The Science Behind Hair Supplements

Therapeutic dose: 450 mg twice daily (900 mg total)

See ranked AminoMar Marine Complex (Viviscal) products→

• Multiple double-blind, placebo-controlled RCTs demonstrated significant increases in terminal hair count, reduced shedding, and improved hair density at 90 and 180 days
• 6-month RCT in men showed significant increases in total hair count, total hair density, and terminal hair density
• 2015 double-blind RCT (60 women) showed significantly increased hair growth and decreased shedding at 90 and 180 days vs placebo
• In vitro studies show AminoMar enhances dermal papilla cell proliferation and increases alkaline phosphatase (anagen phase marker)

Therapeutic dose: 18–65 mg/day (when deficient)

See ranked Iron products→

• Iron deficiency is one of the most common causes of hair loss, especially in women — low ferritin strongly associated with telogen effluvium
• Supplementation restores hair growth when ferritin is low, but no benefit when levels are adequate
• Dermatology guidelines recommend checking ferritin in all women presenting with diffuse hair loss

Therapeutic dose: 15–30 mg/day

See ranked Zinc products→

• Multiple studies show significantly lower serum zinc in patients with hair loss (telogen effluvium, alopecia areata)
• Clinical trial showed 50 mg zinc gluconate daily improved hair in zinc-deficient patients with androgenic alopecia after 12 weeks
• No high-quality evidence that zinc supplementation benefits hair in non-deficient individuals

Therapeutic dose: 1,000–2,000 mg combined EPA/DHA

See ranked Omega-3 Fatty Acids (EPA/DHA) products→

• 6-month RCT (120 women) showed fish oil + antioxidant supplementation improved hair density and reduced telogen percentage vs placebo
• Anti-inflammatory effects may reduce follicular inflammation associated with pattern hair loss

Therapeutic dose: 400 mg/day

See ranked Pumpkin Seed Oil products→

• RCT (76 men, 24 weeks) showed 400 mg/day increased hair count by 40% vs 10% in placebo — statistically significant
• Proposed mechanism: 5-alpha reductase inhibition (anti-androgenic), similar to finasteride but weaker
• Limited to single study in androgenic alopecia — needs replication

Therapeutic dose: 1,000–4,000 IU/day

See ranked Vitamin D products→

• Low vitamin D levels associated with alopecia areata, telogen effluvium, and female pattern hair loss in observational studies
• Vitamin D receptors are present in hair follicles and involved in hair cycle regulation
• No RCTs demonstrating that supplementation treats hair loss when not deficient

Therapeutic dose: 1,000–3,000 mg/day

See ranked MSM (Methylsulfonylmethane) products→

• Provides bioavailable sulfur needed for keratin disulfide bonds in hair structure
• Small studies suggest possible benefits for hair and nails, but no robust RCTs exist

Therapeutic dose: 0.5–2 mg/day

See ranked Copper products→

• Essential for tyrosinase (melanin production) — copper deficiency causes premature graying
• Copper deficiency causes characteristic 'kinky' hair (pili torti) as seen in Menkes syndrome
• No supplementation RCTs for hair outcomes in non-deficient individuals

Therapeutic dose: 5–20 mg/day

See ranked Silica (Silicon) products→

• One study showed silicon supplementation improved hair tensile strength and thickness
• Limited high-quality clinical data for hair-specific outcomes

Therapeutic dose: 100–400 IU/day

See ranked Vitamin E products→

• One small RCT (38 volunteers, 8 months) showed tocotrienol supplementation increased hair count by 34.5% vs placebo
• Single study only — needs replication with larger sample size

Therapeutic dose: 2,500–10,000 mg/day

• Zero RCTs demonstrating collagen supplementation improves hair growth or reduces hair loss
• Harvard Health states there is 'no medical evidence' supporting marketing claims of collagen for hair
• Provides glycine and proline which are theoretically useful for keratin, but no clinical evidence of benefit

Therapeutic dose: Not established

See ranked Keratin (Oral) products→

• A few small studies show some improvements in hair strength metrics, but no robust placebo-controlled RCTs exist
• Oral bioavailability of intact keratin is poorly understood — likely digested into amino acids

Therapeutic dose: 30–100 mcg/day (DV level)

See ranked Biotin (Vitamin B7) products→

• 2017 systematic review found zero RCTs proving biotin efficacy for hair growth in healthy, non-deficient individuals
• 2024 review confirmed a large discrepancy between public perception of biotin's efficacy and the scientific literature
• Highest-quality double-blind, placebo-controlled study found no difference between biotin and placebo for hair growth
• AAD released a cautionary statement against biotin as a primary treatment for hair growth
• High-dose biotin (>100 mcg/day) interferes with immunoassay laboratory tests (thyroid, cardiac markers)