz. Indeed, they are efficient softeners and substantive for hair, because of the hair’s low isoelectric point (pH 2.15–3.17). Typical examples are trimethylalkyl ammonium chlorides, benzalkonium chloride or bromide, and so on.
c. Amphoteric surfactants: Amphoteric surfactants contain both negatively and positively charged hydrophilic polar groups. At low pH values, they behave as cationic agents, and at higher pH values, as anionic agents, and are thus classified between cationic and anionic surfactants. Examples include betaine, sulfonate betaine, amphoteric acetate/diacetate. They are considered very mild, and thus dermatologically compatible. They are used in baby shampoo and for those with fine and damaged hair because they don’t cause stinging in the eyes in children, foam well, and leave hair in manageable state.
d. Nonionic surfactants: Nonionic surfactants differ from other surfactants in that they do not possess a charged polar group and are hence compatible with all other surfactants. They are also among the mildest form of surfactants; they make good cleansers with dispersion and emulsification properties, but lather poorly. In combination with alkyl ether sulfates or amphoteric surfactants, they serve to enhance tolerability in very mild cleansers, such as baby shampoos. Examples of nonionic surfactants are fatty alcohol ethoxylates, sorbitan ether esters, and alkyl polyglucosides.
Conditioners:
Hair-conditioning ingredient functions to impart manageability, gloss, and antistatic properties to the hair. This may be included in the shampoo, which then serves dual function of cleaning and conditioning. These are useful for those wishing to shampoo daily, and for dry, damaged, or chemically treated hair. Commonly used conditioning substances include hydrolyzed silk and animal protein, glycerin, dimethicone, simethicone, polyvinyl pyrrolidone, propylene glycol, and stearal -konium chloride.
Foaming agents:
They introduce gas bubbles into the water, but have nothing to do with cleansing. A common myth among the general public is that a product which foams better cleans better. Inclusion of foam boosters like cocodiethanolamide as ingredients in shampoo helps to satisfy the customer psyche, which equates good foaming with good cleansing though it does help spread the detergent over the hair and scalp. This helps in the commercial success of a shampoo formulation. Sebum inhibits the bubble formulation; therefore, there is more foam during second shampooing.
Thickeners and opacifiers:
These are added to change the physical and optical properties of the shampoo. This improves the cosmetic acceptance. Many shampoos are pearlescent. This effect is achieved by addition of tiny flakes of suitable materials, for example, glycol distearate. Thickeners like salt (sodium chloride) and PEG-150 distearate are used to increase the product viscosity.
Preservatives:
Preservatives resist germs and prevent decomposition of the shampoos. They also prevent various other health risks that accompany contamination by germs and bacteria. Typical preservatives in shampoos are sodium benzoate, parabens, 1, 3-dimethylol-5, 5-dimethyl (DMDM) hydantoin, tetrasodium EDTA, methylisothiazolinone, or MIT, and quaternium-15.
Additives
Recently, an attractive list of ingredients is being added to shampoos, ranging from chemical sun screens to vitamins like panthenol, pro-vitamins, and botanicals like tea tree oil, and even beer. The contact time of shampoos with scalp and hair is too brief to expect significant clinical benefits, despite claims to the contrary. These additives serve mainly to allow the distinction of one shampoo from another in terms of marketing claims.
Who should use which shampoo?
A common question of a dermatology patient, especially if he or she comes with a hair problem, is to ask the type of shampoo he or she should use for their type of hair. Dermatologists are expected to be familiar with the basic types of shampoos available in the market.
• Normal hair shampoo is for people who have hair that are chemically untouched, and scalp that produces moderate sebum. Favorite with men. Normal hair shampoos use lauryl sulfate as the primary detergent, providing good cleansing and minimal conditioning.
• Dry hair shampoo is for people who have undergone chemical treatment or harsh styling procedures. These shampoos provide mild cleansing and good conditioning.
• Oily hair shampoo is for people who produce abundant sebum. They contain lauryl sulfates or sulfosuccinates as detergents and no conditioners.
• Everyday shampoo is for people who want to wash their hair daily along with bath. They generally contain mild detergents and typically do not incorporate the conditioners. But, an instant stand-alone conditioner is recommended, which can be applied immediately after shampooing in the shower and completely rinsed from the hair prior to drying.
• Deep cleansing shampoo is for people who frequently use styling products, such as hair spray, gel, and mousse. These polymers build up on the hair shaft after continuous use and make the hair look rough and dull and feel harsh. To remove these polymers, a strong detergent like lauryl sulfates is used as their primary detergent. These shampoos are typically used once weekly.
• Baby shampoo is for babies where mild detergent is used, which is non-irritating to the eyes and achieves mild cleansing, as babies produce limited sebum. They contain the amphoteric group detergents, such as the betaines, which actually numbs the eye tissues to prevent stinging and irritation. So, it can still potentially damage the eye if accidentally introduced, and care should be taken while bathing the child.
• Medicated shampoo is used for people with scalp problems like seborrheic dermatitis, psoriasis, and bacterial or fungal infections. In addition to regular cleansers, they contain active agents like tar derivatives, corticosteroids, salicylic acid, sulfur, selenium sulfide, polyvinylpyrrolidone-iodine complex, chlorinated phenols, or zinc pyrithione. Two-in-one (popularly known as “2-in-1”) shampoos, which contain silicone in the form of dimethicone as conditioner, and mild detergents, such as the laureth sulfates, or cationic detergents, which produce reasonably good foam. Thus, after shampooing, the sebum is replaced with silicone to make the hair shiny, soft, and free of static electricity.
• Professional shampoos are not for ordinary people, but for use of professional hair stylist and cosmetologist. They are either used before a cutting or styling procedure, or before and after a chemical process like bleaching and dyeing or coloring process. Briefly, these shampoos have ingredients in extremely concentrated forms, or special anionic or cationic detergents that neutralize the harsh effects of chemicals on hair shaft or remove the residues of chemicals applied to achieve a particular hair style or color. They are not to be used for day-to-day hair care.
Tips for healthy hair
How you wash your hair, and the products you use, can go a long way towards maintaining smooth, shiny hair. Follow these simple tips from dermatologists to maintain healthy hair.
1. Wash oily hair more frequently. How often you wash your hair should be based on how much oil your scalp produces.
o If your scalp is oily, you may need to wash it as often as once a day.
o If you have chemically treated hair, your hair may be drier, so you may want to wash it less frequently.
o As you get older, your scalp makes less oil, so you may not need to shampoo as often. But, if you see flakes in your hair, you may not be shampooing enough. This can lead to dandruff and other scalp diseases.
2. Concentrate shampoo on the scalp. When washing your hair, concentrate on cleaning primarily the scalp, rather than washing the entire length of hair. Washing only your hair can create flyaway hair that is dull and coarse.
3. Use conditioner after every shampoo unless you use a “2-in-1” shampoo, which cleans and conditions hair. Using a conditioner can significantly improve the look of damaged or weathered hair by increasing shine, decreasing static electricity, improving strength, and offering some protection from harmful UV rays.
4. Concentrate conditioner on the tips of the hair. Because conditioners can make fine hair look limp, they only should be used on the tips of the hair and not on the scalp or length of the hair.
5. Choose a shampoo and conditioner formulated specifically for your hair type. For example, if you color your hair, use a shampoo designed for color-treated hair. If your hair is damaged or chemically treated, consider a “2-in-1” shampoo. Regardless of cost, many shampoo and conditioner brands provide the same benefits.
6. Protect hair when swimming. Protect your hair from the damaging effects of chlorine by wetting and conditioning your hair before swimming. Wear a tight-fitting swim cap and use a specially formulated swimmers shampoo and deep conditioner after swimming to replace lost moisture.
