Vitamin Deficiencies in Alopecia

Primary Screening Recommendations

The American Journal of Clinical Dermatology recommends checking serum 25-hydroxyvitamin D levels in all alopecia patients, particularly those with alopecia areata, as vitamin D deficiency is strongly associated with hair loss 1, 2, 3
Multiple case-control studies demonstrate significantly lower vitamin D levels in alopecia areata patients (83.3% deficiency rate) compared to controls (23.3% deficiency rate), with a strong inverse correlation between vitamin D levels and disease severity 1, 4
The American Journal of Clinical Dermatology suggests measuring serum zinc levels, as zinc deficiency is associated with alopecia areata, and combined zinc supplementation with biotin and topical therapy has shown 33.3% complete regrowth in some patients 1, 5
The American Journal of Clinical Dermatology recommends checking RBC folate rather than serum folate for accurate assessment of long-term folate stores, as RBC folate levels are lower in alopecia areata patients and correlate negatively with disease severity 6, 7, 8

The American Journal of Clinical Dermatology notes that evidence is conflicting and gender-dependent for iron deficiency in alopecia, but lower ferritin levels are found primarily in female patients with alopecia areata and androgenetic alopecia 6, 7, 8
The American Journal of Clinical Dermatology states that current evidence is insufficient to recommend routine iron screening in all alopecia patients, but considers checking ferritin specifically in women with hair loss 7, 8
The American Journal of Clinical Dermatology does not recommend routine screening for vitamin B12, as multiple case-control studies found no differences in B12 levels between alopecia areata patients and controls, except in cases of suspected pernicious anemia 6, 7, 8, 9

For any patient presenting with alopecia, the American Journal of Clinical Dermatology recommends always checking serum 25-hydroxyvitamin D, serum zinc, and RBC folate, and checking serum ferritin in women only 1, 3, 6, 7, 8
The American Journal of Clinical Dermatology suggests checking vitamin B12 only if pernicious anemia is suspected clinically 9, 8

The American Journal of Clinical Dermatology notes that most evidence comes from small retrospective case-control studies, limiting generalizability, and that reverse causation is possible, where hair loss may lead to lifestyle changes affecting micronutrient levels 1, 4, 10
The American Journal of Clinical Dermatology states that serum micronutrient levels may not accurately reflect tissue bioavailability, and that few randomized controlled trials exist for micronutrient supplementation in alopecia treatment 1, 4, 7, 8

The American Academy of Dermatology supports checking serum zinc levels as zinc deficiency is associated with alopecia areata and serum levels appear inversely associated with disease severity 11
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 study without placebo control 12
The only double-blind, placebo-controlled trial using 220 mg zinc sulfate twice daily for 3 months showed no improvement despite increased serum zinc levels, highlighting the need for more rigorous studies 12
Current evidence is insufficient to recommend routine screening or supplementation with copper, magnesium, or selenium, as studies have yielded conflicting results with no consistent association with alopecia areata 12

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 alopecia areata 11
Many studies use combination therapies making it difficult to definitively attribute efficacy to individual supplement components 12