At a glance
| Chemical family | Zinc coordination compound — antifungal and antimicrobial biocide |
| CAS number | 13463-41-7 |
| Classification | Not classified as a carcinogen by IARC. EU CLP Repr. 1B (H360D — may damage the unborn child), Acute Tox. 3, Aquatic Acute 1 / Chronic 1. CMR classification triggered EU cosmetics ban |
| Where you encounter it | Anti-dandruff shampoos (most brands worldwide); antimicrobial textile treatments; antifouling paints; preserved plastics and coatings |
| Sleep micro-environment relevance | Transfers from hair/scalp to pillowcases. Found in antimicrobial-treated textiles. EU cosmetics ban (2022) based on reproductive toxicity, though consumer dermal exposure from rinse-off shampoo is low |
Regulatory & certification status
| European Union | Banned in cosmetics from March 2022 (Regulation 2021/1902) after CMR reclassification as Repr. 1B (H360D). Still authorised under BPR for textile preservation (product type 9). EU CLP: Repr. 1B, Acute Tox. 3, Aquatic Acute 1. Regulatory |
| United States | FDA permits zinc pyrithione in anti-dandruff products (OTC monograph active ingredient). No CMR restriction. EPA registered as an antimicrobial. Regulatory |
| Canada | Permitted in anti-dandruff products. Health Canada Natural and Non-prescription Health Products Directorate monograph. Regulatory |
| International | Not IARC classified. Remains in anti-dandruff products in most markets outside the EU. OEKO-TEX does not list a specific limit (biocidal function is covered under general antimicrobial testing). Regulatory |
What it is
Zinc pyrithione is a coordination complex of zinc with pyrithione (2-mercaptopyridine N-oxide). It has potent antifungal and antibacterial properties and has been the dominant anti-dandruff active ingredient globally since the 1960s. It works by disrupting fungal membrane transport and inhibiting the growth of Malassezia yeasts on the scalp. IARC has not evaluated zinc pyrithione for carcinogenicity. In 2021, the EU reclassified zinc pyrithione as Repr. 1B (H360D) under CLP, based on developmental toxicity studies in rats. This CMR classification triggered an automatic ban in EU cosmetics from March 2022 under the Cosmetics Regulation 1223/2009. Outside the EU, zinc pyrithione remains widely available in anti-dandruff products.
Where it shows up in bedding
Zinc pyrithione enters the bedroom through two pathways. First, residue from anti-dandruff shampoo on hair and scalp transfers to pillowcases during sleep — this is a small amount that decreases with rinsing. Second, zinc pyrithione is used as a biocidal treatment in some textiles (antimicrobial, anti-odour, or mildew-resistant fabrics), where it is embedded in or applied to the fibre. The EU Biocidal Products Regulation (BPR) authorises zinc pyrithione for product type 9 (fibre, leather, rubber and polymerised materials preservative). At the trace levels present in either pathway, zinc pyrithione is not a significant health concern for adults. The EU cosmetics ban was driven by precautionary developmental toxicity classification, not by documented harm at consumer exposure levels.
Citations
- EU Commission Regulation 2021/1902 amending Annex V to Regulation 1223/2009 (zinc pyrithione cosmetics restriction). Source Regulatory
- ECHA. Zinc pyrithione — Substance Information. Source Regulatory
- Schwartz, J.R. et al. (2011). Zinc Pyrithione: A Topical Antimicrobial With Complex Pharmaceutics. Journal of Drugs in Dermatology, 10(2): 142-148. Source Peer-reviewed
Frequently asked questions
Why did the EU ban zinc pyrithione in shampoo?
The EU did not ban zinc pyrithione because of documented harm to consumers. In 2021, the EU reclassified zinc pyrithione as Repr. 1B (may damage the unborn child) based on developmental toxicity studies in rats. Under EU cosmetics law, CMR-classified substances are automatically prohibited from cosmetics unless a specific exemption is granted. The reclassification was precautionary — the actual consumer exposure from rinse-off shampoo is very low.
Is zinc pyrithione on pillowcases harmful?
At the trace amounts that transfer from hair to pillowcases during sleep, zinc pyrithione is not a health concern for adults or children. The reproductive toxicity that triggered the EU cosmetics ban was observed in animal studies at doses far exceeding what a person would absorb from a pillowcase. If you have concerns, washing pillowcases regularly reduces any residue.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-07. If you find a factual error, contact us.