Alpha hydroxy acids

What do they do?
Chemically exfoliate skin, lifting off dead skin cells
Promote collagen remodelling
Improve skin hydration

Why should I use them?
Skin brightening and smoothing
Fine lines and wrinkles
Keratosis pilaris

How do I use them?
Apply at night one to three times per week, followed by moisturiser.
Always use sunscreen during the day.

Evidence rating


Alpha hydroxy acids are fantastic all-rounders to add to your skincare routine. There are a few types available, so most people can find one that suits their skin. 

What are alpha hydroxy acids and how do they work?

Alpha hydroxy acids are a group of compounds which chemically exfoliate the top layers of the skin, which means they help remove dead skin cells from the surface of the skin, revealing brighter looking skin. When used at higher concentrations, they can assist with collagen remodelling, which means they can help stimulate new collagen production and tighten existing collagen fibres. This can reduce the appearance of fine lines and wrinkles. They also help to improve pigmentation and acne, and may increase the penetration of other active skincare ingredients, making them more effective. In addition, they’re also humectants, helping the skin to retain moisture and feel more hydrated. 

Alpha hydroxy acids are water soluble, so work more superficially in the skin than oil soluble beta hydroxy acids. They’re available as cleansers, leave-on preparations, and as chemical peels

What types of alpha hydroxy acids are there?

The most commonly used alpha hydroxy acids are glycolic acid and lactic acid. Others include citric acid, malic acid, mandelic acid and tartaric acid. Glycolic acid is the most effective but also the most irritating, then comes lactic acid. Mandelic acid is the most gentle, but it’s not quite as powerful as glycolic and lactic acid. 

Why should I use them? 

Alpha hydroxy acids are great for skin brightening and smoothing, hyperpigmentation, fine lines and wrinkles, acne and keratosis pilaris

What should I look for in a product? 

Concentrations: 4-10% in cleansers and leave-on preparations, higher concentrations may be used in chemical peels.  

pH: alpha hydroxy acids must be formulated at a pH of 3-4 to be effective. 

How should I use them?

It’s best to apply alpha hydroxy acids at night, as they can increase sun sensitivity. Begin by using them one to two times per week to avoid irritation, and build up to alternate nightly or nightly use if desired. If you have sensitive skin, consider starting with mandelic acid or lactic acid, rather than glycolic acid. Many people alternate use of their alpha hydroxy acid with a retinoid, as the two can be more irritating if applied at the same time. After applying your alpha hydroxy acid, it’s a good idea to apply a moisturiser.  

What are the issues to consider? 

Alpha hydroxy acids may cause skin irritation and photosensitivity, so apply them at night and start slowly. If you’re prone to irritation, consider starting with mandelic acid which is one of the most gentle forms. Once you’re tolerating that, you could try lactic acid, and then glycolic acid. 


If you find you’re developing skin irritation such as redness, stinging or dryness, consider:

  • using your alpha hydroxy acid less often,
  • finding a product with a lower concentration,
  • changing to a more gentle form such as mandelic acid, and
  • making sure you apply moisturiser afterwards. 

Moghimipour E. Hydroxy Acids, the Most Widely Used Anti-aging Agents. Jundishapur J Nat Pharm Prod. 2012;7(1):9-10.

Tang SC, Yang JH. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. 2018;23(4):863. Published 2018 Apr 10



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Spotlight on Skin was created by award-winning Melbourne-based dermatologist, Dr Julia Rhodes.

Julia knows first-hand how overwhelming the skincare world can be, and that’s with over 10 years of experience practicing dermatology. Given that even she gets overwhelmed, she appreciates how hard it can be for those of you without a scientific background to make sense of all the information available, and choose products that are right for your skin…