Zinc for Male Fertility

What does the evidence say about zinc while trying to conceive?

1. The largest trial on this question, an NIH-funded, randomized, placebo-controlled study of 2,370 couples working with fertility clinics across four U.S. cities, found daily zinc plus folic acid produced live birth rates nearly identical to placebo, 34 percent versus 35 percent, with no improvement in sperm movement, shape, or count, and more men taking the supplement reported nausea, vomiting, and abdominal discomfort than men taking placebo. 1
2. A broader 2025 scientific review of zinc and male infertility found real but inconsistent signals across smaller trials: about 66 milligrams a day for six months was linked to a better sperm count in one trial, and 220 milligrams of zinc sulfate twice daily for three months was linked to better sperm motility and shape in another, though the same review notes that high zinc levels can trigger oxidative stress and that benefit shows up mainly in men who started out zinc-deficient. 2
3. The standard recommended intake for zinc is just 11 milligrams a day for adult men and 8 milligrams for adult women, with a tolerable upper limit of 40 milligrams a day for adults, so several of the higher doses used in fertility trials run well past what's considered a routine, well-tolerated amount. 3
4. Doses well above the upper limit carry their own risks: single doses of 1 to 2 grams can cause vomiting, nausea, and abdominal pain, while sustained high intake can lead to copper deficiency, anemia, and low white-blood-cell counts, since the body responds to zinc excess by binding and clearing copper instead of zinc. 4
5. Zinc supplementation might help some men but not others, according to a synthesis of the male-fertility research, and taking more than the 40 milligram upper limit isn't recommended given how limited that research still is. 5

What to know about zinc while trying to conceive

• If you're just starting to try and already take a multivitamin with zinc in it, there's no research reason to add more. The mineral concentrates naturally in semen and plays a role in normal cell division, but the largest trial on extra zinc for fertility found no benefit over a standard diet and multivitamin.
• A few months into actively trying, zinc shows up in a lot of fertility-focused supplement blends marketed to men, sometimes at doses far above the standard amount. The trials that found a benefit used anywhere from about 66 to 440 milligrams a day, well past the 40 milligram upper limit, and haven't been confirmed in a large trial, so stacking products can push you over that limit without realizing it.
• If trying has stretched on without success, that's a reason to loop in a fertility specialist for a full evaluation, including semen analysis, rather than continuing to adjust supplements alone. Zinc deficiency is only one of many possible factors behind male infertility, and a provider can tell you whether your zinc status is actually part of the picture.

Zinc doses studied for male fertility