Effects of Zinc Sulfate on Subfertility Related to Male Factors: A Prospective Double-Blind, Randomized, Placebo-Controlled Clinical Trial

Background Different studies found that zinc is necessary for sexual maturity, growth and fertility. But there are no distinct studies that clarify the role of zinc supplements on semen parameters. Objectives The current study aimed to evaluate the zinc supplement therapeutic effects on semen samples of infertile males. Patients and Methods The study comprised one-hundred-twenty sub fertile males. The study was a double-blinded placebo-controlled clinical trial. The subjects were randomly allocated to treatment with zinc supplement (n = 60) or placebo (n = 60) groups. Subjects in both groups were given 10 mL, three times daily. In order to determine the sperm concentration, Motility and morphology, standardized semen and blood samples were obtained before and after treatment, according to the World Health Organization (WHO) guidelines; semen morphology according to strict criteria, and blood and semen zinc concentration also were measured. Effects of the two interventions were evaluated in sub fertile males. Results Sub fertile males demonstrated a significant increase (8.8 ± 7.4 × 10⁶ cells/mL to 17.2 ± 13.5 × 10⁶ cells/mL) in concentration and normal sperm in zinc group versus the placebo group. Blood serum zinc concentration increased in the interventional group significantly (P = 0.000), and also semen plasma zinc concentration increased significantly (P = 0.000). Conclusions Normal sperm percentage and total sperm concentration increased after zinc sulfate treatment. The beneficial effect of zinc and all results of the current study opened new way to medical purposes and public health researches.