Chances are, if you have a developed skin care routine or just venture out to try new products, you have used something on your skin that contains a hydroxy acid. Hydroxy acids provide versatile skin benefits like brightening, smoothing, firming and clearing skin, but how do they work? Hydroxy acids work to deeply cleanse and remove impurities from the skin by exfoliating dead skin cells for an even, more vibrant complexion. With that being said, there are three categories of hydroxy acids that are derived from different sources.

Alpha Hydroxy Acids

AHA’s are water soluble and often derived from “fruit acids” to exfoliate and smooth skin. The following includes the specific types of AHAs, where they come from and what they do.

  1. Mandelic Acid

Mandelic acid is a naturally occurring acid found in bitter almonds and wild cherries.

Compared to the other AHAs, mandelic acid holds a larger molecular weight which allows it to provide more exfoliation with less irritation. This makes it the perfect hydroxy acid for someone with more sensitive skin as it doesn’t trigger a post-inflammatory response. It deeply removes excess oil and dead skin build up within the pores to clear and even complexions.

  1. Glycolic Acid

This is yet another naturally occurring acid derived from sugarcane, deemed by many experts as the most effective hydroxy acid. Glycolic acid is the smallest acid molecule, making it easier and more effective to penetrate the skin in the deepest and fastest way possible for optimal benefits. Glycolic acid effectively exfoliates the skin and even works to combat signs of aging and discoloration. This effect makes it the most beneficial for those with less sensitive skin who experience wrinkles, fine lines and skin discoloration.

  1. Lactic Acid

Naturally occurring in sour milk, this acid works to exfoliate the skin while also deeply hydrating. Being a larger molecule, it provides a gentler application while still clarifying pores. The fact that it is gentler than glycolic acid makes it better for those who get easily irritated skin but still want an exfoliant. Lactic acid can also help improve the skin’s firmness while also combating fine lines and dark spots for a brighter, more vibrant complexion.

Beta-Hydroxy Acid

BHAs are similar to AHAs when it comes to their effects on the skin however, BHAs are lipid soluble instead of water soluble like AHAs. This means it can penetrate deeper into the skins outer-most layer and effectively exfoliate.

  1. Salicylic Acid

This is the most common BHA and it is derived from the rich bark of the willow tree. Different from AHAs, BHAs are most effective in treating breakouts and acne-prone skin. This acid is less irritating on the skin while also working to deeply clarify pores by breaking apart debris, dirt and oil that can get stuck within your pores and result in breakouts. It works to tackle existing breakouts while also preventing future ones.

Polyhydroxy Acids

This hydroxy acid is often portrayed as a “new” AHA and contains gluconolactone, galactose and lactobionic. It provides the skin with similar exfoliation benefits as AHAs while also containing antioxidants that help protect the skin from environmental stressors and UV damage while also deeply moisturizing. PHAs are perfect for sensitive skin as they are a larger molecule and gentler on the surface.


Tolentino, Gracee. “Hydroxy Acids: What They Do and Which Ones Are Right for You.” Dermstore Blog, Dermstore Blog, 12 May 2020, —READ MORE

Tang, S. C., & Yang, J. H. (2018). Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules (Basel, Switzerland)23(4), 863. —READ MORE

Moghimipour E. (2012). Hydroxy Acids, the Most Widely Used Anti-aging Agents. Jundishapur journal of natural pharmaceutical products7(1), 9–10.

Kornhauser, A., Coelho, S. G., & Hearing, V. J. (2010). Applications of hydroxy acids: classification, mechanisms, and photoactivity. Clinical, cosmetic and investigational dermatology3, 135–142. —READ MORE


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