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Selenium Sulfide in skincare
Effective anti-dandruff and anti-seborrheic active; FDA-approved OTC at 1%; can discolor treated hair; rinse thoroughly.
Found in anti-dandruff shampoos (rinse-off, AM and PM appropriate). Rinse thoroughly after use. Do not allow prolonged skin contact. Prescription-strength (2.5%) requires dermatologist supervision. OTC 1% is available for regular dandruff control. Discolors bleached, tinted, or gray hair. Leave on briefly and rinse thoroughly.
What it is
Selenium Sulfide (SeS₂) is a potent antifungal and cytostatic agent used for treating dandruff, seborrheic dermatitis, and tinea versicolor (a Malassezia-related skin discoloration). Mechanism: reduces mitotic activity (cell turnover) of the scalp epidermis and directly inhibits Malassezia yeast growth. FDA OTC monograph: approved at 1% in shampoos for dandruff control. Prescription: 2.5% formulation (Selsun) for seborrheic dermatitis and tinea versicolor. Requires dermatologist supervision. Safety notes: (1) Selenium is toxic in excess. Do not use on broken skin, avoid contact with eyes (causes irritation), and rinse thoroughly; (2) Discolors chemically treated, bleached, or gray hair. Minimize contact time; (3) Some systemic absorption occurs. Avoid daily use and extended leave-on contact; (4) IARC classifies selenium compounds as Group 3 (not classifiable as to carcinogenicity) for occupational exposure; no carcinogenicity concern at topical OTC doses. Well-established efficacy for severe dandruff/seborrheic dermatitis.
The facts
| Category | Anti-dandruff / Antifungal Active |
| Typical use | Morning and evening |
| Concentration YARAI treats as a full dose | 1% |
| EU maximum permitted concentration | 1.0% (1%) |
| EU Cosmetics Regulation annex | III |
| EU status | restricted |
Why the amount matters, not just the presence
Most ingredient checkers tell you whether something is in the bottle. That is a smaller question than it sounds. Selenium Sulfide at 1% and selenium sulfide at a trace level are not the same ingredient in any way that affects your skin.
An ingredient list is ordered by quantity, so position carries real information. YARAI reads that position and scores accordingly, which is why the same ingredient can land differently in two different products.
The honest limit: a list gives order, not percentages. Estimating concentration from position is an estimate. It is a better estimate than ignoring position, and it is still an estimate. We would rather tell you that than let a number look more certain than it is.
Regulatory status
EU CosIng Annex III restricted substance. Max: 1%
Common questions
What does selenium sulfide do in a skincare product?
Effective anti-dandruff and anti-seborrheic active; FDA-approved OTC at 1%; can discolor treated hair; rinse thoroughly.
How much selenium sulfide should a product contain?
YARAI treats 1% as a full dose for this ingredient. Below that, the ingredient is present but is scored as contributing less. An ingredient list gives you the order of ingredients, not their percentages, so this is an estimate read from position rather than a measurement.
Is selenium sulfide restricted in the EU?
The EU Cosmetics Regulation permits this ingredient up to 1.0% in leave-on cosmetics, listed under III. 1%
When should I use selenium sulfide?
Found in anti-dandruff shampoos (rinse-off, AM and PM appropriate). Rinse thoroughly after use. Do not allow prolonged skin contact. Prescription-strength (2.5%) requires dermatologist supervision. OTC 1% is available for regular dandruff control. Discolors bleached, tinted, or gray hair. Leave on briefly and rinse thoroughly.
Check your own products
Point your camera at a product. YARAI identifies it from the label, finds that product's full ingredient list from published sources, and scores it. No barcode and no box needed, which is how it handles imported and small-brand products.
Concern level, category and thresholds on this page are read directly from the same data the YARAI app scores with, so this page and the app cannot disagree. EU figures cite Regulation (EC) No 1223/2009. Last built 2026-09-09. Nothing here is medical advice.