Alpha Hydroxy Acid better known as AHA is a class of mild chemicals used to exfoliate skin. AHAs that are typically purchased over the counter are not going to give an immediate glowing appearance. In general they’re found at less than 10% concentrations and provide a more long term exfoliation need. With long-term use, AHAs can also help to increase skin firmness and decrease the appearance of sun damage, and fine wrinkles.
AHAs are something I would suggest people add to their beauty regiment when they begin to build one. I started to build a ‘beauty regiment’ in my teens and part of that beauty habit was using an AHA and BHA once per week. That was roughly 20 years ago and formulations have improved significantly in that time. AHAs aren’t as irritating and their delivery system has greatly improved as well as their price point meaning using a lowers concentration for everyday is more feasible. I’d highly suggest a lower dosage AHA everyday versus a once a week higher dose from mask like Peter Thomas Roth’s Pumpkin Enzyme Mask.
All AHAs are water soluble, were originally derived from plants, and are mildly acidic having a pH between 3.5 and 4.1. So they aren’t strong acids but also not something you want to put at full concentration on your face. As such we use AHAs at a 2-10% solution for everyday use and up to a 70% AHA solution for a dermatologic facial peel. At home facial peels use a 30% AHA.
AHAs contain several acids, it isn’t just one. From most active to least active:
- Glycolic Acid
- Lactic Acid
- Malic Acid
- Tartaric Acid
- Citric Acid
- Ascorbic Acid
- Mandelic Acid
The most common AHAs used in the beauty industry are Glycolic, Lactic, and Malic Acids and in that order. Glycolic and Lactic acids are smaller molecules that penetrate the skin well and effectively to exfoliate the top layer of skin. Long-term use of AHAs is considered safe but photosensitivity may occur for some so sunscreen is highly recommended when using AHAs during the day.
Precisely how AHAs work isn’t well understood. We do know AHAs are water soluble meaning they work more on the surface of the skin than into pores where sebum (oils) are going to prevent penetration into the pore. Based on current research, AHAs breakup cell to cell bonds making it easier for skin cells to be dislodged and removed via washing. With long-term use AHAs can also increase skin thickness, increase collagen synthesis, and increase elasticity. All this equals a decrease in fine lines and wrinkles with long-term use. AHAs have to remain on the skin for a period of time for them to work. How long depends on which AHA is being used and the concentration of that AHA. Glycolic Acid is the smallest of AHA and will take less time than Citric Acid or Mandelic Acid. Using a facial soap with AHA in it is not advised because the ingredients aren’t on the skin long enough to do anything; for most people cleansing soap is on the skin no longer than 2 mins. However using AHA in toners and serum is a very effective delivery method.
Glycolic Acid
The most commonly used AHA. It is also the smallest molecule size making the best absorbed of the AHAs. Because it’s the most commonly used AHA it also happens to be the best studied.
Most often found in concentrations up to 5% but easily found and widely available at concentration of 10-30%, glycolic acid is one of the more active AHAs due to its smaller size. It’s also the best studied. Glycolic Acid has been found to aid in decreasing the appearance photoaging after 22 weeks using an 8% glycolic solution.
Glycolic acid of 30% or more have also been used successfully to decrease the appearance of acne scarring and hyperpigmentation in Asian and Indian skin types.
Final Thoughts
When using AHAs, it is important to continue to use sunscreen as AHAs can increase tanning in Asian and Caucasian women. This study shows the importance of wearing sunscreen when we go outdoors especially when trying to decrease sun damage and prevent wrinkles, which is part of the reason you’re using AHAs.
1. Use Sunscreen
2. Avoid marketing gimmicks of soaps that contain AHA, you’re wasting your money there.
3. If you have acne scaring a glycolic acid peel using a 30% GA peel can do wonders longterm for your dark spots.
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