What supplements are recommended for treating hair loss?

Hair Loss Supplement Recommendations

For hair loss supplements, I recommend checking vitamin D, zinc, and folate levels first, then supplementing only if deficient—routine supplementation without documented deficiency is not supported by evidence. 1, 2

Diagnostic Testing Before Supplementation

Before recommending any supplements, obtain targeted laboratory testing:

• Serum 25-hydroxyvitamin D (check in all patients with hair loss) 1, 2
• Serum zinc levels (particularly for alopecia areata patients) 1, 2
• RBC folate (not serum folate, as RBC folate better reflects long-term stores) 2
• Serum ferritin (in women only, as evidence is gender-dependent) 2

Do not routinely check vitamin B12 unless pernicious anemia is clinically suspected, as multiple studies found no differences in B12 levels between alopecia patients and controls. 2

Evidence-Based Supplementation Recommendations

Vitamin D

Supplement only if levels are <20 ng/mL (<50 nmol/L). 2

• 70% of alopecia areata patients are deficient versus 25% of controls 1, 2
• Lower vitamin D levels correlate inversely with disease severity 1, 2
• The vitamin D receptor plays a critical role in hair follicle cycling 1
• Critical caveat: No double-blind trials have examined oral vitamin D supplementation as a treatment strategy for alopecia areata, so supplementation addresses deficiency but efficacy for hair regrowth remains unproven 1

Zinc

Supplement only if serum levels are low, particularly if <70 μg/dL. 3

• Serum zinc levels tend to be lower in alopecia areata patients, especially those with resistant disease >6 months duration 3, 1
• The only double-blind, placebo-controlled trial (220 mg zinc sulfate twice daily for 3 months) showed no improvement in alopecia areata despite increased serum zinc levels 3
• One small uncontrolled study showed 60% improvement with 50 mg zinc gluconate daily in patients with zinc levels <70 μg/dL, but this lacked statistical significance and had no placebo group 3
• Evidence is insufficient to recommend routine zinc supplementation without documented deficiency 3

Folate

Supplement only if RBC folate levels are low. 2

• RBC folate levels are lower in alopecia areata patients and correlate negatively with disease severity 2
• Folate deficiency may contribute to hair loss 1

Iron

Supplement only in women with low ferritin levels. 2

• Lower ferritin levels are found primarily in female patients with alopecia areata and androgenetic alopecia 2
• Evidence is conflicting and gender-dependent 2
• Current evidence is insufficient to recommend routine iron screening in all alopecia patients 2

Supplements NOT Recommended

Biotin

Do not routinely recommend biotin supplementation for hair loss. 4, 5

• No clinical trials have investigated biotin supplementation for treating alopecia of any kind 5
• No randomized controlled trials exist studying its effect on hair quality and quantity in humans 5
• Only 38% of women complaining of hair loss have biotin deficiency 4
• Biotin's popularity is vastly disproportionate to insufficient clinical evidence supporting its efficacy 5
• Indiscriminate biotin supplementation should be rejected unless deficiency is documented 4

Copper, Magnesium, and Selenium

Do not routinely supplement these minerals. 3

• Few studies have identified an association between low levels and alopecia areata 3
• Most studies found no differences in copper or magnesium levels between alopecia patients and controls 3
• Evidence for selenium is conflicting between studies 3

First-Line Medical Treatments (Not Supplements)

For androgenetic alopecia (pattern hair loss), the evidence-based treatments are:

• Topical minoxidil 5% (for men) or 2% (for women) applied twice daily 6, 7, 8
• Oral finasteride (for men only; not for use by women) 7, 8

These FDA-approved medications have substantially more evidence than any supplement. 6, 8

Common Pitfalls to Avoid

• Ordering excessive laboratory tests when not indicated—focus on vitamin D, zinc, RBC folate, and ferritin (women only) 2
• Supplementing without documented deficiency—most micronutrient evidence comes from small retrospective studies with limited generalizability 2
• Assuming serum levels reflect tissue bioavailability—serum micronutrient levels may not accurately reflect what's happening at the hair follicle 2
• Ignoring reverse causation—hair loss may lead to lifestyle changes that affect micronutrient levels, not the other way around 2
• Recommending biotin based on marketing rather than evidence—social media hype does not equal clinical efficacy 5