AHA vs BHA: what is the difference and how to exfoliate without damaging your skin

Rough texture, blackheads, dull complexion: chemical exfoliation with acids is gentler than a grainy scrub, provided it is used well. This guide covers the points addressed by Nivea, Paula’s Choice, NeoStrata, Payot and Endro, adapted to life in Morocco (hammam, sun, climate).

What are AHAs and BHAs?

• AHA (alpha hydroxy acids): glycolic, lactic, mandelic and citric acids. Water-soluble, they work on the surface of the skin.
• BHA (beta hydroxy acid): salicylic acid, oil-soluble, which penetrates the pores.
• PHA (polyhydroxy acids): gluconolactone, lactobionic acid, gentler, suited to sensitive skin.

AHA vs BHA: what are the differences?

AHAs help remove dead cells and revive radiance. BHA helps unclog pores and reduce the look of blackheads. AHAs suit dull or dry skin; BHA suits combination to oily skin. Together, they refine skin texture.

• Area of action: AHA on the surface, BHA in the pores.
• Solubility: AHA in water, BHA in oil (sebum).
• Goal: AHA for radiance, texture and an even tone; BHA for blackheads, pores and excess sebum.
• Skin type: AHA for dull, dry or mature skin; BHA for combination to oily skin.
• Tolerance: BHA is often better tolerated by oily skin; AHAs, especially glycolic acid, can tingle more.

Detailed comparison: NIVEA and Paula’s Choice.

The benefits

• Smoother, more luminous skin.
• Less visible pores and blackheads.
• Better absorption of the products that follow.
• A more even-looking complexion.

Which percentages to choose?

To start: AHA around 5% and BHA at 1 to 2% (our AHA BHA exfoliating toner, AHA 5% + BHA 2%). More concentrated serums (our AHA BHA serum, AHA 10% + BHA 2%, or 30% peels) are for skin that is used to acids. A suitable pH matters as much as the percentage.

How often to exfoliate?

1. Weeks 1 and 2: once a week, in the evening.
2. Weeks 3 and 4: twice a week.
3. Then: two to three evenings a week at most.

How to apply an acid exfoliant

1. Do a patch test in the crook of the elbow.
2. Cleanse and dry the face completely.
3. Apply a thin layer, avoiding the eye contour.
4. Follow the time indicated on the product.
5. Then hydrate with a hyaluronic acid serum and a cream.

AHA, BHA and sun protection

Exfoliating acids make the skin more sensitive to the sun. The next morning, SPF 50, especially in the Moroccan climate.

Is BHA dangerous?

Salicylic acid is regulated: in the European Union, its concentration is capped at 2% in leave-on facial cosmetics. Used correctly, it is widely used. Avoid it during pregnancy if your doctor advises against it, and seek advice if you are allergic to aspirin.

Can the two be used together? With which actives?

• AHA + BHA: yes, often in the same formula.
• Retinol: not on the same evening (retinol guide).
• Pure vitamin C: keep separate (morning / evening).
• Niacinamide: an excellent complement (niacinamide guide).

Sensitive skin, hammam and scrubs

Reactive skin: once every ten days, or PHAs. No acids right after the hammam or after a scrub: the skin is already sensitised by heat and friction. Wait at least 48 hours.

How to tell if you are over-exfoliating?

Skin that feels tight, has a “varnished” shine, peels, turns red, or sudden small breakouts. Stop acids for one to two weeks, hydrate, then resume less often.

Brand comparison

• Paula’s Choice: Skin Perfecting 2% BHA Liquid Exfoliant, the BHA benchmark.
• The Ordinary: AHA 30% + BHA 2% Peeling Solution, a powerful peel for limited use.
• COSRX, Some By Mi: K-beauty AHA/BHA toners at gentle strengths.
• NeoStrata: a dermatological range with AHAs and PHAs.
• Cosmogenesis Labs: AHA 5% + BHA 2% toner to start, AHA 10% + BHA 2% serum for skin used to acids.

For the complete routine, see the refined pores routine and our oily skin routine guide.

Putting it into practice

New to acids? The AHA BHA exfoliating toner (AHA 5% + BHA 2%) is applied with a cotton pad after cleansing, two to three evenings a week. Is your skin already used to them? The AHA BHA serum (AHA 10% + BHA 2%) targets texture and pores more intensely. Each product page details the formula, frequency and combinations.

Sources and further reading

• NIVEA: AHA vs BHA
• Paula’s Choice: AHA vs BHA
• NeoStrata: the art of exfoliation

Informational content that does not replace the advice of a healthcare professional. If in doubt, for reactive skin, during pregnancy or for a dark spot that changes, consult a dermatologist.

Frequently asked questions

What is the difference between AHA and BHA?

AHAs work on the surface, BHA penetrates the pores. They complement each other.

How often should exfoliating acids be used?

Once a week at first, then two to three evenings a week at most.

Is SPF needed with AHA and BHA?

Yes, SPF 50 every morning.

Can AHA/BHA be used with retinol?

Not on the same evening. Alternate.

Can you exfoliate after the hammam?

Best avoided: wait at least 48 hours.

Are AHA and BHA suitable for sensitive skin?

With caution: start infrequently, patch test, or choose PHAs.