Pyrithione Zinc
Zinc Pyrithione · ZPT
What it is
An antimicrobial and antifungal active ingredient used at 1% in OTC anti-dandruff shampoos in the US. Controls Malassezia yeast associated with dandruff.
In this product: Anti-dandruff active, antimicrobial and antifungal.
Dose & route, what actually matters
Scalp dermal absorption during rinse-off contact. Brief exposure, but ECHA classified ZPT as Reproductive Toxicity Category 1B based on reproductive and developmental data, meaning even rinse-off use was deemed too high-risk.
EUROPEAN UNION
BANNED. European Commission Regulation (EU) 2021/1902 added ZPT to Annex II of EU Cosmetics Regulation 1223/2009 (prohibited substances list). In force March 1, 2022. Simultaneously removed from Annex V (permitted preservatives) and Annex III (restricted substances). An SCCS safety opinion found the shampoo safe, but EU law bans CMR substances unless no alternative exists; alternatives do exist for dandruff control.
UNITED STATES
Permitted as an OTC drug active ingredient at 0.3–2% for anti-dandruff shampoos under FDA OTC monograph (21 CFR 358.710). Head & Shoulders sold at 1% ZPT with no restriction.
The evidence
ECHA Risk Assessment Committee (RAC) classified Zinc Pyrithione as Reproductive Toxicity Category 1B ('presumed to have the potential to impair fertility or cause developmental toxicity in humans') in 2018, triggering the EU cosmetics ban.
regulatory · 2018 · source
Regulation (EU) 2021/1902 added ZPT to Annex II (prohibited substances); ban came into force March 1, 2022. The same product remains legally sold as an OTC drug in the US.
regulatory · 2022 · source
California Prop 65: Not listed.
How to avoid it
Look for anti-dandruff shampoos using selenium sulfide, coal tar, salicylic acid, or ketoconazole instead of zinc pyrithione. Many clean-label brands avoid ZPT entirely.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.