Hair Loss and Zinc Deficiency: A Cross-Sectional Study

Highlights: What are the main findings? Patients with hair loss had slightly lower median zinc levels than controls (96 vs. 99 µg/dL, p-value < 0.001), but the difference was minor, not clinically significant, and both were within the normal range. Patients with hair loss had slightly lower median ferritin (30.0 vs. 33.0 µg/L, p = 0.001) and hemoglobin levels (12.9 vs. 13.1 g/dL, p < 0.001) compared to controls, though the differences were small and of limited clinical relevance. What is the implication of the main finding? Routine zinc testing is not recommended when evaluating hair loss, as the minor decrease observed in zinc levels among patients lacked clinical significance. Background: Hair loss is a common complaint, especially in the primary care setting. Despite conflicting results in previous studies regarding the role of zinc in hair loss, zinc levels are being widely tested as part of an initial laboratory investigation for hair loss. Objectives: We aimed to investigate whether lower zinc levels were associated with patients’ complaints of hair loss. Methods: In this retrospective cross-sectional study, we collected data on the zinc levels of patients diagnosed with hair loss who underwent a zinc level test after their diagnosis. The zinc levels of these patients were compared to those of a control group, which included patients who were also investigated for zinc levels for reasons other than hair loss. Results: Between 2000 and 2020, 23,975 eligible patients were included in this study. Among these patients, 9.5% (N = 2279) had a diagnosis of hair loss and a median zinc level of 96 µg/dL (84.0–110.0), compared to 99 µg/dL (85.0–115.0) in the control group (p < 0.001). Conclusions: This cross-sectional study investigated the relationship between zinc levels and complaints of hair loss. While we do report lower zinc levels in those with hair loss complaints, this change is minor and lacks clinical significance. As the standard today, we suggest that zinc levels should not be obtained as a laboratory test when investigating hair loss. Further studies on the efficacy of zinc supplements in hair loss could elucidate the clinical relevance of zinc in hair loss conditions.