Shampoo is a wash, not a treatment.

Name: AskDoc
Creator: AskDoc Medical Team

The right one costs little and depends on your scalp, not on the promises printed on the bottle.

Match the scalp, ignore the promises

Oily scalp: wash more often, any gentle shampoo. Dry or afro-textured hair: wash less often, milder formulas, conditioner doing most of the work. Flaky, itchy scalp: that is dandruff, a treatable condition, and it needs a medicated shampoo, not a prettier bottle. Words like nourishing, repairing and strengthening on a label have no regulated meaning at all.

The dandruff fix most people miss

Shampoos with ketoconazole, zinc pyrithione or selenium sulfide actually treat the cause, a yeast every scalp carries. The trick is contact time: lather, leave for two to three minutes, then rinse. Used twice a week, most dandruff is controlled within a month for a few dollars.

When it is not dandruff

Thick scale, red patches beyond the hairline, or itching that medicated shampoo does not touch can be psoriasis or eczema, and hair falling with the flakes deserves a professional look. A photo of your scalp is enough for our dermatologist review to tell you what it is and what to do, in writing, within 24 hours.

For flakes and an itchy scalp

Dandruff is a scalp condition, not a hygiene problem, and shampoos with ketoconazole, zinc pyrithione or selenium sulfide treat it. Leave it on the scalp two to three minutes before rinsing; that contact time is most of the trick.

See medicated shampoos

Hair loss and hair health Get your scalp looked at, $39 Skin and hair questions, answered

Common questions

How often should I wash my hair?

As often as your scalp gets oily, which for most people is every one to three days, and for curly or afro-textured hair often weekly. There is no medical rule; the scalp, not the calendar, decides.

Are sulfate-free shampoos better?

Sulfates are safe cleansers; sulfate-free versions are simply milder and can suit dry, curly or color-treated hair. For an oily scalp the regular kind cleans better. It is preference, not health.

Which dandruff shampoo works best?

Ketoconazole, zinc pyrithione and selenium sulfide all work; ketoconazole has the strongest evidence. Whichever you pick, leave it on the scalp two to three minutes before rinsing, and give it four weeks.

Written by the AskDoc Medical Team. We take no money from any brand; picks are what doctors tell patients to look for.