Alpha hydroxy acids (AHAs) are group of acids which help improve the skin because they have a chemically exfoliating effect. They work by dissolving the chemical bonds holding dead skin cells onto the surface of the skin. There several different AHAs and they vary in the strength and immediacy of their effects: glycolic acid is stronger, because it has a smaller molecular size, so it reaches more deeply into the skin, more swiftly; lactic and malic acids are more gentle as their larger molecules don’t penetrate the skin as deeply as glycolic acid can do. Citric acid and tartaric acid are two other examples of alpha hydroxy acids.
AHAs work to improve the texture and radiance of the skin by exfoliating the surface of the skin, which makes skin smoother, and by improving the hydration of the skin from within. Exfoliating the skin helps keep pores unblocked, so AHAs can also help to keep skin that tends to be spotty or congested, that bit clearer. AHAs also stimulate collagen formation in the skin so they can contribute to firming and strengthening the skin and reducing the appearance of wrinkles. By removing dead, pigmented skin cells from the surface they can help patchy pigmentation look more even, too.
AHA stands for Alpha Hydroxy Acid, so AHA exfoliants are skincare products that use the chemical exfoliation that lactic acid or glycolic acid can deliver, to improve the radiance, texture and hydration of the skin.
The skin is constantly renewing itself, with fresher layers being produced from within the dermis, and pushing up towards the surface of the skin as the outermost layers of cells die and are shed. However, the dead cells don’t always shed so easily. There are chemical bonds (you can think of them as a kind of celllar ‘glue’) holding the dead skin cells onto the surface of the skin. Alpha hydroxy acids can workl their way around these bonds and effectively dissolve the glue, which allows the outermost dead skin cells to be wiped or washed off of the face, revealing the fresher, brighter skin underneath.
This depends on the formulation your alpha hydroxy acid is in. Whichever product you are using, follow the directions on the packaging.
Some AHA exfoliants are cleansers, in which case you use them like a regular cleanser and wash them off. Some, however, are leave-on (such as toners or creams) – these you use after cleansing. If your AHA product is an ‘acid toner’, apply it to a cotton pad and wipe it over your face. If it’s in a cream, use this like any other face cream – although I’d be careful around your eyes.
Glycolic acid is a type of alpha hydroxy acid. So glycolic acid is an AHA, but there are more types of AHA than just glycolic acid. While the alpha hydroxy acids are generally quite similar in terms of the benefits they confer on your skin, glycolic acid in particular has the added benefit of boosting collagen levels in the skin – which is very helpful for aging and wrinkling skin, as collagen is the protein that keeps skin firm.
No! In fact, they do the reverse. There are two reasons why you may have heard that they accelerate aging, but neither of these is actually correct.
The first of these is that you may have heard people say that alpha hydroxy acids ‘thin the skin’. That doesn’t sound like a good thing, does it? Thin skin can wrinkle more easily, so if AHAs actually did thin the skin, then you would be absolutely right that this would be a problem. The thing is, they don’t. While they thin the upper surface very slightly (because they’re getting rid of the outermost cells, which are dead anyway), they actually thicken the dermis (the lower layers of the skin). They manage to do this by supporting and hydrating these lower layers of the skin, and stimulating collagen production in them. So no, alpha hydroxy acids don’t thin the skin. Using AHAs will, over time, make skin thicker and firmer.
The second reason is that in the early 2000s, a study by the European Commission’s Scientific Committee on Cosmetic Products revealed that a number of studies had shown that alpha hydroxy acids appeared to lead to an increase in damaged skin cells, and cause reddening, blistering and burning of the skin as well as making it more vulnerable to UV damage. However, according to leading dermatologists, this was down to consumers not using the products properly – using them too frequently, using them improperly, and using them even when their skin was too sensitive to deal with the products. There’s no longer this sort of concern around AHA use, but I’d still advise you to be sensitive to how your skin responds to whichever products you’re using, and to keep this in mind when choosing how frequently to use your desired products. Even if you love the glow they give your skin, don’t overuse them.
That said, alpha hydroxy acids do make your skin more sensitive to sunlight and the potential for photo-aging – so while they’re great anti-ageing ingredients, you do need to step up and use a sunscreen every day (if you weren’t already). If you do this, then AHAs absolutely won’t accelerate ageing.
Yes – check the label for the expiry date of your products. All beauty products, by law, have a symbol on the packaging to show how long they will last for once they’ve been opened. Your product may well be safe to use longer than this suggests, but it may not be fully effective.
