How to choose a hair supplement — five things to read on the label

Before you pay for any bottle, turn it over. These five things tell you more than the front ever will.

By the medology pharmacist team · Reviewed by our hair specialists · 2026-10-10

1. Actual amounts, not ingredient names

A good label tells you the amount of the active element you really get — "Zinc Bisglycinate 75 mg, providing 15 mg zinc" — not just "contains zinc". It should also show %RDI so you can compare.

2. The form of each mineral

Chelated minerals (glycinates, for example) are usually gentler on the stomach than sulfates or oxides. That matters when you are taking something daily for months.

3. What is left out matters too

Excess vitamin A and selenium are linked to abnormal shedding (Almohanna 2019). If you already take a multivitamin, stacking bottles can push you over.

4. Registration number and manufacturer

In Thailand a supplement must carry a 13-digit FDA food serial number you can check on the FDA website. It should also name the manufacturer and the factory's standards, such as GHPs/HACCP.

5. Promises that are too big

Under Thai law a supplement may only make nutrition claims the FDA permits — for example, "biotin, zinc and selenium contribute to the maintenance of normal hair". A bottle that promises "new hair in 30 days" or "stops hair fall" is saying more than the evidence or the law allows.

And a sixth — time

Hair grows about 1 cm a month, so any change takes at least three to six months to notice. A good product tells you plainly how long to take it, and when to see a doctor instead.