Alpha Hydroxy Acid (AHA)

When considering using glycolic acid on your skin it’s essential to understand what alpha hydroxy acids are and how they work.

What are alpha hydroxy acids?

Alpha hydroxy acids (or AHAs) essentially originate from milk and fruit sugars. The most common alpha hydroxyl acids are lactic acid and glycolic acid. These two acids in particular penetrate the skin very well and are often used in skin care products. As well, there is a good deal of scientific data on both acids, both on their effectiveness (how well they actually penetrate the skin to give the desired result) and their relevant side effects.

While you have likely heard of lactic acid and glycolic acid, there are three others: Malic acid, citric acid and tartaric acid.

How do alpha hydroxy acids work?

The main benefit of an alpha hydroxy acid is its ability to exfoliate the skin. They essentially remove the “glue” from the upper layer of skin that holds onto the old, dead skin cells. By effectively removing that top layer of skin, the alpha hydroxy acids serve to help new skin grow.

Alpha hydroxy acids reduce the look of wrinkles, help to reduce the likelihood that winkles will develop, make skin smoother and (with months of daily use) can help skin that’s uneven and hyper pigmented become smoother and more even.

It’s also believed that in addition to helping new (younger looking and fresh) skin to grow, alpha hydroxy acids also stimulate the growth of elastin and collagen, both of which become depleted with age.

Though some people with very sensitive skin might have a hard time using alpha hydroxy acids with any regularity, most people can use them once they discover what the right concentration is for their particular skin. Alpha hydroxy acids seem to work best for most people in a concentration of 5% to 7%, and that’s the concentration found in most products that contain the AHAs.


Though AHAs are safe to use on skin, there are some guidelines set forth by the Food and Drug Administration for its use. They include the stipulation that the product containing AHAs contain a concentration of 10% or less of the AHA.

When you use an alpha hydroxy acid product, you make your skin more vulnerable to damage from the sun. It’s recommended that if you use an AHA product, you also use a high-quality sunscreen to protect your skin from the sun. To that end, the FDA also recommends that products containing AHAs either contain sunscreen, or a warning telling users to use sunscreen while using the product.

What are the side effects?

There are two major side effects to using AHA products: sun sensitivity and irritation.

Though we have already discussed sun sensitivity, it’s important to reiterate that point. AHA products can increase your sensitivity to the sun by as much as 50%, so it’s essential that a good sunscreen is used.

Irritation is another possible side effect of Alpha Hydroxy Acid use. Some of these symptoms might include redness, burning and itching. If the symptoms continue after you have used the product for some time and your skin has had a chance to adapt, try using a product that contains less of the AHA concentration.