Best Supplements for Hair Loss: Find the Cause First
Iron, vitamin D and zinc help hair loss only when you're deficient. Biotin rarely helps. Minoxidil and other treatments work better. See what to test.
By the editorial team · Updated Oct 14, 2026 · 2 sources cited
The best supplements for hair loss correct a deficiency that's contributing to shedding, most often low iron, but also vitamin D or zinc. Biotin helps only in rare deficiency and can distort lab tests. For pattern hair loss, proven treatments such as minoxidil work better than any supplement.
Evidence-ranked options
| Supplement | Evidence | Typical dose | Notes |
|---|---|---|---|
| Iron (low ferritin) | B | As advised after a blood test | Linked to shedding, especially in women. |
| Vitamin D (if low) | C | 600–2,000 IU | Associated with some hair loss types. |
| Zinc (if low) | C | 15–25 mg | Too much zinc can also cause hair loss. |
| Biotin | D | Not recommended without deficiency | Interferes with lab tests. |
A: strong · B: moderate · C: limited or mixed · D: good evidence of no benefit. See the evidence database.
Causes to check
Pattern hair loss, thyroid disease, low iron, recent illness or stress, autoimmune conditions and medications. See a doctor or dermatologist for a diagnosis. Our broader hair and nails guide covers collagen and nail health.
Ingredient guides
Frequently asked questions
Can stress cause hair loss?
Yes. Telogen effluvium often follows illness, surgery, childbirth or major stress by 2–3 months, and usually recovers on its own.
How long until hair grows back after fixing iron?
Hair grows slowly; expect to wait 3–6 months to see a difference.
Sources
Educational content, not medical advice. Read our medical disclaimer.