What is an AHA exfoliant?

What does an AHA exfoliant do?

AHAs are water soluble acids, meaning they dissolve in water rather than oil. They encourage the shedding of old surface cells without needing a scrub. As skin ages and accumulates sun exposure, those cells leave the surface more slowly. Helping them shed can improve rough texture and uneven colour.14

AHA products are sold for texture, tone and fine lines, which gives one exfoliation job quite an extensive CV. Glycolic acid can improve the appearance of fine lines and dark spots from mild sun damage or acne. With prolonged use, glycolic acid can also stimulate collagen, the protein that gives skin structure and support. Not every AHA product has the same strength or effect.245

Which ingredients are AHAs?

Glycolic acid and lactic acid are the most common AHAs in cosmetics. Other examples include citric, malic and tartaric acids. Glycolic acid has smaller molecules than other AHAs and penetrates skin more easily. Lactic acid is gentler and acts as both an exfoliant and a moisturizer. Finding an AHA on an ingredient list does not automatically make the product an exfoliant: an acid can also be included to adjust pH, the measure of acidity.1245

What strength should you use?

The percentage is only part of the answer. Exfoliation also depends on the particular acid, the product's pH and the other ingredients. Two products with the same acid percentage are not necessarily equally strong. For consumer glycolic and lactic acid products, safety criteria include a concentration of 10 percent or less, a final pH of at least 3.5 and protection or directions addressing increased sun sensitivity. These are safety conditions, not a reason to begin at 10 percent.5

A leave on cream and a rinse off peel are both AHA formats, not competing personality types. Their directions matter: some products stay on the skin, while others require thorough rinsing after a short application. Professional glycolic peels use much higher concentrations, sometimes 20 to 70 percent. Do not copy a professional peel's strength or application method into a home routine.13

How do you start using an AHA exfoliant?

1. 1Test a small amount on one area before applying glycolic acid more widely. Watch how your skin reacts before continuing.
2. 2Use a leave on AHA at night and follow its application and rinsing directions. For glycolic acid, begin once or twice a week. Increase frequency only if your skin tolerates it and the label allows it.
3. 3Apply moisturizer afterwards to help manage dryness. Do not apply extra exfoliant to dry or peeling areas.
4. 4Use sun protection the next day and throughout your use of the product. Keep protecting your skin for a week after stopping.

When introducing glycolic acid, avoid using it alongside other exfoliating acids, retinol or vitamin C serums. Starting with fewer active ingredients reduces irritation risk and makes a reaction easier to trace. Once established, AHA products can be alternated with retinoid creams or vitamin C rather than putting everything into the same application. If a retinoid is prescribed, check how an AHA fits your treatment before adding it.14

Why does sunscreen matter with AHAs?

AHAs increase skin sensitivity to ultraviolet light, raising the possibility of sunburn. Nighttime application does not remove that daytime risk. Use broad spectrum sunscreen with SPF 30 or higher, wear protective clothing and limit sun exposure. Reapply sunscreen every two hours when exposed to the sun. Continue these precautions for a week after your last AHA application, because increased sun sensitivity can persist after you stop.34

How long does an AHA exfoliant take to work?

For brighter skin or more even pigmentation, an ordinary glycolic acid product can take several months of consistent use. Professional peels can produce more dramatic changes, but are a different treatment from a home exfoliant. Regular AHA applications can improve fine lines and brown marks over time. Increasing frequency beyond your skin's tolerance is more likely to cause irritation than make a useful shortcut.146

How do AHA and BHA exfoliants differ?

Should you use an AHA or BHA exfoliant?

Choose an AHA when surface roughness, uneven colour or fine lines are your main concern. Salicylic acid is the more direct choice when blackheads, whiteheads and oily clogged pores are the priority. The categories overlap: glycolic acid can also help unclog pores. Choose by the problem you want to address rather than assuming one acid family is better for every face.24

Can you use an AHA exfoliant on sensitive skin?

Lactic acid is a gentler option for sensitive skin, but an AHA can still irritate. Be particularly cautious with glycolic acid if you have dry skin, rosacea, eczema, an active infection or skin that is not healing. If your skin is already dry and peeling, moisturize instead of exfoliating. Creams and ointments retain more moisture than lotions and are better choices for dry skin.247

Stop the exfoliant for a few days if your skin becomes too dry or irritated. Burning, rash, swelling and blisters are reported AHA reactions, not results to pursue. See a dermatologist if dryness worsens or becomes painful, cracked, bleeding, stinging or very irritating.567

Low concentration glycolic acid is generally considered safe during pregnancy. If you are pregnant or breastfeeding, check with your healthcare provider before using it.4

Can an exfoliant contain both AHA and BHA?

If an ingredient list includes glycolic or lactic acid alongside salicylic acid, it includes both acid families. That does not mean you need both. When starting glycolic acid, avoid adding other exfoliants, including salicylic acid, and follow the product's directions rather than building a separate acid combination.245