Common Name(s): Hydroxy methylphenylpyridinone,hydroxy methylphenylpyridinone,anti-dandruff antifungal,malassezia-targeting iron chelator
CAS Number: N/a
DESCRIPTION
What It Does: Inhibits malassezia scalp fungal growth through iron chelation — depriving the dandruff-causing yeast of iron required for electron transport chain activity and lipase enzyme function that generates the irritant oleic acid responsible for flaking.
Why It's Used: Iron chelation is the most selective anti-malassezia mechanism — malassezia is a strict iron-requiring organism with limited iron acquisition alternatives; iron deprivation selectively kills malassezia while sparing commensal bacteria that have more versatile iron acquisition systems.
How It Works: Hydroxypyridinethione forms a stable neutral fe³⁺ complex (log stability constant ~30) → malassezia iron deprivation → inhibited electron transport (iron-sulfur cluster enzymes) → reduced lipase expression → decreased oleic acid production from sebum triglycerides → reduced scalp barrier disruption → reduced dandruff flaking.
Typically Found In: Anti-dandruff,scalp care,antifungal
TECHNICAL DETAILS
Primary Category: Active ingredient – cosmetic active
Secondary Functions: Skin conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.01%–1%
SOURCING & ETHICS
Vegan Status: Conditional - supplier confirmation required
Halal Status: Unverified - supplier confirmation required
Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier. [audit 2026-07-29 rev2: the record's own source_notes does not assert a non-animal origin, or instructs the reader to verify with the supplier; "yes" asserts knowledge the record does not hold. determination requires shariah-panel sign-off.]
SKIN COMPATIBILITY
Irritancy Rating: 1/5 – very low
Comedogenicity Rating: 0/5 – non-comedogenic
Sensitivity Concerns: Well-tolerated by most skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Good safety profile at recommended concentrations. ewg score: 1–2.
Works Well With: Standard skincare actives
Avoid Combining With: No known significant incompatibilities
SCIENTIFIC NOTE
Pyrithione family: zinc pyrithione (zpt) is the reference standard; octopirox (pirocton olamine) provides broader antifungal at similar concentrations; hydroxy methylphenylpyridinone variants provide the iron chelation mechanism with different substituents affecting scalp compatibility.
Last Verified: 2026-03-22
Primary Sources: Cosing database,hydroxy methylphenylpyridinone antifungal anti-dandruff review