Walk through the skincare aisle and you will see glycolic acid, lactic acid, mandelic acid and salicylic acid on labels. They are all chemical exfoliants, and they are some of the most useful and most overused ingredients in skincare. Used well, they can smooth rough texture, brighten dull skin and help clear clogged pores. Used too often, they can leave skin red, stinging and darker than before.
This guide explains the difference between AHAs and BHAs, who each suits, how to start safely, and which Reginah products contain them.
What is chemical exfoliation?
Skin naturally sheds dead cells, but sometimes they build up and make skin look dull, feel rough or contribute to clogged pores. Exfoliation speeds up that shedding. The American Academy of Dermatology describes two broad methods: mechanical, which uses a brush, sponge or scrub, and chemical, which uses alpha or beta hydroxy acids (AHAs and BHAs) to dissolve dead skin cells. Which is best depends on your skin type.
Many dermatologists favour gentle chemical exfoliation over harsh scrubs, particularly for dry, sensitive or acne-prone skin, because it avoids friction. The AAD notes these skin types may do best with a washcloth and a mild chemical exfoliator.
AHA: the surface smoother
AHAs, such as glycolic acid and lactic acid, are water-soluble and work on the surface of the skin. They help loosen the bond between dead skin cells, which can improve texture, dullness and uneven tone.
- Glycolic acid has the smallest molecules among common AHAs, so it penetrates easily and can be effective but more irritating.
- Lactic acid is larger and often gentler, with some hydrating benefit.
- Mandelic acid is larger still and is often suggested for sensitive skin.
AHAs suit normal to dry skin, dullness, rough texture and fine lines. They are also found in body creams for rough patches.
Advanced Clinicals 10% Glycolic Serum 1.75oz Buy now
A 10% glycolic acid serum, listed as resurfacing to improve skin clarity, minimize pores and reduce fine lines. A stronger leave-on product, so start with once or twice a week.
Replenix Discoloration Glycolic Acid 10% Resurfacing Cream – 50g Buy now
A 50g resurfacing cream with 10% glycolic acid, according to its listing, made to exfoliate dead skin, fade discoloration and smooth texture.
BHA: the pore cleaner
The main BHA is salicylic acid. It is oil-soluble, so it can get inside pores and help clear blackheads and whiteheads, which is why it is a mainstay of acne products. BHA suits oily, combination and breakout-prone skin. Our full guide to salicylic acid for acne covers products and routines.
Garnier AHA + BHA with Charcoal Anti-Blemish Serum 30ml Buy now
A 30ml serum with 4% AHA and BHA, niacinamide and charcoal, listed as visibly reducing blemishes and smoothing skin texture.
Wash-off options
If leave-on acids feel intimidating, a wash-off product gives you contact time of just a minute or so.
Rejuva Skincare Duo Cleanse 5% Glycolic Acid + 2% Salicylic Acid 250ml Buy now
A 250ml professional exfoliating wash with 5% glycolic acid and 2% salicylic acid, according to its listing, made to clear pores and brighten texture. Because it combines two acids, use it only a couple of times a week to begin with.
You can browse more in our serums, skin treatments and scrubs and exfoliants collections.
Which should you choose?
| Concern | Start with |
|---|---|
| Oily skin, blackheads, breakouts | BHA (salicylic acid) |
| Dullness, rough texture | AHA (lactic or glycolic) |
| Dry or sensitive skin | Lactic or mandelic acid, low strength, once a week |
| Dark marks after breakouts | Gentle AHA or BHA plus sunscreen, used patiently |
| Rough elbows, knees and body | Body products with glycolic or lactic acid |
If in doubt, pick one acid and one product. You rarely need more.
How to start safely
- Patch test. Apply a small amount on the inside of your forearm or behind your ear for a few days before using it on your face. Our guide to sensitive skin explains how to patch test properly.
- Start once or twice a week. Use at night, on clean, dry skin.
- Apply a thin layer. More is not better.
- Moisturize afterwards. Exfoliation can be drying. Use a gentle moisturizer.
- Use sunscreen every morning. Acids can make skin more sun-sensitive. Our guide to the best sunscreen for dark skin is a good place to start.
- Increase slowly. If your skin is comfortable after a few weeks, add a night. Most people do well on two to four nights a week at most.
Combining acids with other actives
The AAD warns that retinoids, retinol and benzoyl peroxide can increase sensitivity or peeling, so using them alongside exfoliating acids may worsen dryness or cause breakouts. A safer pattern is to alternate nights: acid one night, retinol another, and rest nights with only moisturizer. If you are new to retinol, our beginner’s guide explains how to introduce it. Niacinamide and hyaluronic acid are usually good partners; see our guides to niacinamide and hyaluronic acid.
Darker skin tones: go gently
Aggressive exfoliation can irritate skin, and irritation can lead to post-inflammatory hyperpigmentation, especially in deeper skin tones. The AAD advises avoiding strong chemical or mechanical exfoliation if you have dark spots from burns, bug bites or acne, because aggressive exfoliation may increase pigmentation. Choose lower strengths, build up slowly and always wear sunscreen. Our guide on fading dark spots explains what helps more safely.
Signs you are overdoing it
- Redness, burning or stinging
- Tightness or shiny, “plastic” looking skin
- Flaking and peeling
- Sudden breakouts or rough patches
- Products you normally tolerate start to sting
If this happens, stop all exfoliants and active ingredients, keep your routine to cleanser, moisturizer and sunscreen, and let the barrier recover. It can take a couple of weeks. Our list of common skincare mistakes covers over-exfoliation.
Body exfoliation
AHAs also work on rough elbows, knees and arms. Body creams with glycolic or lactic acid can be gentler than scrubs for bumpy skin. Our guide to using a body scrub covers physical exfoliation, and our guide to body butter, lotion and oil explains how to moisturize afterwards.
When to see a dermatologist
See a dermatologist if you have painful acne, a persistent rash, burning that does not settle, or dark marks that do not improve with sunscreen and gentle care. Prescription options are available and a professional can assess whether exfoliating acids suit your skin.
Frequently asked questions
Can I use AHA and BHA together?
Some products combine them, but start with one. Using several exfoliating products in the same routine increases irritation.
Should I use acids in the morning or at night?
Night is more common, because acids can increase sun sensitivity. If you use them in the morning, wear sunscreen.
How often should I exfoliate?
Start with once or twice a week. Many people do well with two or three times a week. The AAD says the more aggressive the method, the less often you should use it.
Can I use acids if I have sensitive skin?
Possibly, with care. Lactic or mandelic acid at low strength, once a week, after a patch test, is a gentler route. If your skin reacts, stop.
Will acids remove dark spots?
They can help skin turnover, but they work slowly and need sunscreen. Dark spots can take months to fade.
Final thoughts
Chemical exfoliants can be transformative, but only if used gently. Choose the acid that fits your concern, start with one product, patch test, moisturize, protect from the sun and be patient.
Ready to start? Explore Reginah’s serums and skin treatments and pick one product to try.
