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Hair honesty, from people with no serum to sell.

Most hair products promise growth. Two things have evidence. Here is the whole picture.

First, find the reason

Sudden shedding usually follows the body a few months behind a stressor: illness, crash dieting, childbirth, new medicines. That kind regrows on its own. Gradual thinning at the temples or crown is usually hereditary. And low iron or thyroid problems quietly thin hair too, which is why a blood test beats a shopping trip when hair falls fast.

What has real evidence

Two treatments, and neither is a shampoo: minoxidil applied to the scalp, and for men, finasteride from a doctor. Both take four to six months to show and work only while used. Everything else with evidence is unglamorous: enough protein, corrected iron, treated thyroid, and gentleness with heat and tight hairstyles.

What the aisle sells anyway

Biotin does nothing unless you are deficient, which is rare. Caffeine shampoos, growth gummies and collagen have marketing, not trials. Money spent there is better spent on the blood test, or on a dermatologist looking at your actual scalp: our photo review does exactly that in writing for $39.

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

Common questions

How much hair loss is normal?
Losing 50 to 100 hairs a day is normal. Worry when the ponytail feels thinner, the part widens, or shedding suddenly doubles for more than a couple of months; those deserve a look for iron, thyroid and pattern loss.
Does biotin help hair growth?
Only if you are deficient, which is rare. In everyone else trials show no benefit. Protein, iron and treating the underlying cause matter far more.
Can hair grow back after thinning?
Shedding from stress, illness or low iron regrows over months once the cause is fixed. Hereditary thinning does not reverse on its own, but minoxidil and prescription options can regrow some and hold the rest.

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

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