What is a scalp exfoliator composed of?

Hair scrub products provide a gentle exfoliation to the scalp, the principle of which is to lift off flaking corneocytes and remove other impurities that accumulate between two shampoos by rubbing micro-grains on the skin (dust, pollution residues, traces of hair products used, etc...). However, if they remain on the surface of the scalp, they tend to clog the pores and impair the overall health of the scalp (dandruff, itching, excess sebum) and hair (lack of volume, slowed growth). The exfoliating agents also activate the blood flow to your scalp during the massage. This will help to soften it but also improve the growth of your hair. Conditioned on an emulsified or gelled base, these active ingredients are either of plant origin (like jojoba micro-beads, crushed apricot kernels...), or of mineral origin (like silica powder).

Historically, polyethylene microbeads have been a common ingredient in such products, favoured for their gentleness on the skin, low cost, and ease of manufacture. Banned since 1st January 2018 in cosmetics, they are accused of harming the ecosystem (made from petroleum, resistant to biodegradability, accumulation in marine waters).

Some scalp scrubs provide a dual exfoliation, both mechanical and chemical, meaning that their composition includes, in addition to acidic agents such as AHA like the glycolic acid, BHA like the salicylic acid or PHA like the gluconolactone. They act on the bonds between dead cells for optimal exfoliation. The micro-grains, more or less abrasive depending on the size and shape of the granules, are generally combined with soothing and moisturising agents like the aloe vera, propanediol, etc... in varying quantities.

Other substances are also essential to the composition of a hair exfoliant such as the gelling agents (example: sclerotium gum, xanthan gum, etc...) which have the property of giving the product consistency by increasing its viscosity, pH regulators (example: citric acid, sodium hydroxide, etc...) to stabilise the preparation and adjust the pH of the hair scrub to that of the scalp, emulsifiers (example: polyglyceryl-4 caprate, etc...) used to slow down instability between two immiscible liquids by reducing the surface tension between these two liquid phases, fragrance/flavouring agents (example: essential oils, limonene, linalool, lyral etc...) which allow to give a scent to the product by creating a pleasant smell and/or masking a bad smell, and one or more agents with bacteriostatic activity (example: sodium dehydroacetate, potassium sorbate, etc...) which serve to inhibit the proliferation of bacteria by altering the cellular membrane of microorganisms and thus preserving the microbiological cleanliness of the product at the time of their use. Indeed, exfoliating creams or gels are mainly composed of water, a medium conducive to the development of bacteria.