What does AHA mean?

Which ingredients are AHAs?

Glycolic acid and lactic acid are common AHAs in skincare. Citric acid, malic acid and tartaric acid also belong to the group. AHA describes a family of ingredients, rather than one specific acid or product. The abbreviation is shorter than the name, which is one small courtesy from skincare packaging.12

These acids occur naturally in foods such as sugar cane, milk and fruit, but AHAs used in cosmetic products are usually made synthetically. A food origin is not a measure of how gentle a finished product will be.2

What do AHAs do for skin?

AHAs help remove old surface cells, improving the appearance of uneven texture and colour. Regular applications can improve fine lines and brown marks. Glycolic acid can also help skin prone to acne. These are uses for the ingredient group, not reasons to expect every AHA product to deliver the same results.1

Glycolic acid has smaller molecules than other AHAs and penetrates skin more easily. Lactic acid is one of the gentler options and acts as both an exfoliant and a moisturizer. It can be a better starting point for sensitive skin. Lactic acid also appears in body products for rough bumps caused by a buildup of dead skin around hair follicles.34

Is AHA the same as BHA?

No. AHAs dissolve in water and mainly exfoliate the skin's surface. BHAs, or beta hydroxy acids, dissolve in oil and reach deeper into pores. Salicylic acid is the common skincare BHA and helps remove the oil that contributes to clogged pores, blackheads and whiteheads. Hyaluronic acid is neither an AHA nor a BHA; its role is hydration rather than exfoliation.4

Does a higher percentage mean a better product?

Concentration matters, but so do the product's pH, meaning its acidity, and how long it stays on your skin. An AHA product is a formulation, not a percentage wearing a cap. A product you rinse off and one you leave on do not give the acid the same contact time. Professional peels use higher concentrations than typical home glycolic acid products.23

How do you start using an AHA?

1. 1Test a small amount on one area first, especially if you are starting glycolic acid.
2. 2Follow the product's directions. For glycolic acid, start once or twice a week at night and increase frequency only if your skin tolerates it.
3. 3When starting glycolic acid, avoid using it alongside other exfoliating acids, retinol or vitamin C serums.
4. 4Use broad spectrum SPF 30 or higher sunscreen during the day, and reapply every two hours.

Who should be careful?

Be cautious with glycolic acid if you have sensitive or dry skin, rosacea, eczema, an active skin infection or skin that is not healing. Low concentration glycolic acid is generally safe during pregnancy, but check with your healthcare provider before using it while pregnant or breastfeeding.3

AHAs can cause redness, swelling, burning and itching. Stop using an exfoliating product if your skin becomes too dry or irritated rather than applying more or using it more often.25

How long do results take?

Home glycolic acid products can take several months of consistent use to produce noticeably brighter skin or more even pigmentation. Professional peels generally produce more dramatic changes, but they are a different treatment from a home exfoliant.3