Beauty Nerd: Alpha Hydroxy Acids


Hello again everyone! I thought I would start my first “ingredients” posts with the “ABC’s” of skincare ingredients– first up, Alpha Hydroxy Acids (AHAs). If you missed the first Beauty Nerd introductory post, make sure you read it here.

First, my disclaimer: Nothing I write in this series is medical advice and I will be writing from the perspective of a consumer interested in understanding how products work and if they are effective. If you have any medical questions, you should talk to your doctor!

What are they?

AHAs are organic compounds that contain a carboxyl group and one hydroxyl group at the alpha position (hence the name, Alpha Hydroxy Acids). Examples of AHAs include glycolic acid and lactic acid (the two most commonly used for cosmetic skincare results), citric acid, malic acid, and tartaric acid.

What are they used for?

In low concentrations (<10%), they are used in non-prescription topicals to exfoliate the skin to improve melasma, hyperpigmentation of the skin, texture, and fine lines.

In higher concentrations (20% to even 50 or 70%), they are used under the care of a dermatologist or other specialist to chemically “peel” the skin, treating calluses, keratoses, acne, psoriasis, and photoaging more drastically. (1)

How do they work?

The exact mechanism of AHAs still needs to be clarified. However, here are some of the most current theories:

  • AHAs may reduce the concentration of calcium ions in the epidermis (the outer layer of skin). Calcium ions play an important role in cellular adhesion, so when its concentration is reduced desquamation (shedding the outer-most layer of skin) can occur. (2)
  • AHAs may effect the secretion of cytokines (cell-signaling molecules) by keratinocytes (the predominant type of cell in the base layer of the epidermis). (3)
  • AHAs accelerate collagen synthesis by fibroblasts (the cells responsible for making connective tissue and collagen, in skin they are mainly in the dermis). (4) (5)

Special considerations:

AHAs increase skin sensitivity to UV– this means that you will be more sensitive to the sun while using these products. Always pair them with sunscreen every day to prevent further photoaging. (6)

Where can I find them?

I have had excellent results personally with AHAs in smoothing the texture of my skin as well as fading some light hyperpigmentation (combined with religious sunscreen use). Here are some of the products that I have personally tried and can recommend. Whenever I start with a new product, I use it once every 2-3 days (instead of daily) to make sure that it doesn’t irritate my skin.

I have also included one of my favorite facial sunscreens which has lactic acid in the formula.

There are definitely more products out there with AHAs in them (look for glycolic or lactic acid in the description or ingredients list)– I just haven’t tried them! I am interested in trying out Deciem’s The Ordinary Lactic Acid serum which is super affordable at under $7– I will update you guys once I get a chance to try it.

  1. Pixi Glow Tonic
  2. Pixi Overnight Glow Serum
  3. Drunk Elephant TLC Framboos Glycolic Night Serum
  4. Sunday Riley Good Genes
  5. Elta MD UV Clear SPF 46

So, have any of you tried products with AHAs in them? Any recommendations?

  1. Kornhauser A, Coelho SG, Hearing VJ. Applications of hydroxy acids: classification, mechanisms, and photoactivity. Clinical, cosmetic and investigational dermatology : CCID. 2010;3:135-142. 
  2. Wang X. A theory for the mechanism of action of the α-hydroxy acids applied to the skin. Medical Hypotheses. 1999;53(5):380-382.
  3. Rendl M, Mayer C, Weninger W, Tschachler E. Topically applied lactic acid increases spontaneous secretion of vascular endothelial growth factor by human reconstructed epidermis. British Journal of Dermatology. 2001;145(1):3-9.
  4. Okano Y, Abe Y, Masaki H, Santhanam U, Ichihashi M, Funasaka Y. Biological effects of glycolic acid on dermal matrix metabolism mediated by dermal fibroblasts and epidermal keratinocytes. Experimental Dermatology. 2003;12(s2):57-63.
  5. Bernstein EF, Lee J, Brown DB, Yu R, Scott EV. Glycolic Acid Treatment Increases Type I Collagen mRNA and Hyaluronic Acid Content of Human Skin. Dermatologic Surgery. 2001;27(5):429-433.
  6. FDA. Alpha Hydroxy Acids

2 thoughts on “Beauty Nerd: Alpha Hydroxy Acids

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