What are the common evidence-based vitamin and mineral deficiencies associated with hair fall?

Evidence-Based Vitamin and Mineral Deficiencies in Hair Loss

The three most consistently documented micronutrient deficiencies associated with hair loss are vitamin D, zinc, and folate, though the evidence quality remains limited by small retrospective studies. 1

Primary Deficiencies with Strongest Evidence

Vitamin D Deficiency

• Vitamin D deficiency (defined as ≤20 ng/mL) shows the strongest association with hair loss, particularly in alopecia areata, with deficiency rates of 83.3% in affected patients versus 23.3% in controls. 2
• Multiple case-control studies demonstrate an inverse correlation between vitamin D levels and disease severity in alopecia areata. 2
• A 2024 study found 79.17% of patients with diffuse hair fall were vitamin D3 deficient (mean level 17.33 ± 5.43 ng/ml). 3
• Check serum 25-hydroxyvitamin D levels in all alopecia patients, especially those with alopecia areata. 2

Zinc Deficiency

• Serum zinc levels tend to be lower in alopecia areata patients compared to controls, with levels inversely associated with disease severity. 1, 2
• In patients with serum zinc below 70 μg/dL, 50 mg zinc gluconate daily led to therapeutic improvement in 60% of patients at 12 weeks, though this was a small uncontrolled study. 2
• One double-blind placebo-controlled trial using 220 mg zinc sulfate twice daily showed no improvement despite increased serum zinc levels, highlighting conflicting evidence. 1, 2
• Measure serum zinc levels in alopecia patients, particularly those with alopecia areata. 2

Folate Deficiency

• RBC folate levels (not serum folate) are lower in alopecia areata patients and correlate negatively with disease severity. 2
• Check RBC folate rather than serum folate for accurate assessment of long-term folate stores. 2

Secondary Deficiencies with Gender-Specific or Conflicting Evidence

Iron Deficiency

• Evidence for iron deficiency in hair loss is highly gender-dependent and conflicting—only 2 of 8 studies supported an association with alopecia areata, primarily in female subjects. 1, 4
• For diffuse telogen hair loss and androgenetic alopecia, evidence is much stronger, with multiple studies showing lower ferritin levels in affected female patients. 4, 2
• Ferritin ≤15 μg/L confirms iron deficiency with 98% specificity in premenopausal women. 4
• Without inflammation, ferritin <30 μg/L or transferrin saturation <16% defines iron deficiency. 4
• Critical caveat: Ferritin is an acute-phase reactant and can be falsely elevated during infection, inflammation, chronic disease, malignancy, or liver damage—always assess CRP or ESR alongside ferritin. 4
• Check serum ferritin specifically in women with hair loss; routine iron testing is NOT recommended for alopecia areata in men. 4, 2

Vitamin B12

• Current evidence is insufficient to recommend routine vitamin B12 screening—multiple case-control studies found no differences in B12 levels between alopecia areata patients and controls. 2
• Check vitamin B12 only if pernicious anemia is suspected clinically. 2

Micronutrients with Insufficient Evidence

Not Recommended for Routine Screening

• Copper, magnesium, and selenium: Current evidence is insufficient to recommend routine screening or supplementation, as studies have yielded conflicting results with no consistent association with alopecia areata. 2
• Vitamin A: Only a small number of studies suggest vitamin A levels may modify disease, but evidence is inadequate for clinical recommendations. 1

Practical Clinical Algorithm

For any patient presenting with hair loss:

1. Always check: Serum 25-hydroxyvitamin D, serum zinc, and RBC folate 2
2. Check in women only: Serum ferritin (with CRP or ESR to assess for inflammation) 4, 2
3. Check selectively: Vitamin B12 only if pernicious anemia suspected 2
4. Do NOT routinely check: Copper, magnesium, selenium, or vitamin A 2

Critical Caveats and Limitations

• The current body of literature largely consists of small case-control studies and case reports which preclude definite conclusions for a role of micronutrients in hair loss. 1, 2
• Reverse causation is possible—hair loss may lead to lifestyle changes affecting micronutrient levels. 2
• Serum micronutrient levels may not accurately reflect tissue bioavailability. 2
• Few randomized controlled trials exist for micronutrient supplementation in alopecia treatment. 2, 5
• Many studies use combination therapies, making it difficult to definitively attribute efficacy to individual supplement components. 2
• Definitive clinical recommendations for routine serum level testing or therapeutic supplementation require additional studies in larger populations with prospective design. 1