AHAs - Alpha Hydroxy Acids
What are they?
AHAs are alpha hydroxy acids - a class of chemical compounds that can be either naturally occurring or synthetic. Many are derived from organic sugars, with glycolic acid (from sugar cane) and lactic acid (from milk) the best-known and best-researched of the bunch.
What are they used for?
In over-the-counter products, AHAs offer chemical exfoliation as an alternative to manual exfoliation, working primarily by dissolving the bonds between skin cells to allow the removal of dead cells and a subsequently smoother skin surface. Low concentrations (from around four per cent) are usually gentle enough for regular at-home use, whilst chemical peels utilise concentrations of up to 70 percent under the supervision of a medical professional. Glycolic acid has the smallest molecule size, so is highly effective at penetrating the skin.
What are the pros and cons of using them?
AHAs certainly offer a smoother skin texture, and negate the use of harsh scrubs in those that prefer to avoid manual exfoliation. Since they act on the surface cells, they can reduce fine lines, dark spots and acne scars. Glycolic acid in particular can be used to treat oily and acne-prone skin, since it helps rid skin of the dead cells that cause blocked pores and trapped bacteria, eventually leading to spots. However irritation can occur, particularly in those with sensitive skin, so begin with a low concentration. AHAs also increase photosensitivity, so make sure to wear a sunscreen daily (although, beauty pupils, you should really be doing that anyway).
Which products can I find them in?
Peels aside, AHAs can appear in face washes, masks, serums and creams. Rinse-off products have less time to work their magic, so serums are often preferred since they can be directly applied to skin, have smaller molecules than creams and have longer in contact with the skin. For your AHA fix try Ren Glycolactic Radiance Renewal Mask, Sunday Riley Good Genes Treatment or Peter Thomas Roth Glycolic Acid 10% Moisturizer.