Ph
Phosphoric Acid
Phosphoric Acid
A strong acid used in tiny amounts to adjust a product’s acidity (pH).
What it does
It’s there to adjust and steady the product’s pH, not to change your skin.
The EU’s ingredient database lists it as a pH adjuster (sets how acidic the product is).European Commission, CosIng (© European Union, CC BY 4.0) · uses put in plain words by Drop ↗
The evidence, graded
expert consensusUS safety reviewers (2021) assessed phosphoric acid and 30 of its salts, used among other jobs to adjust and steady pH. Phosphoric acid was in 489 products, mostly rinse-off. At 2.5% it irritated skin, but that solution was very acidic (pH 2.1). From 17.5% up it was corrosive, meaning it damaged skin, though one test at 19% found no irritation. It didn’t cause allergy in people. They judged it safe as used, in products made not to irritate.Johnson 2021 · International Journal of Toxicology ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
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