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How much salicylic acid (BHA) do you need? 0.5%+

The effective salicylic acid (BHA) percentage, by the vehicle-controlled trials, starts at 0.5% (by the pad maker’s own reading of its unpublished placebo studies); no published dose comparison sets a ceiling.

Written by Maya Faour, founder and sole writer; not a dermatologistHow we work →Published Reviewed

Dose line for Salicylic acid (BHA): the trials worked from 0.5% with no measured ceiling; ticks at 0.5%, 2% where the named trials worked; the highest dose in the literature is another use, not drawn: 60% on plantar warts, an ointment used with monochloroacetic acid crystals; US monograph at 0.5 to 2%; catalogue labels at 2%. Linear scale.0.5%, Zander 19922%, Zander 19920.5%2%Zander 1992Zander 1992The Ordinary AHA 30% + BHA 2% Peeling Solution: 2%The Ordinary Salicylic Acid 2% Solution: 2%Paula's Choice Skin Perfecting 2% BHA Liquid Exfoliant: 2%US monograph 0.5 to 2%0%2.3%

0.5%, Zander 1992.

Floor 0.5%, the pad maker's own reading: A review of four clinical studies and a comedolytic assay attests to the efficacy and safety of 0.5% and 2% solutions of salicylic acid for the treatment of acne vulgaris. (Zander 1992: three placebo-controlled pad studies at 0.5% and 2%, unpublished, summarised by the maker; the US 0.5 to 2% acne monograph, 21 CFR 333.310, rests on them).

The rose band is where the vehicle-controlled trials worked (by the pad maker’s own reading of its unpublished placebo studies), open to the right because no dose comparison sets a ceiling; each tick is a concentration a named trial used, with its author and year; the highest dose in the literature is another use, 60% on plantar warts, an ointment used with monochloroacetic acid crystals (Steele 1988), so this line does not draw it; the dashed line is the regulator’s number (US monograph, 0.5 to 2%); the bottles above the line are the products in our catalogue that declare a percentage on the name, hollow where it falls outside the trials’ range. The scale is linear (0 to 2.3%).

What salicylic acid (BHA) percentage is effective?

Floor 0.5%, the pad maker's own reading: A review of four clinical studies and a comedolytic assay attests to the efficacy and safety of 0.5% and 2% solutions of salicylic acid for the treatment of acne vulgaris.

0.5%+

The trials, and what they used
  • (Zander 1992: three placebo-controlled pad studies at 0.5% and 2%, unpublished, summarised by the maker; the US 0.5 to 2% acne monograph, 21 CFR 333.310, rests on them).
  • No independent vehicle-controlled trial of a leave-on salicylic acid at a stated percentage is published.
  • What is published pins 2% against approved actives: a 2% salicylic acid hydrogel matched adapalene gel on lesion clearance in 500 patients over 12 weeks (Ye 2024), a 2% cream with 0.5% chloroxylenol matched 5% benzoyl peroxide in 37 patients over 12 weeks, double-blind (Boutli 2003), and a 2% cleanser reduced comedones where a 10% benzoyl peroxide wash did not in a 30-patient crossover (Shalita 1989).
  • No dose comparison found.
  • EU Annex III/98 (Regulation 2022/1181, after SCCS/1601/18) allows 2% in leave-on products and 3% in rinse-off hair products; a regulatory ceiling, not an effect ceiling.

Is 2% salicylic acid (BHA) too much?

Nobody has measured it: no published dose comparison sets a ceiling for salicylic acid (BHA), so 2% is above the 0.5% floor the trials used, not above a measured maximum, and the trials say nothing about whether more does more. The highest dose in the literature is another use: 60% on plantar warts, an ointment used with monochloroacetic acid crystals (Steele 1988).

Treatments were well tolerated.

The highest dose in the literature, in the paper’s words
  • Treatments were well tolerated.

No published dose comparison sets a ceiling for salicylic acid (bha). A declared percentage above 0.5% is above the trials' floor, not above a measured maximum: the trials say from 0.5% it works, and say nothing about whether more does more.

What does the salicylic acid (BHA) percentage on a label tell you?

A name that states a percentage ("Salicylic acid (BHA) 0.5%") is the only amount a cosmetic label ever declares, so it is the one number that can be read against the trials: at or above the 0.5% floor, or below it.

A name without a percentage leaves the position. The rules make a brand list ingredients in descending order of amount down to 1%, and in any order below it, so salicylic acid (bha) above the 1% line is at least 1% and salicylic acid (bha) below it can be any trace the brand likes. The floor the trials worked from is 0.5%, and a position alone cannot tell you whether a label reaches it.

The salicylic acid (BHA) percentages in our catalogue

The 9 products in our catalogue that carry salicylic acid (BHA): the number is the percentage the name declares, or the position on the label where it declares none.

3 labels declare a percentage on the name, read against the trials:

6 labels carry it without a number, so the position is all there is:

Read on

Other actives with a dose the trials pinned:

The range column was researched and verified in September 2026 (this row last changed 22 September 2026). The number is the trials' and the reasoning is the knowledge base's; neither is advice about your skin. How we score.