Encyclopedia · anti dandruff
Selenium sulfide
An old, inexpensive anti-dandruff active that new trials suggest works about as well as ketoconazole and has been tested across all curl types.
What it is
Selenium sulfide (selenium disulfide, SeS2) is sold as an anti-dandruff shampoo, commonly at 1%, and at higher strengths for other uses. Strengths and rules differ between countries. Several recent trials use a 0.6% SeS2 product.
How it works
It slows the turnover of scalp skin cells and is antifungal against Malassezia. A French research group also reports that it rebalances the scalp microbiome and sebum quality (Clavaud 2023, industry-affiliated review).
What the studies show
- In a 6-week randomized trial in scalp seborrheic dermatitis, 0.6% SeS2 cut scale score by 77.9% versus 69.5% for 2% ketoconazole, with no significant difference between them. SeS2 was preferred for cosmetic feel across curl types (Farris 2026).
- In a 6-week open study of 93 people of all hair types using an SeS2 shampoo twice weekly, flaking and clinical signs improved in every hair type, the microbiome rebalanced, and tolerance was good (Reygagne 2025).
- In a 4-week open study using SeS2 two to three times a week, 89.6% had at least a clear improvement and 95.6% reported less itch (Turcu 2023).
- In a cross-sectional study of 560 people using an SeS2 plus salicylic acid shampoo for about 21 days, self-rated flakes, redness, itch and greasiness all improved (p < .001); women rated results slightly lower (Wang 2025).
- As a maintenance shampoo after remission, SeS2 and zinc pyrithione showed no significant difference in time to relapse (Hasanbeyzade 2023).
Several of these studies are open-label or come from a company that markets SeS2 shampoos, so the evidence is fairly good.
How it's used in studies
Shampoo two or two to three times a week for 4-6 weeks.
Side effects and safety
Tolerance was reported as good in the trials above. We found no detailed safety data beyond that.
Bottom line
A sound, cheap alternative or rotation partner to ketoconazole and zinc pyrithione, including for textured hair. Independent head-to-head data are limited, and most trials are from industry. Discuss with a doctor.
Studies 6
Farris PK et al. Beyond Efficacy: 0.6% Selenium Disulfide Shampoo Matches 2% Ketoconazole for Seborrheic Dermatitis with Superior Cosmesis. J Drugs Dermatol. 2026
Tested: 0.6% selenium disulfide versus 2% ketoconazole shampoo
Result: Scale score fell 77.9% with selenium disulfide versus 69.5% with ketoconazole, with no significant difference between them; selenium disulfide was preferred for cosmetic feel across curl types.
Read the study ↗Reygagne PE et al. A Selenium Disulfide-Based Shampoo Is Beneficial for Dandruff Management and Rebalancing the Scalp Microbiome of Subjects of Any Hair Type. Skin Appendage Disord. 2025
Tested: selenium disulfide shampoo twice weekly (open study)
Result: Flaking and clinical signs improved in all hair types, the scalp microbiome rebalanced, and the shampoo was well tolerated.
Read the study ↗Turcu G et al. Selenium Disulfide-based shampoo applied for 4 weeks significantly improves dandruff and seborrheic dermatitis. Eur J Dermatol. 2023
Tested: selenium disulfide shampoo 2-3 times a week (open study)
Result: At least clear improvement in 89.6%; 95.6% reported less itch. Open-label and industry-linked.
Read the study ↗Wang L et al. Effectiveness and tolerance of medicated shampoo containing selenium sulfide and salicylic acid in patients with seborrheic dermatitis. J Dermatolog Treat. 2025
Tested: selenium sulfide plus salicylic acid shampoo
Result: Self-rated improvement in flakes, redness, itch and greasiness (p < .001); women rated results slightly lower.
Read the study ↗Hasanbeyzade S et al. The Effects of Zinc Pyrithione and Selenium Disulfide Shampoos on the Lesion-free Period After Treatment in Patients with Seborrheic Dermatitis. J Clin Aesthet Dermatol. 2023
Tested: zinc pyrithione versus selenium disulfide shampoo as maintenance
Result: No significant difference in time to relapse.
Read the study ↗Clavaud C et al. Selenium disulfide: a key ingredient to rebalance the scalp microbiome and sebum quality in the management of dandruff. Eur J Dermatol. 2023
Result: Industry-affiliated review proposing that selenium disulfide rebalances the scalp microbiome and sebum quality in dandruff.
Read the study ↗Related
- KetoconazoleAn antifungal shampoo ingredient that is among the best-proven treatments for dandruff and, with much weaker evidence, a possible add-on for pattern hair loss.
- Zinc pyrithioneThe most widely used anti-dandruff shampoo ingredient, proven in large trials to cut flaking, though most of those trials were run by the companies that sell it.
- CiclopiroxAn antifungal shampoo ingredient with randomized-trial support for scalp seborrheic dermatitis and a particular edge on itch, with no good evidence that it grows hair.
- DandruffDandruff is a common, chronic flaking of the scalp driven by yeast, skin oil and your skin's sensitivity, and an antifungal shampoo controls it well as long as you keep using it.
- Seborrheic dermatitisSeborrheic dermatitis is dandruff with redness and inflammation, and it is controlled rather than cured with antifungal shampoos and, for flares, short-term anti-inflammatory treatment.