What are they?

BHA (or beta hydroxy acid) and AHA (or alpha hydroxy acid) are the two most common types of chemical exfoliators. In opposite to mechanical scrubs, that come in a grainy-creamy texture, chemical peels are usually in liquid or sometimes in simple cream form. They remove dead skin cells through “ungluing” the sticky bonds that are holding the dead skins onto the surface of your skin. You will not see your dead skin shedding but after a short while your skin will become much softer, brighter and younger.


Difference between BHA and AHA

AHA (alpha hydroxy acid) exfoliators are water soluble and derived naturally from sugar beets/canes (glycolic acid), from sour milk (lactic acid) or from fruits (malic acid from apples & pears, citric acid from lemons & oranges, tartaric acid from grapes) and perfect to those with drier & flakier skin. The recommended % of AHA is 7-10%. Anything higher than 10% in concentration might be too irritating to your skin and should be only used in professional treatments by your beautician.

BHA (beta hydroxy acid) exfoliators are oil soluble salicylic acid based peels and recommended for more oily type of skin.  The recommended concentration is between 3-5% for at-home products – perfectly enough if you want a safe but long-term results.

Here a small comparison table to understand the difference and the benefits of AHA and BHA:


AHA (alpha hydroxy acid)BHA (beta hydroxy acid)
for drier / flakier skinfor oily, combination skin
removes dead cells from the surface of the skinremoves dead cells from the surface of the skin and from the pores
it has a moisturizing effectit can have a drying effect (above 5% concentration)
helps build collagen and renew the skinhas antibacterial and anti-inflammatory properties
perfect to reduce fine lines, wrinkles and even out skin textureperfect to clean pores (blackheads), fight against acne and heal inflammation

Which one should you use?

If you have oily, acne prone skin or struggle with blackheads, you should opt for BHA type of exfoliators.


COSRX BHA Blackhead Power Liquid

COSRX Low pH BHA Overnight Mask


If you have drier skin and/or struggle with fine lines and skin texture (whiteheads, bumps, flaky skin), you should definitely opt for an AHA type of exfoliator:

COSRX AHA 7 Whitehead Power Liquid

COSRX AHA/BHA Clarifying Treatment Toner


How to use chemical exfoliators?

Both AHA and BHA products work best if you

  • take it slow: use it two-three times a week before you jump into a daily routine
  • use it in the evening
  • apply it on cleansed skin
  • wait 20-30 min before you apply any other product
  • use sun screen for the day

The waiting time is essential since chemical exfoliators work best in low pH environment (what you usually achieve with cleansing) and adding a higher pH cream or other treatment product too early would basically cancel the effect of the chemical exfoliators. After roughly 30 min you skin naturally bounces back to its normal pH level and you can apply without any problem your moisturizer.

Wearing sun screen during the day is another essential part since chemical exfoliators make your skin prone to UV damage. Without protecting your skin, you can basically undo all the good you have achieved with your BHA/AHA application.

For deeper exfoliators, you can use a combination of BHA & AHA products. However, we would only recommend it for those who are already familiar with the effects & application!


Risks of chemical exfoliation

If you have very sensitive skin or react badly to acidic type of exfoliators, better you test them first if you can or you avoid them completely. If you experience skin thickening, redness, itchiness after 2-3 application still, it means you “over-exfoliated” your skin and you should rather skip exfoliation totally for a while.


Founder of The SKIN Stories and the indie-beauty shop, The Curated SKIN.

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