Guest blog: Alpha hydroxy acids thin the skin, don’t they?

This week's guest blogger, Lorna Bowes, director of skincare distributor Aesthetic Source, busts the myths about using AHAs in a skincare regime

This is a fascinating myth and comes from a complete misunderstanding of the anatomy of the skin and of how AHAs work, which dates back some twenty years.

There are many published clinical papers on the science, efficacy and safety of AHAs, and most describe clearly how they work. In short, they show that regular treatment with AHAs has two different effects on skin thickness. Now, we all know that as we age, the stratum corneum becomes thickened and rigid, which doesn’t look great, but total skin depth tends to reduce, which lead to wrinkling and skin that appears fragile. AHAs actually address both of these issues.

Firstly, AHAs have been shown to normalize the stratum corneum, by speeding up the shedding of the stratum corneum, refining this outer layer of the skin. As we know, this is a good thing.

One clinical paper looked at potential increase in sun sensitivity with regular use of AHAs and established clearly that an SPF of just 2 is enough to mitigate this. And I would of course recommend a far higher SPF to all clients, whether or not they were using AHA-based products.

Secondly, studies have shown that AHAs actually thicken the skin, increasing thickness of the epidermal and the deeper papillary dermal skin tissue. They have also been proved to improve the quality of elastin fibres, improve the density of collagen and promote the production of glycosaminoglycans (GAGs), which plump up skin from the deeper, dermal layers and smoothes wrinkles from the inside out.

So why do people still repeat this myth? Well, once something is published in consumer press, it tends to be repeated time and again. So one journalistic report that AHAs thin the skin printed in a national paper twenty years ago (the misunderstanding that came from a clinical paper describing the refining of the stratum corneum) became ‘AHAs thin the skin’ and rebounds today to confuse our clients.