What to watch with Zink and fertility?

Zinc is an essential trace element for fertility in both sexes: it supports sperm quality, ovulation, and immune function. However, caution is needed: the safe upper limit for zinc from supplements is 40 mg/day for adults (including pregnancy). Higher doses can cause copper deficiency, nausea, and immune impairment. DNA tests for zinc transporters (e.g., SLC30A) or metallothioneins (MT) currently have no clinically proven relevance for individual zinc dosing. The evidence for zinc and fertility comes mostly from observational studies and small trials; large RCTs are lacking. Zinc deficiency should be confirmed via blood testing (serum zinc) before supplementing. For unexplained infertility, comprehensive medical evaluation is more important than isolated supplementation.