Everything you need to know about PHAs.

Polyhydroxy acids are second-generation AHAs (alpha hydroxy acids). They exfoliate dead skin cells which build up on the surface of the skin, to brighten the complexion and tighten pores. This chemical desquamation, or peeling effect, also helps ingredients in other skincare products to more deeply penetrate the skin, improving their effectiveness.

The three PHAs most commonly used in cosmetics are:

• Gluconolactone or gluconic acid is a PHA that is naturally present in skin cells. It’s an antioxidant, and is very effective against inflammation ;

• Galactose is also naturally present in the body. Its role is to stimulate collagen production ;

• Lactobionic acid is derived from lactose, and has a hydrating and soothing effect.

PHAs are real allies in maintaining healthy skin, with multiple benefits and working in different ways to exfoliate imperfections and brighten dull and tired complexions:

• PHAs are known for their keratolytic effect. They help to get rid of dead skin cells that block pores, and smooth your skin’s texture by dissolving intercellular bonds and stimulating skin cell renewal. This is known as chemical exfoliation. They help to prevent the appearance of blackheads and slow the signs of ageing, such as fine lines and wrinkles.

• Several studies have shown their anti-inflammatory properties. PHAs are especially effective on oily skin which may be prone to breakouts and/or which has pigmentation marks caused by post-inflammatory hyperpigmentation.

• PHAs are also hydrating: they capture and retain water in the skin to reduce skin dryness by half.

• Finally, they fight against glycation, a biological process which causes degradation of elastin and collagen, both of which are essential proteins that keep skin firm and plumped.

PHAs are smaller molecules than AHAs (glycolic acid, citric acid and lactic acid) and BHAs (salicylic acid), so they penetrate less deeply into the skin and are generally better tolerated by all skin types, even the most sensitive which can’t use AHAs and/or BHAs.