Acids renew the skin more gently than physical scrubs — they dissolve the bonds between dead cells without abrading the surface. But they are not interchangeable: BHA (salicylic) is oil-soluble and works inside the pores, AHA (glycolic, lactic) renews the surface and refines texture, and PHA is the mildest, suited to sensitive skin. Below are popular acid products arranged by concern: pores, texture, pigmentation. One rule matters above all: acids are not used every day, and always alongside sun protection.
In brief, by concern: pores, blackheads, breakouts — BHA (salicylic): Anua BHA (gentle), COSRX BHA or Paula's Choice 2% BHA (stronger). Texture, dullness, fine lines — AHA (glycolic): The Ordinary Glycolic 7% or COSRX AHA. Pigmentation and post-acne marks — multi-acid formulas with a brightening effect: Some By Mi AHA-BHA-PHA. Sensitive skin — PHA, the mildest of the group. Frequency: begin two to three times a week, do not layer two acids at once, and wear sun protection during the day.
01First — which acid for which concern
BHA (salicylic) is oil-soluble and penetrates the pores — the better choice for blackheads, congested pores and oiliness (particularly on the nose and chin). AHA (glycolic, lactic) is water-soluble and works on the surface — for dullness, uneven texture and fine lines (more noticeable on the cheeks and forehead). PHA has larger, gentler molecules that renew and hydrate at once, and suits sensitive skin. When several concerns overlap, a multi-acid formula can help. For an acid to work it needs a pH of roughly 3–4, which reputable brands calibrate carefully.
02Pores, blackheads, breakouts (BHA)
Anua BHA 2% Gentle Exfoliating (mild). A toner with 2% BHA, plus ceramides, hyaluronic acid and panthenol to support the barrier, and tea tree extract to calm — it exfoliates gently without leaving the skin tight. A good introduction to acids for oily, combination and blemish-prone skin, newcomers included. From our editorial team's own experience: it does not irritate the skin, feels gentle, and cleans well.
COSRX BHA Blackhead Power Liquid (moderate). A serum-like texture with salicylic acid and niacinamide — it clears the pores and helps with blackheads, without feeling as heavy as some alternatives. Suited to oily and blemish-prone skin. It contains niacinamide, which is convenient, though some prefer not to layer it with vitamin C in a single step.
Paula's Choice 2% BHA Liquid (strong, a dermatologist favourite). One of the most widely recommended products: 2% salicylic acid at a well-judged pH cleans the pores deeply and reduces blackheads, with visible results in four to six weeks. The texture is slightly oily (which may not suit oily skin by feel). A 1% BHA version is available for sensitive skin.
03Texture, dullness, fine lines (AHA)
The Ordinary Glycolic Acid 7% (budget AHA). A toner with 7% glycolic acid at a working pH — it smooths texture, restores radiance and evens out tone. Noticeably cheaper than comparable products. Suited to normal, combination and oily skin. Note that 7% is not a starting concentration: begin twice a week in the evening and watch how the skin responds.
COSRX AHA/BHA Clarifying Treatment Toner (mild, dual-action). It combines AHA and BHA at a low concentration — gently renewing the surface while lightly clearing the pores. A good option for those dealing with both texture and pores, and for easing into acids on combination skin.
04Pigmentation and post-acne marks
Some By Mi AHA-BHA-PHA 30 Days Miracle Toner (multi-acid). It brings together three types of acid at a moderate concentration, along with tea tree — renewing the surface, clearing the pores and helping to even out tone and post-acne marks without over-drying. Suited to oily and blemish-prone skin with uneven tone. As with any multi-acid product, sensitive skin should introduce it gradually.
The Ordinary AHA 30% + BHA 2% Peeling Solution (strong, once a week). A potent peeling mask for weekly use: it visibly brightens and renews, and helps with dullness and post-acne marks. Apply for no more than 10 minutes, no more than once a week, and do not combine it with other acids on the same days. Not for sensitive skin, and not for beginners.
A note for sensitive skin: if acids have caused stinging and flaking before, begin with PHA — the mildest group, which renews and hydrates without irritation. Many multi-acid toners (Some By Mi among them) include PHA as a softening component.
Azelaic acid deserves a separate mention: despite the name, it does not work through exfoliation but instead suppresses pigmentation, targets acne-causing bacteria and calms the inflammation of rosacea. That makes it a sound choice for problem-prone and reactive skin. We cover it and specific products in a separate review of azelaic acid.
- Using acids every day from the very start. Begin two to three times a week (strong peels once a week), and increase the frequency only if the skin tolerates it well.
- Layering two acids, or an acid and retinol, on the same evening. This overloads the skin; alternate them on different days instead.
- Skipping sun protection. Acids increase sensitivity to sunlight — without it, they deepen pigmentation rather than lifting it.
- Continuing to exfoliate on a damaged barrier. If stinging and flaking appear, acids should be paused and the barrier restored.
- Choosing a product that lists an acid but has no working pH. Above pH 5 the acid barely works; favour brands that state their pH.
05What to buy for your concern
Pores / blackheads / breakouts (BHA)
Texture / dullness (AHA)
Pigmentation / post-acne marks
These are affiliate links. Buying through them does not change the price for you, but it supports the project. The selection is based on the concern and type of acid, not on the size of the commission.
06Common questions
What is the difference between AHA, BHA and PHA?
AHA (glycolic, lactic) is water-soluble and renews the surface — for texture and dullness. BHA (salicylic) is oil-soluble and reaches into the pores — for blackheads and breakouts. PHA has larger, gentler molecules, suited to sensitive skin. Different concerns call for different acids.
How often can acids be used?
Mild toners (Anua, COSRX AHA/BHA) two to three times a week, building up gradually. Strong peels (The Ordinary 30/2) no more than once a week. Daily use tends to harm the barrier — more is not better.
Can acids be combined with retinol or vitamin C?
Not on the same evening. It is better to alternate an acid and retinol on different days. Keep vitamin C and acids apart in time as well. Otherwise the risk of irritation and barrier damage is high.
Information on acids, concentrations and pH is drawn from openly available and peer-reviewed material:
This material is educational and does not replace a consultation with a dermatologist. Introduce acids gradually, with a patch test and consistent sun protection. If the barrier is damaged or irritation is strong, take a break.