Zinc is an essential mineral involved in protein synthesis, cell division, and immune function — all of which have relevance to hair follicle health. Its relationship with hair loss is better documented than many supplement ingredients, making it worth understanding in the context of a hair health strategy.
Zinc deficiency is associated with hair loss. Studies have shown that patients with androgenetic alopecia and alopecia areata have lower serum zinc levels than controls, and that correction of zinc deficiency in deficient patients improves hair loss outcomes. The mechanism involves zinc’s role as a cofactor for 5-alpha reductase inhibition — a function that partially overlaps with finasteride’s mechanism, though at a much smaller magnitude.
Zinc is also essential for the function of RNA and DNA polymerase in hair follicle cells, and for the structural proteins of the hair shaft itself. Deficiency disrupts these processes, causing brittle hair and increased shedding.
Who is most likely to be deficient? Vegetarians and vegans (plant-based zinc is less bioavailable than animal sources), patients with Crohn’s disease or malabsorption conditions, those on very low-calorie diets, and patients who had bariatric surgery.
For patients without deficiency, zinc supplementation is unlikely to produce significant benefit for hair loss beyond what is already being achieved through diet. A blood test to check serum zinc is a straightforward first step. If deficient, a supplement of 15 to 25 mg daily is appropriate; if not, the supplement is likely unnecessary.
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