Hypochlorous acid: what it can and can’t do
Hypochlorous acid sprays are all over social media. Here’s what’s in them, and whether they live up to the hype.
The short version
- Hypochlorous acid is very dilute bleach chemistry.
- There’s no rigorous evidence it treats acne, rosacea or barrier damage.
- It probably won’t harm healthy skin, but it can dry out skin that’s already struggling.
What it is
In a word: bleach. Hypochlorous acid is the same chemistry as household bleach, just very dilute.
Does it do what social media says?
In another word: no. The claims are overblown. There are no rigorous human studies showing it can treat acne or rosacea, improve the skin barrier, help wounds heal or prevent skin cancer. Those are all therapeutic claims, not cosmetic ones.
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Eczema, acne and the microbiome
Dilute bleach baths have long been used for eczema, to reduce bacteria (especially staph) on the skin. But systematic reviews show the results are variable at best, and ineffective at worst. It makes some sense in eczema, where certain bacteria overgrow, but the evidence doesn’t support it as a main treatment.
Acne is different. Cutibacterium acnes is a normal skin organism that lives in pores. It contributes to acne by triggering inflammation and the build-up of skin cells that plug pores, not by overgrowing or infecting. So using bleach to reduce bacteria makes no sense when there’s no overgrowth to begin with.
‘Disinfecting’ skin is an outdated idea. We now know a diverse, balanced skin microbiome matters in inflammatory skin conditions, which is why supporting the skin barrier is so important.
It’s also an oxidising agent, so in theory it could break down some retinoids if you use them at the same time.
Can it harm skin?
Probably not. But if you have a skin condition, your barrier is likely already compromised, and adding dilute bleach may cause dryness and irritation.
Our verdict
If your skin is healthy, leave the bleach for the toilet and off your face. If you have a skin condition, get evidence-based advice instead.
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- Bakaa L, Pernica JM, Couban RJ, et al. Bleach baths for atopic dermatitis: a systematic review and meta-analysis. Ann Allergy Asthma Immunol. 2022;128(6):660-8.
- Ong PY, Boguniewicz J, Chu DK. Skin antiseptics for atopic dermatitis: dissecting facts from fiction. J Allergy Clin Immunol Pract. 2023;11(5):1385-90.
- Del Rosso JQ, Bhatia N. Status report on topical hypochlorous acid. J Clin Aesthet Dermatol. 2018;11(11):36-9.
This article is general information only. It isn’t a substitute for personal medical advice, so speak with a health professional about your own skin.
