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Other Ingredients

Zinc Pyrithione

Also known as: ZPT, Pyrithione zinc, Zinc omadine

The anti-dandruff and anti-acne antimicrobial — effective against Malassezia and more, with a European regulation twist.

  • By IngredientWiki Editorial Team
  • Fact-checked by IngredientWiki Editorial Team
  • Updated 2026-09-26
  • 2 min read

In short

Zinc pyrithione (ZPT) is a zinc coordination compound with broad antimicrobial and antifungal activity that has been the world's most widely used anti-dandruff active since the 1960s — the foundation of Head & Shoulders and countless OTC dandruff products. It suppresses Malassezia, the yeast driving dandruff and seborrheic dermatitis, and its activity extends to acne-associated bacteria, which is why it also appears in anti-acne washes. Its safety profile is well established at 1% OTC concentrations; notably, the EU reclassified it as a reproductive toxicant in 2022 at certain concentrations, leading to a phase-out in European rinse-off cosmetics by 2022 — a regulatory decision based on hazard classification rather than demonstrated harm at use levels.

  • World's most-used anti-dandruff active since the 1960s
  • Anti-Malassezia plus broad antimicrobial activity
  • OTC at up to 1–2%; foundation of Head & Shoulders
  • EU phased out in cosmetics (2022 CMR classification)

What is Zinc Pyrithione?

Zinc pyrithione is the molecule that made 'anti-dandruff' a household category — the active in the world's best-selling dandruff products for six decades. Its chemistry is disarmingly simple: a zinc atom coordinated to a sulfur-rich ring that microbes cannot tolerate, delivering broad antifungal and antibacterial coverage at 1% concentrations. Its track record is among the most extensive in OTC dermatology. The recent plot twist is regulatory: Europe's 2022 classification of ZPT as a category-1B reproductive toxicant phased it out of EU cosmetics, even as it remains standard in the US and elsewhere — a split that reflects different regulatory philosophies more than new evidence of harm.

Where it comes from

Natural sources

  • Synthetic zinc coordination complex of pyrithione
  • Developed in the 1950s–60s as an industrial antimicrobial and anti-dandruff agent

How it's made

Used at 0.5–2% in shampoos and washes; insoluble particles deposit on skin and release activity slowly.

What it does in products

  • Malassezia yeast suppression
  • Broad antibacterial activity
  • Sebum and flake reduction
  • Slow-release particulate delivery

Benefits

Dandruff control

strong evidence

Decades of trials confirm significant flake and itch reduction, with ZPT products among the most studied OTC dermatologic products in history.

Seborrheic dermatitis support

strong evidence

Randomized trials show symptom improvement on par with ketoconazole for facial and scalp seborrhea.

Acne support

moderate evidence

Anti-acne washes with ZPT reduce P. acnes colonization and inflammatory lesions in several trials.

Side effects & safety

Scalp dryness or irritation (uncommon)Mild and usually transient.
Allergic contact dermatitis (rare)Uncommon despite decades of mass-market use.

Safety considerations

  • OTC topical use considered low-risk; EU classification concerns occupational and aggregate exposure rather than consumer use.
  • None significant.
  • Not for: Known ZPT allergy

How it's used

In supplements

Not taken orally.

In skincare

1% in OTC dandruff shampoos (US allows up to 2% in some products); leave on 3–5 minutes before rinsing.

Regulatory status

  • FDA-approved OTC dandruff active (0.3–2%); also approved for seborrheic dermatitis.
  • INCI name on cosmetic labels: Zinc Pyrithione.
  • Previously assessed for cosmetic use; EU restriction (CMR 1B) since 2022.

Popular products containing Zinc Pyrithione

  • Head & Shoulders Classic Clean — The iconic 1% ZPT shampooHead & Shoulders · OTC drug
  • DermaZinc shampoo/soap — 2% zinc pyrithione formulationsDermaZinc · OTC drug
  • Vanicream Z-Bar — 2% ZPT cleansing barVanicream · OTC drug

Product names and brands are shown for reference and belong to their respective owners.

The EU reclassification

In 2022, zinc pyrithione was classified in the EU as a category-1B reproductive toxicant based on hazard assessment of the molecule — triggering a phase-out in European rinse-off cosmetics. The classification reflects a conservative hazard-based approach; US regulators, using risk-based assessment at OTC use levels, have maintained its status. No new human safety data drove the split.

Why it works so well

ZPT's insoluble particles deposit on the scalp, slowly releasing active pyrithione that disrupts microbial membranes and chelates metals essential to fungal growth. The slow-release profile means protection persists between washes — the practical reason ZPT products typically require fewer applications than alternatives.

Frequently asked questions

Is zinc pyrithione banned?

In EU cosmetics, effectively yes (phase-out completed 2022). In the US and most other markets, it remains a standard OTC dandruff active.

How does ZPT compare to ketoconazole?

Comparable dandruff control in head-to-head trials; ketoconazole is prescription-strength at 2%, ZPT works at 1% OTC. Both are first-line.

Can I use ZPT on my face?

Yes — 1% washes are used for facial seborrheic dermatitis, but avoid the eyes and broken skin.

The bottom line

Zinc pyrithione is a six-decade-proven anti-dandruff and seborrhea active whose EU phase-out reflects regulatory philosophy, not new evidence of consumer harm.

References

  1. Zinc pyrithione in dandruff and seborrheic dermatitis. PubMed Central. https://pubmed.ncbi.nlm.nih.gov/26054982/
  2. Zinc pyrithione: safety and efficacy review. PubMed. https://pubmed.ncbi.nlm.nih.gov/31734433/
  3. EU CMR classification of zinc pyrithione. European Chemicals Agency. https://echa.europa.eu/