Shampoo ingredients and their functions

read the labelWhen using shampoo we are mostly looking for cleaning our hair. This should be the main function of any shampoo. Because the hair follicle releases oily substances that coat the “root” of the hair, dust and dirt often get attracted to this greasy coating, and can serve as a fertile substance for germs and other diseases. In addition to cleaning, shampoo manufacturers also add shampoo ingredients that perform secondary functions. Some of these functions are important for keeping the hair and the scalp in good condition, and others are important for the consistency of the shampoo itself. Main functions of shampoo ingredients include –

Cleaning ingredients – these are called detergents, or surfactants. Sulfate-based detergents are the most common ones in shampoos because they are cheap and effective. They are, however, irritant, so sensitive people try to avoid them, and find alternatives.

Skin conditioners – also called emollients, are the substances that soothe the scalp skin, and protect the hair. These conditioners are often oils that are added to the shampoo such as rosemary, aragan, or tea tree oils, but can also be synthetic chemicals such as paraffin or mineral oil.

Moisturizers – humectants are substances that tend to pull water molecules from their environment and maintain the moisture around them. When used in shampoo, they will retain or add moisture to the hair and scalp, prevent hair breakage and scalp problems. One of the most common synthetic humectant is glycerin, but a good example of a natural one would be aloe vera gel.

Hair conditioners – will cover the hair with a thin film that will prevent water loss and splitting. Conditioners also help with frizz control, detangling and styling, making your hair smooth and shiny. One of the major groups of conditioners is the organic silicones. These include many synthetic materials that their name ends with –cone, such as Dimethicone or Amodimethicone. Depending on the silicone used, some may stick to the hair and build up, causing attraction of more dirt, instead of cleaning. This is a concern for some users, more than a safety concern. Among the natural hair conditioners aragan oil is an example.

Preservatives and emulsifiers are shampoo ingredients that have no purpose in hair treatment, but are used to make a uniform mixture of all shampoo ingredients (emulsifiers), and prevent the shampoo product from soiling (preservatives). Here too, you’d be able to find synthetic and unsafe ingredients such as paraben, in some shampoos, and some safer alternatives in shampoos from more health-conscious brands.

Fragrance ingredients affect the scent of the shampoo. If you don’t like the scent of the shampoo, it is likely you’d avoid it, no matter how good the shampoo is in cleaning and maintaining the health of your hair. Because the amounts of fragrance ingredients required to affect the scent of the shampoo is so minute, shampoo brands often do not report what ingredients the  are using. Some fragrance ingredients, such as, Benzyl Salicylate, Coumarin or Limonene are irritants and allergens.

As you can see from the examples given above, many of the functions can be achieved by synthetic ingredients, as well as natural ingredients. Although most of the shampoo ingredients are generally safe, there are many examples of shampoo ingredients that may cause irritation, allergic reaction or even more severe effects such as cancer. When a shampoo contains ingredients with safety concern, it is probably better to look for a shampoo that contains alternative, safer ingredients that perform the same functions.

A comprehensive resource of safe and natural shampoo ingredients is found here.

7 thoughts on “Shampoo ingredients and their functions

    1. Tuft Post author

      Unfortunately, each shampoo brand adds different additives. In my opinion, it is important to look at the substitutes for sulfate-based detergents. Not all of them are better than SLS and SLES, and their siblings. For example, Cocoamidopropyl Betain is one of the common ones, that is better to avoid, if possible. The more expensive ones, such as plant based glucosides are milder, and significantly safer. I hope that helps.

      1. Talavane Krishna

        Thank you kindly for the information on Sulfate free shampoo. Could you give me the names of a few plant based glucosides as detergents, which are milder and cause good foaming?
        Kind regards

        1. Tuft Post author

          An extensive article is well overdue, but here is a “short” answer.
          Natural ingredients include plants such as Soapberry (Sapindus mukorossi)
          Soapwort (Saponaria officinalis)
          Yucca Root
          sarsaparilla (Smilax aspera)
          soap bark (Quillaja saponaria)
          ivy agave
          These are rarely included in commercial shampoos, though. They are expensive.

          Safe non-ionic detergents, such as fatty alcohol ethoxylates, sorbitan ether esters, and alkyl polyglucosides, do not lather as well, and will often be found in combination with other surfactants and foam boosters. Specific examples are Sorbitan Olivate, Lauryl Glucoside, Coco glucoside and Sodium Hydroxypropylsulfonate Laurylglucoside Crosspolymer, to name a few.
          Amphoteric detergents are compounds that can be used as an acid and as a base. These include betaines, sultaines, and imidazolinium derivatives. In this group, try to avoid Cocamidopropyl betaine that has been associated with irritation and allergic contact dermatitis, but there are numerous safe ingredients such as Lauryl betaine, capryl/ capramidopropyl betaine, coco/sunfloweramidopropyl betaine Cocamidopropyl hydroxysultaine, Lauryl sultaine, Butylether hydroxypropyl sultaine and Lauryl hydroxysultaine and many others.
          Lastly, SLS and SLES are anionic detergents. In this family there are safe alternatives too, an example is Sodium Methyl Cocoyl Taurate. Avoid Sodium olefin sulfonate which may cause irritation to eyes and skin.

          I hope that helps.


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