Science
Mechanism of Action
It disrupts microbial cell membrane integrity and essential metabolic functions by blocking proton pumps and increasing intracellular zinc, leading to cellular stress. Its antifungal action also targets critical iron-sulfur proteins, inhibiting fungal energy production.
Research
Clinical Evidence
High confidence1%
Key findings
- 01 A 1% shampoo significantly reduced dandruff over multiple washes compared to placebo.
- 02 2% in rinse-off products effectively treats seborrheic dermatitis and fungal conditions.
- 03 0.25-0.5% active used in leave-on hair and skin products.
Transparency
Dusting Analysis
Due to its classification as a presumed human carcinogen, mutagen, or reproductive toxicant (CMR 1B) by ECHA, it is banned in cosmetics in Europe, leading to ineffective use or avoidance.
The Formula
Formulation
Stability
It has very low solubility in water (5-20 ppm) and is insoluble in oil, typically requiring high-speed blending for dispersion. It is unstable in light, oxidizers, acids, and bases, especially at higher temperatures.
Conflicts
- EDTA (and other chelating agents)
- Cationic surfactants
- Non-ionic surfactants
- Heavy metals
- Oxidants (e.g., peroxides)
Safety
Safety Profile
The CIR Expert Panel did not review Zinc Pyrithione due to its chemical distinction from other zinc salts. Despite FDA approval for OTC use in the US, the EU has banned it in cosmetics since March 2022 due to its classification as a CMR 1B substance.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Due to its classification as a presumed human carcinogen, mutagen, or reproductive toxicant (CMR 1B) and subsequent ban in the EU, this ingredient is not recommended for cosmetic use.
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