Glossary

This group of acids includes, amongst others, glycolic, citric, lactic, malic, mandelic and tartaric acid. Because they can be found naturally in certain fruits, AHA have already been used since ancient times for cosmetic purposes. They can found in free, salified and ether forms. AHAs have the capacity to destroy the bridges that bind epidermis cells together, in particular in the stratum corneum. In free form (glycolic acid, lactic acid), they penetrate 1000 more that in salified form (sodium glycolate, ammonium lactate). In free form, they are used for their exfoliating properties (via the reduction of the cohesion of corneocytes). In their salified form, for their moisturising properties (via the increase in the stratum corneum's capacity to retain water). Certain salified AHAs are part of the NMFs (Natural Moisturizing Factor) present in the stratum corneum and are capable of increasing the content in water of the epidermis' superficial layers. AHAs also act on the dermis by increasing the proliferation of fibroblasts, the synthesis of collagen, mucopolysaccharides and hyaluronic acid. On their own or in combination with molecules that specifically lead to depigmentation, AHAs lighten the complexion thanks to a better dispersion of melanin in the epidermis and a curbing action on the enzyme responsible for the synthesis of melanin (tyrosinase).
AHA and sun: Because they reduce the thickness of the stratum corneum, AHAs can increase the effects of UV rays on tanning as well as on sunburn.
AHA and ageing: On their own or combined with other active ingredients, AHAs can repair skin damage caused by ageing.