AHA benefits for skin: what they do and how to use them

What do AHAs actually do?

AHAs dissolve in water and mainly work on the skin's surface. They loosen the substances holding surface cells together, allowing old cells to shed. Age and sun exposure slow this natural shedding, leaving a buildup that contributes to uneven texture. Removing those cells reveals skin with a fresher appearance and more even colour. Smoother texture and a more even tone are realistic goals, which is less dramatic than replacing your face and considerably more useful.12

Which skin concerns can AHAs help?

• Rough texture and dullness: shedding dead cells helps skin look smoother and brighter.
• Uneven tone and dark marks: glycolic acid helps lighten marks left by mild sun damage or acne.
• Fine lines and wrinkles: glycolic acid improves their appearance and stimulates collagen production. Collagen is a protein that gives skin structure and strength.
• Clogged pores and blackheads: glycolic acid removes dead cells and helps keep pores clear.
• Roughness with dryness: lactic acid acts as both an exfoliant and a moisturizer.

Should you choose glycolic acid, lactic acid or a BHA?

What AHA strength should you use?

Do not choose by percentage alone. Exfoliation depends on the acid type, concentration, pH and other ingredients. The pH describes how acidic or alkaline the formula is. Consumer safety criteria for glycolic and lactic acid products specify a concentration of 10 percent or less, a final pH of at least 3.5, and protection against increased sun sensitivity or directions for daily sun protection. A concentration below 10 percent is not the only condition that matters.4

How to introduce an AHA into your routine

1. 1Review your current products. Prescription retinoids, retinol and benzoyl peroxide can make skin more sensitive or cause peeling; adding exfoliation can worsen dryness or breakouts.
2. 2Test a small area first. For an AHA mask, check the ingredients and label before applying it across your face.
3. 3Apply gently and follow the product's directions. Leave on products and rinse off masks have different instructions. Do not exfoliate sunburned skin or skin with open cuts or wounds.
4. 4For glycolic acid, start once or twice a week at night. Increase frequency only if your skin tolerates it and the product directions allow it. Stronger exfoliation generally needs less frequent use.
5. 5Apply moisturizer after exfoliating. If you used a mask, wash it off as directed before moisturizing.
6. 6Use broad spectrum SPF 30 or higher sunscreen during the day. Reapply every two hours, wear protective clothing and limit sun exposure. Continue sun protection for a week after stopping an AHA.

Can you use AHAs with retinol or vitamin C?

When introducing glycolic acid, avoid combining it with retinol, vitamin C serums or other exfoliating acids. Introducing fewer active ingredients makes irritation easier to trace. AHA preparations can be alternated with retinoid creams or vitamin C rather than used together. Be especially careful with exfoliating masks if your routine already contains an acid or retinol.13

An AHA mask is an addition to cleansing, moisturizing and sun protection, not a promotion to head of the entire routine. Masks containing glycolic or lactic acid can help texture, clogged pores and fine lines, but a cosmetic mask does not replace acne treatment. Repeating an exfoliating ingredient you already use can trigger dryness and irritation rather than fill a gap in your routine.6

How long do AHA benefits take?

With glycolic acid products used at home, brighter skin and more even pigmentation can take several months of consistent use. Professional peels can produce more dramatic changes, while a series of superficial AHA peels retextures skin over a few months. Higher concentrations and longer use can also affect deeper skin layers, making fine lines less obvious. Do not increase the strength or frequency just because dark marks have not changed quickly.13

Who should be careful with AHAs?

Use particular caution with glycolic acid if you have dry or sensitive skin, rosacea, eczema, an active skin infection or skin that is not healing. Lactic acid is a gentler option, but strong AHA masks are unsuitable for sensitive skin. Avoid aggressive exfoliation if you have a darker skin tone or develop dark marks after acne, bites or burns: irritation can increase pigmentation. Low concentration glycolic acid is generally considered safe during pregnancy, but check with your healthcare provider before using it while pregnant or breastfeeding.35

When should you stop using an AHA?

Immediately wash off an exfoliating mask if you feel itching, burning or stinging. These can signal irritation or an allergy. Using masks too often can damage the skin barrier and cause dryness, irritation or breakouts. If your skin feels worse after a mask, see a dermatologist. Strong peeling products have also been linked to more serious reactions, including chemical burns, swelling and blisters.46

What are the skincare benefits of 30 percent AHA?

A 30 percent AHA peel aims at the same broad goals: smoother texture, more even tone and less obvious fine lines. The higher concentration changes the intensity of exfoliation, not the list of benefits. Professional glycolic peels use strengths from 20 to 70 percent, selected for skin sensitivity. Their application times should not be copied onto a home product. If you mean The Ordinary AHA 30% + BHA 2% Peeling Solution, it is a combined acid rinse off product with its own directions.14

The Ordinary directs you to use that peeling solution once or twice a week, ideally in the evening, on thoroughly clean, dry skin. Apply evenly with fingertips, avoiding the eye area, and rinse thoroughly with lukewarm water after no more than 10 minutes. Do not apply it to wet, sensitive, peeling or compromised skin; use only on unbroken skin. Patch test first. If irritation occurs, rinse off, stop use and consult a physician. Use sunscreen, protective clothing and limited sun exposure during use and for a week afterwards.7