Can zinc or selenium deficiency cause diffuse hair loss?

Clinical evidence

Research into nutritional contributors to diffuse hair loss, specifically telogen effluvium, underscores a strong association with zinc deficiency, while the link to selenium deficiency is less frequently observed in clinical practice.

• Zinc status: Case-control studies highlight a significant correlation between low serum zinc and hair shedding. In one study of 312 patients, those with telogen effluvium demonstrated a 4.6-fold higher risk of zinc deficiency compared to control groups. However, meta-analyses suggest that while zinc levels are lower in these populations, the evidence for iron and vitamin D as drivers of hair loss is generally more robust.
• Selenium status: Clinical evidence linking isolated selenium deficiency to hair loss is primarily confined to extreme physiological states, such as severe malabsorption or long-term total parenteral nutrition lacking trace elements. In general populations, hair loss is actually more frequently documented as a symptom of selenium toxicity rather than deficiency.

Mechanistic explanations

Both minerals play essential roles in the biological lifecycle of the hair follicle, though through different pathways.

• Zinc's role: Zinc is a vital cofactor for over 300 enzymes, including those responsible for DNA and protein synthesis in hair matrix keratinocytes. The zinc transporter ZIP10 is specifically required to maintain p63 activity, a transcription factor that governs follicle development. Zinc-finger proteins also modulate the Wnt/β-catenin pathway, which is the primary driver for entering the anagen (growth) phase.
• Selenium's role: Selenium is incorporated into selenoproteins, such as glutathione peroxidase, which provide critical antioxidant defense for the hair follicle. These proteins protect the follicle from oxidative stress during the highly metabolic hair growth process. In animal models, the absence of these selenoproteins leads to impaired follicle differentiation and sparse hair growth.

Safety and clinical considerations

Supplementation should be approached with caution, as both minerals exhibit a narrow therapeutic window.

• Copper interference: Chronic, high-dose zinc supplementation can interfere with copper absorption, potentially leading to secondary copper deficiency, which itself is associated with hair loss and anemia.
• Toxicity risk: Selenium toxicity (selenosis) is a well-documented cause of sudden, diffuse hair loss and nail changes. Supplementation is typically only recommended when a clinical deficiency is confirmed via laboratory testing.

Bottom line

Zinc deficiency is a clinically supported risk factor for diffuse hair loss due to its role in follicular cell proliferation. Selenium deficiency is a plausible cause but is rare outside of severe malnutrition. For both minerals, supplementation is most effective when correcting a laboratory-confirmed deficiency, as excessive intake of either can paradoxically worsen hair loss.