PYRITHIONE ZINC

📋 Quick facts

Description: PYRITHIONE ZINC — PYRITHIONE ZINC. Formula: C10H8N2O2S2Zn. MW: 317.7. IUPAC: zinc bis(1-oxidopyridin-1-ium-2-thiolate).

Quick Facts:

• Category: other
• Also Known As: Zinc pyrithione
• Regulatory Note: Restricted in the US

Proven Benefits At A Glance:

• Pyrithione zinc is an antifungal and antibacterial ingredient used in dandruff and seborrheic dermatitis shampoos
• A 1% pyrithione zinc shampoo showed modest but sustained improvements in hair count over 26 weeks when used daily
• The hair growth benefit of pyrithione zinc was about half that of minoxidil (a well-established hair loss treatment)
• Studies found no evidence that pyrithione zinc’s dandruff-fighting benefits weaken over time with continued use
• Combining pyrithione zinc shampoo with minoxidil showed no additional benefit compared to minoxidil alone

⚗️ Chemical Overview

Zinc pyrithione is a fine beige granules. (NTP, 1992) Pyrithione Zinc is a coordination complex of the zinc ion and pyrithione, a derivative of the naturally occurring antibiotic aspergillic acid with antimicrobial, antifungal and anti-seborrheic effects. Although the exact mechanism of action remains to be fully elucidated, pyrithione zinc appears to interfere with the membrane transport of ions and metabolites, ultimately leading to a loss of metabolic control. In addition, this agent causes an influx of copper, leading to a reduction in the activity of iron-sulphur proteins resulting in growth inhibition. Zinc pyrithione is a chemical compound of zinc. It is used as an antifungal and antibacterial agent. Zinc is a metallic element with the atomic number 30. It is found in nature most often as the mineral sphalerite. Though excess zinc in harmful, in smaller amounts it is an essential element for life, as it is a cofactor for over 300 enzymes and is found in just as many transcription factors. (L48, L49, L76)

Source(s): NCI Thesaurus (NCIt), Toxin and Toxin Target Database (T3DB), CAMEO Chemicals, via PubChem

📊 Comedogenicity

🛡️ Safety rating

Safety tier is a starting heuristic from regulatory status and comedogenic rating, not a dermatological verdict — see our Terms for the full disclaimer. Research confidence reflects how many real cited studies back this ingredient, not the strength of their findings.

🌍 Regulatory Status

💧 Skin Type Compatibility

⚠️ Don’t Combine With

📚 Research & Evidence

🔬 The Science

Pyrithione zinc is an ingredient that works by fighting fungi and bacteria on the scalp. The research on this ingredient covers two main areas: dandruff control and hair growth. For dandruff and seborrheic dermatitis (a chronic inflammatory scalp condition): #1: Pyrithione zinc shampoos are effective at reducing scalp flaking, which is the primary symptom of these conditions (Int J Dermatol, 2009). Interestingly, while many dermatologists believed that people’s bodies would adapt to pyrithione zinc over time—a phenomenon called tachyphylaxis—clinical studies found no evidence this actually happens within 48 weeks of regular use (Int J Dermatol, 2009). This means the ingredient continued to work consistently even with long-term daily application.

For hair growth: #2: A 1% pyrithione zinc shampoo produced a modest but measurable increase in total hair count when used daily over 26 weeks in men with male pattern baldness (Br J Dermatol, 2003). The improvement was “modest and sustained,” meaning it stayed consistent throughout the study period. However, #3: the hair count increase from pyrithione zinc was notably smaller—roughly half—compared to minoxidil, which is an FDA-approved hair loss treatment (Br J Dermatol, 2003). A small increase in hair thickness was observed with minoxidil-containing treatments, though this wasn’t specifically measured for pyrithione zinc alone. #4: When researchers tested using pyrithione zinc shampoo together with minoxidil, there was no additional benefit beyond what minoxidil alone provided (Br J Dermatol, 2003).

The sources are limited to these specific findings and don’t address other potential uses or benefits of pyrithione zinc beyond dandruff control and modest hair growth effects.

📄 Related Research

Matched by search — not necessarily verified support for every statement above.

• Berger RS et al. (2003). The effects of minoxidil, 1% pyrithione zinc and a combination of both on hair density: a randomized controlled trial. Br J Dermatol.
• Brandrup F et al. (1985). Zinc pyrithione (Zinc Omadine) allergy. Contact Dermatitis.
• Schwartz JR et al. (2009). Does tachyphylaxis occur in long-term management of scalp seborrheic dermatitis with pyrithione zinc-based treatments?. Int J Dermatol.

🧴 Products Containing PYRITHIONE ZINC

• head & shoulders coconut shampoo
• head and shoulders Head and Shoulders Refreshing Menthol Anti-Dandruff Shampoo For Men
• head & shoulders coconut conditioner
• Head & Shoulders Tea Tree Oil Shampoo