Supplements for Hair Growth
The evidence does not support routine supplementation for hair growth in the absence of documented micronutrient deficiencies, and the only proven treatments remain topical minoxidil and oral finasteride. 1, 2
Evidence-Based Approach to Supplementation
Test Before Supplementing
The critical first step is laboratory confirmation of deficiency rather than empiric supplementation:
Check serum ferritin levels in patients with hair loss, particularly women, as iron deficiency may impair treatment response in androgenetic alopecia when corrected, though target levels remain debated (some recommend ≥70 μg/L with normal ESR). 1, 3
Measure serum zinc levels if deficiency is suspected, as four out of six case-control studies found lower zinc in hair loss patients, though supplementation evidence is weak. 1, 4
Consider vitamin D testing, as lower levels associate with hair loss, though evidence for supplementation efficacy is limited to small trials primarily in alopecia areata, not pattern baldness. 1, 4
B vitamins (folate, B12) testing has insufficient evidence to support routine measurement or supplementation for hair loss. 1, 4
Zinc Supplementation: Inconsistent Evidence
The data on zinc reveals significant limitations:
The only double-blind, placebo-controlled trial showed no benefit when 220 mg zinc sulfate twice daily for 3 months increased serum zinc but failed to improve alopecia areata. 4
One small uncontrolled study suggested 50 mg zinc gluconate daily helped 60% of alopecia areata patients with serum zinc <70 μg/dL, but lacked statistical significance and placebo control. 4
Zinc supplementation should only occur with documented deficiency, as the American Journal of Clinical Dermatology concludes there is insufficient evidence for routine zinc supplementation. 1, 4
Vitamin D: Limited to Alopecia Areata
Topical vitamin D analogs show promise only in specific contexts:
Small trials of topical calcipotriol 0.005% twice daily showed 59-75% of alopecia areata patients had regrowth, but these lacked placebo controls and involved patchy alopecia areata, not male pattern baldness. 4
No double-blind trials have examined oral vitamin D supplementation for prevention or treatment of any hair loss type. 4
Critical Pitfalls to Avoid
Distinguish Hair Loss Types
The evidence base differs dramatically between alopecia areata (autoimmune) and androgenetic alopecia (pattern baldness)—most supplement studies address alopecia areata, making extrapolation to pattern baldness inappropriate. 1
Risks of Unsupervised Supplementation
Excessive supplement intake may actually cause hair loss rather than treat it, as supplements are regulated as foods without required safety or efficacy proof. 5, 3
Potential harms include acute toxicities, chronic toxicities (increased diabetes risk), teratogenicity, drug interactions, and allergic reactions. 5
Self-medicating without testing for deficiencies can be harmful and delays proven treatments. 1
Supplements as Adjunctive Only
Supplements should be viewed as adjunctive therapy to address nutritional deficiencies that may impair response to primary treatments (minoxidil, finasteride), not as standalone solutions. 1
Proven Treatments
The FDA-approved topical minoxidil 5% remains the dermatologist-recommended #1 active ingredient, clinically proven to reactivate hair follicles and stimulate regrowth. 2