Why is salicylic acid used in numerous cosmetics?

Salicylic acid, or 2-hydroxybenzoic acid, is a molecule extracted from willow bark, but it can also be found in many fruits and vegetables (tomatoes, melons, cucumbers, almonds, spinach...).

Discovered in 1829 by the pharmacist Pierre-Joseph LEROUX, this active ingredient is commonly used in medicine, for treating fever and pain. Indeed, aspirin is an ester synthesised from salicylic acid.

Beyond the medical field, salicylic acid is also a favoured ingredient in the production of skincare products, particularly to diminish blemishes of all kinds, and to care for combination to oily skin types.

Salicylic acid is used in numerous skincare products due to its multiple properties:

• Keratolytic action : Salicylic acid removes the layer of keratin present on the skin's surface (horny layer) and thus stimulates cellular renewal. Indeed, thanks to this keratolytic action, salicylic acid is used in treatments against warts, acne or even psoriasis depending on the dosage. Moreover, to combat dandruff, it can also be used on the scalp. It is also suitable for skin prone to ingrown hairs to stimulate the natural exit of the hair due to its exfoliating action.

• Action against the proliferation of bacteria, fungi, and viruses : Salicylic acid notably halts the proliferation of the bacteria responsible for the inflammatory reactions of acne, the Cutibacterium acnes, formerly known as Propionibacterium acnes. Moreover, due to this anti-microbial action, salicylic acid is often used as a preservative in cosmetic formulations such as foaming gels or emulsions.

• Soothing action : salicylic acid mitigates symptoms related to inflammation. Indeed, it intervenes in the arachidonic acid cascade and inhibits the synthesis of prostaglandins E2, molecules responsible for inflammatory and painful effects. In the treatment of acne, it thus soothes painful spots and visibly reduces redness.

• Regenerative action : Salicylic acid stimulates the synthesis of type I collagen, thereby reducing signs of ageing such as wrinkles and fine lines.

• Sebum-regulating action :Salicylic acid regulates sebum production allowing the pores to be unclogged, thus preventing the formation of comedones and blackheads.