Ketoconazole (Topical)
Topical ketoconazole is an antifungal shampoo (1-2%) widely used off-label as an adjunct for androgenetic alopecia. Beyond treating scalp seborrhea, it appears to exert a mild local anti-androgen effect and reduce scalp inflammation, supporting hair density when combined with finasteride or minoxidil.
01 Overview
Marketed as Nizoral among others, ketoconazole shampoo is primarily an antifungal for dandruff and seborrheic dermatitis. Small studies suggest 2% ketoconazole improves hair shaft diameter and density in androgenetic alopecia, likely via combined anti-inflammatory and mild anti-androgen action.
It is inexpensive, well tolerated topically, and commonly used two to three times weekly as an add-on rather than a standalone treatment. Systemic anti-androgen effects seen with oral ketoconazole do not meaningfully apply to shampoo use.
02 Mechanism
Inhibits fungal ergosterol synthesis (antifungal action) and locally interferes with androgen action and inflammation at the scalp; oral ketoconazole inhibits steroidogenesis, but topical systemic absorption is minimal.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Alopecia adjunct | 2 % | Transdermal | 2% shampoo, left on scalp ~3-5 min, 2-3 times weekly |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Improved hair density (adjunct)Small studies show increased hair shaft diameter and density with 2% shampoo. | Modest | Observational | |
| Reduced scalp inflammationTreats seborrheic dermatitis and dandruff, improving scalp environment. | Effective | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Scalp irritation / drynessDryness, itching, or changes in hair texture. | Mild | Common | Clinical | |
| Contact allergyAllergic contact dermatitis in sensitised users. | Mild | Rare | Clinical |