What dandruff actually is
Dandruff is accelerated shedding of scalp skin cells, most often driven by a normal scalp yeast (Malassezia) that some scalps over-react to, plus excess oil. It is not caused by poor hygiene, it is not contagious, and dry scalp is only one of several causes — greasy scalps flake too.
The active ingredients that work
Ordinary shampoo washes flakes away for a day; anti-dandruff actives treat the cause. Look for one of these on the label, widely available over the counter:
| Ingredient | What it does |
|---|---|
| Zinc pyrithione | Anti-fungal + slows cell turnover; good first choice for mild cases |
| Ketoconazole | Strong anti-fungal; often the most effective for stubborn dandruff |
| Selenium sulfide | Anti-fungal + reduces oil; good for greasy-scalp flaking |
| Salicylic acid | Loosens thick, built-up scale so other actives can reach the scalp |
| Coal tar | Slows cell turnover; helpful for thick, persistent scale |
Technique matters as much as the bottle: massage into the scalp (not just the hair), leave for 3–5 minutes before rinsing, use 2–3 times a week for at least 4 weeks, and rotate ingredients if one stops working.
When it is more than dandruff
Red, inflamed, greasy-scaled patches — especially if they also appear on the eyebrows, sides of the nose, or behind the ears — suggest seborrheic dermatitis. Thick silvery scale on well-defined plaques may be scalp psoriasis. Both are common, both are manageable, and both deserve a dermatologist rather than trial-and-error.
Do diet and stress matter?
Stress reliably worsens flare-ups, and severe flares often follow stressful periods. Evidence on diet is weaker, but a balanced pattern supporting skin health — omega-3s, zinc, B vitamins, limited ultra-processed food — is a sensible companion to topical treatment.
Sources & references
- Borda LJ, Wikramanayake TC. Seborrheic dermatitis and dandruff: a comprehensive review. J Clin Investig Dermatol. 2015;3(2).
- American Academy of Dermatology. Seborrheic dermatitis: Diagnosis and treatment.
- Ranganathan S, Mukhopadhyay T. Dandruff: the most commercially exploited skin disease. Indian J Dermatol. 2010;55(2):130–134.