Alpha Hydroxy Acids for Skin: The Complete Guide

Alpha Hydroxy Acids
Glycolic Acid
Lactic Acid
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Alpha Hydroxy Acids for Skin: The Complete Guide

It's been a while since acids stormed the skincare world, and truth be told, our beauty routines are incomplete without them. Manual exfoliation on the face and neck is so passé. Who needs that when we have chemical acids that exfoliate gently to reveal smoother, softer skin? Alpha hydroxy acids (AHAs) overcame manual exfoliation and are here to stay since they're good at tackling pretty much all skincare concerns.

AHAs superficially peel the skin, buffing away dead cells buildup. By removing old cells, new healthy cells take their place. Consequently, AHAs reveal smoother texture, evener tone, diminish dark spots and acne scars, and keep a dull appearance at bay, making your skin feel brand new. But how much do you really know about the skin benefits of alpha-hydroxy acids?

What are Alpha Hydroxy Acids?

AHAs are water-soluble compounds derived from natural sources, such as fruits and milk — glycolic acid (sugar-cane derived) and lactic acid (from milk), being the best known AHAs. Since AHAs are water-soluble, they act mainly on the skin's surface, exfoliating the skin with minimal risk.1

Alpha-hydroxy acids have similar chemical structures, yet they work differently due to various molecular sizes and diverse properties. "The smaller the molecule, the deeper the penetration, and therefore, the more efficacious it is," says Marnie Nussbaum, MD, a New York City dermatologist.2

On the other hand, though, the chances of inflammations and irritations increase once with efficacy and penetration depth. Rest assured, you're about to find out how to use AHAs the right way to dodge irritations.

What are the skin benefits of Alpha Hydroxy Acids?

The skin benefits of alpha-hydroxy acids are endless. They go from unclogging pores and diminishing breakouts to fading hyperpigmentation to promoting collagen and hyaluronic acid production and improving firmness.3

AHAs have many perks to offer through a simple step of peeling away the top skin layer consisting of dead cells, debris, impurities, sweat, and dust while encouraging cell turnover. 

Alpha-hydroxy benefits for skin

  • Shed away dead cells
  • Enhance collagen production
  • Brighten tone
  • Unclog pores
  • Prevent pimples and blackheads
  • Increase products absorption

How to Use Alpha Hydroxy Acids in Your Skin Care Routine

Excluding peeling solutions, AHAs are added to all sorts of skincare products. Leave-on products allow acids to work more, and among all, serums are the most beneficial due to their small molecules that help active ingredients enter beneath the skin surface. Nevertheless, the most effective at stimulating cell turnover and shedding dead skin cells are AHA peels, either in a solution or pads-soaked.

AHA peels are serious business, and to stay on the safe side, use them with extra care. Upfront, you shouldn't use an AHA peel more often than twice a week. The skin needs time to regenerate, and overusing AHAs might damage the skin barrier, causing irritations and inflammations. So don't push for dramatic results; just give it time. 

Also, mixing AHAs with other actives like retinol, vitamin C, scrubs, and benzoyl peroxide, is a no-no. For the best, alternate the time of the day or the day you use them to reap most of the benefits and avoid irritations.

If you've never used AHAs before, begin with a low concentrated product and gradually go up to 10%, the maximum allowed by the FDA for home use.4

You could start with lactic acid since it's the gentlest one, then go for stronger peels with glycolic acid. Speaking of, do you know what the difference between lactic acid and glycolic acid, the two main pillars of AHAs, is?

Glycolic Acid vs Lactic Acid

Even if they're part of the same family, glycolic acid and lactic acid act differently, mainly due to their molecular sizes. Whilst glycolic acid has a small molecule allowing it to go beneath the skin's surface, lactic acid's molecular weight is larger, making the acid work on the top skin layer, hence is gentler. As such, lactic acid is a better choice for dry, sensitive, and mature skins.

Another reason lactic acid works better for these skin types is its humectant activity, meaning the capacity to bind water to the skin and promote moisture retention.5

On the flip side, glycolic acid is more suitable for oily and acne-prone skin types thanks to its antibacterial and sebum-balancing activities.6

What are the Potential Side Effects of Alpha Hydroxy Acids?

Even if AHAs peel the skin superficially, they can still cause redness, irritations, itching, and swelling in rare cases. Usually, things can go awry if an AHA facial peel is left on the skin longer than recommended or used too often. At the same time, "we conclude that whether AHA is a friend or foe of human skin depends on its concentration." [1] Meaning, start with a low concentrated product and gradually work up to higher concentrations, allowing your skin to adjust to AHAs and hinder possible side effects.

Find the Best Alpha Hydroxy Acids Products for You

At Exponent, results come first. We're happy to announce that, coming soon, you'll have access to the first self-activated skincare line inspired by our Full Of Standard. Until then, use our Product Recommendation List to find the best alpha-hydroxy acids-infused skincare, clinically proven products that are active, not acting.

Words By: Ana Vasilescu


  • Tang SC, Yang JH. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. 2018. Source
  • Here's Why Dermatologists Say Alpha Hydroxy Acids Are the Best Exfoliant. Byrdie. January 2022. Source
  • Tran D, Townley JP, Barnes TM, Greive KA. An antiaging skin care system containing alpha hydroxy acids and vitamins improves the biomechanical parameters of facial skin. Clin Cosmet Investig Dermatol. 2014. Source
  • Alpha Hydroxy Acids. FDA. August 2020. Source
  • Barbara Algiert-Zielińska MSc. Lactic and lactobionic acids as typically moisturizing compounds. Wiley Online Library. September 2018. Source
  • Valle-González ER, Jackman JA, Yoon BK, Mokrzecka N, Cho NJ. pH-Dependent Antibacterial Activity of Glycolic Acid: Implications for Anti-Acne Formulations. May 2020. Source


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