Best Supplements for Hair Loss
What actually helps — and what's just expensive urine. Evidence-ranked supplements for thinning hair, with real doses and honest expectations.
Hair loss has many causes — genetics, hormones, nutrient deficiencies, stress, thyroid issues. The right supplement depends entirely on why your hair is thinning. Step one is always figuring out the cause, not reaching for biotin.
This guide is for you if: You're noticing more hair in the drain, thinning at the crown or temples, post-pregnancy hair loss, or diffuse thinning and want to know what's worth trying.
See the evidence for each supplementFirst: what kind of hair loss?
This matters because different causes need different solutions:
- Androgenetic alopecia (genetic, pattern baldness) — DHT-driven. Best addressed with finasteride/minoxidil. Supplements like saw palmetto can help modestly.
- Telogen effluvium (diffuse shedding after stress, illness, or deficiency) — Often caused by low iron, zinc, vitamin D, or thyroid issues. Supplements can be very effective here.
- Nutritional deficiency — Low ferritin, zinc, biotin, or vitamin D can all cause hair loss. Correcting the deficiency usually stops the shedding within 3–6 months.
- Thyroid-related — Both hypo- and hyperthyroidism cause hair loss. Fix the thyroid, and the hair recovers.
Top supplements by cause
| Supplement | Dose | Best for | Evidence |
|---|---|---|---|
| Iron (bisglycinate) | 25–50 mg/day | Low ferritin hair loss | Strong (if deficient) |
| Vitamin D3 | 2,000–4,000 IU/day | Deficiency-related thinning | Strong (if deficient) |
| Zinc | 15–30 mg/day | Diffuse shedding, zinc deficiency | Strong (if deficient) |
| Saw palmetto | 320 mg/day | Male pattern baldness (mild) | Moderate |
| Biotin | 2,500–5,000 mcg | Only if biotin-deficient | Weak (unless deficient) |
| Collagen peptides | 5–10 g/day | Hair structure, thickness | Moderate |
| Omega-3 | 1–2 g/day | Scalp inflammation | Moderate |
Get ferritin, vitamin D, zinc, thyroid panel (TSH, FT3, FT4), and a CBC tested first. This single panel identifies the most common correctable causes of hair loss in India.
If ferritin is below 30, start with iron bisglycinate + vitamin C. If vitamin D is below 30, start with D3. These alone resolve many cases.
Which labs to check
- Ferritin — aim for >70 ng/mL for hair health (not just "normal range")
- Vitamin D (25-OH) — aim for 40–60 ng/mL
- Zinc (serum or RBC) — deficiency is common in vegetarians
- Thyroid panel (TSH, Free T3, Free T4) — subclinical thyroid issues often missed
- CBC — to check for anaemia
- DHT (if male pattern baldness suspected) — confirms androgenetic component
High-dose biotin supplements (5,000–10,000 mcg) can interfere with blood test results — falsely elevating thyroid hormones, falsely lowering TSH, and affecting troponin tests. If you're supplementing biotin, stop it 48–72 hours before any bloodwork.
Find out why your hair is thinning
eterni helps you get the right tests, interpret results, and track progress after supplementation — all in one place.
Get early accessFrequently Asked Questions
Does biotin actually help hair loss?
Only if you're deficient — which is uncommon. Biotin deficiency causes hair loss, but supplementing with biotin when your levels are normal doesn't grow extra hair. True biotin deficiency is rare in people eating a balanced diet. Get your biotin tested before supplementing, as excess biotin can also interfere with lab results.
What is the best supplement for male pattern baldness?
Saw palmetto (320 mg/day) is the best-studied supplement for androgenetic alopecia in men. It mildly inhibits 5-alpha reductase (the same enzyme finasteride targets) with fewer side effects. However, it's significantly weaker than finasteride — expect modest slowing of hair loss rather than regrowth.
Can iron deficiency cause hair loss?
Yes, and it's one of the most common correctable causes of hair loss, especially in women. Ferritin (stored iron) below 30 ng/mL is associated with increased hair shedding. Many dermatologists aim for ferritin above 70 ng/mL for optimal hair health. Get your ferritin checked — it's the most important iron marker for hair.
Should I take finasteride or try supplements first?
If you have confirmed androgenetic alopecia (male pattern baldness), finasteride is far more effective than any supplement. Supplements like saw palmetto, zinc, and iron are best for nutritional hair loss, stress-related shedding, or as adjuncts alongside finasteride/minoxidil. Don't waste years on supplements if your hair loss is genetic and progressing.
The science of hair growth
Hair follicles cycle through growth (anagen, 2–7 years), regression (catagen, 2–3 weeks), and rest (telogen, 3 months). At any time, about 90% of your hair is in the growth phase. When something disrupts this cycle — stress, nutrient deficiency, hormonal changes — more follicles enter the resting phase simultaneously, causing noticeable shedding 2–3 months later.
Iron and ferritin are critical because hair follicle cells are among the fastest-dividing cells in the body, requiring adequate iron for DNA synthesis. When iron stores drop, the body prioritises vital organs over hair growth. This is why ferritin below 30 ng/mL (even though lab "normal" ranges start at 10–15) correlates with hair loss in studies.
Saw palmetto contains fatty acids and phytosterols that inhibit 5-alpha reductase, reducing the conversion of testosterone to DHT. In a 24-month study, 38% of men taking 320 mg/day showed increased hair growth compared to 68% with finasteride. It's weaker but has fewer side effects.
Stop guessing. Start testing.
eterni connects your labs to your supplements — so you can see exactly what's helping your hair and what's not.
Join the waitlist