Exfoliating acids: AHA, BHA and PHA explained

2026-09-25 Cathy Molenaar

Exfoliërende zuren: AHA, BHA en PHA uitgelegd

Exfoliating acids loosen the bonds between dead skin cells, so your skin looks more even and fresher. There are three families: AHAs such as lactic acid and citric acid (water-soluble, for the skin's surface), BHA such as salicylic acid (oil-soluble, down into the pore) and PHAs such as gluconolactone (the mildest, with a larger molecule).

What do exfoliating acids do for your skin?

Your skin renews itself continuously, but dead skin cells sometimes linger too long, especially with stress, sun or ageing. Exfoliating acids dissolve the bonds between those cells instead of scrubbing like a scrub does. The result: skin that feels smoother and looks more even, and that absorbs caring products better. This is one of the best-researched categories in skincare, with dozens of clinical studies.

What is the difference between AHA, BHA and PHA?

Family	Examples	How it works	For whom
AHA (alpha hydroxy acids)	Lactic acid, citric acid, malic acid	Water-soluble, works on the skin's surface	Dull or uneven skin
BHA (beta hydroxy acid)	Salicylic acid	Oil-soluble, penetrates into the pore	Oily skin with blackheads. Note: we do not use BHA
PHA (polyhydroxy acids)	Gluconolactone	Larger molecule, penetrates more slowly	Sensitive skin that still wants to exfoliate

Lactic acid, citric acid and gluconolactone: the acids we use

Natural skincare and exfoliating acids may seem like two different worlds, but they are not. The acids in our formulas belong to exactly the same categories as those in the best-known exfoliants. The Apple Peeling works with AHAs from apple, lemon and red grape, around 5%, mild enough for use at home. The Rocket Eye Cream contains gluconolactone as a mild PHA. So the same active substances, just from natural sources, partly from side streams of wine and grain production, and without the loud marketing layer around them.

Which exfoliating acid suits your skin?

Rule of thumb: a mild AHA for normal to dull skin, twice a week. PHA if your skin is sensitive and you still want to exfoliate. And with every acid: use sun protection during the day, because exfoliated skin is temporarily more sensitive to the sun. If you are pregnant and unsure about acids in your routine, talk to your midwife or doctor.

Curious about the other hype ingredients and their natural counterparts? See all natural alternatives at a glance.

Frequently asked questions about exfoliating acids

What is the difference between AHA, BHA and PHA?

AHAs are water-soluble and work on the skin's surface, BHA is oil-soluble and works down into the pore, PHAs have a larger molecule and are therefore the mildest. All three exfoliate: they loosen dead skin cells for a more even complexion.

How often should you exfoliate with acids?

For most skin types, once or twice a week is enough. Your skin needs stimuli to keep renewing itself. Exfoliating more often takes over that process and can actually throw your skin off balance.

Are natural exfoliating acids milder?

Not automatically: lactic acid is lactic acid, wherever it comes from. Concentration and formulation determine how mild it is. Our Apple Peeling, at around 5% AHA, is deliberately on the mild side, suitable for use at home.

Do I need SPF when I exfoliate?

Yes, always. Exfoliating acids make your skin temporarily more sensitive to the sun. Use a sunscreen during the day: it protects your skin and prevents pigment spots from getting darker.

About the author

Written by Cathy, co-founder of Food for Skin.

I worked as a skin specialist with my own salon for 30 years. At Food for Skin, I write about ingredients and skincare, aiming to provide a nuanced and complete picture. My focus is on explaining what does and doesn't work, so you can make informed choices based on good information.