Zinc is a trace mineral the body needs for hundreds of enzymes, for immune function and for normal sperm production. It is found in meat, shellfish, dairy, beans, nuts and whole grains, and the prostate secretes it into seminal plasma in large amounts.
Zinc carries authorised UK and EU health claims that are directly relevant to men's sexual health: zinc contributes to normal fertility and reproduction, and zinc contributes to the maintenance of normal testosterone levels in the blood. Zinc also contributes to the protection of cells from oxidative stress.
Because of these roles, zinc is the most common ingredient in male fertility and semen volume supplements. A 2016 meta-analysis of 20 studies found that infertile men had lower seminal zinc than fertile men, and that zinc supplementation in infertile men was associated with higher semen volume, better sperm motility and a higher percentage of normally shaped sperm.1 The authors called for further studies to clarify the link.
What have studies found on zinc and semen volume?
Studies in infertile men have linked zinc supplementation with higher semen volume, as well as better motility and sperm shape. These were mainly smaller trials in men with fertility problems, many of whom had low seminal zinc.
The 2016 meta-analysis pooled studies of men with fertility problems, who on average had lower zinc in their semen than fertile men, and found supplementation was associated with improvements in semen volume, motility and morphology.1 We cover this in more detail in zinc and semen volume.
A larger trial published in 2020 randomised 2,370 men whose partners were planning fertility treatment to 30 mg of zinc plus 5 mg of folic acid daily, or a placebo, for six months. It did not find a difference in semen measures or live birth rates between the groups.2 Researchers are still working out which men are most likely to benefit, and starting zinc status is one of the questions being explored.
Who is most likely to be low in zinc?
People whose diet contains few zinc-rich foods, heavy drinkers and people with gut conditions that affect absorption. Men with lower seminal zinc were the main group in the studies that reported semen improvements.
The meta-analysis looked at infertile men, who on average had lower zinc in their semen than fertile men.1 If you think your intake may be low, a doctor can advise on whether testing makes sense, and a dietitian can help you check your diet.
- Diets that exclude most zinc-rich foods, such as meat, shellfish and dairy
- Gut conditions that affect absorption
- Heavy drinking
Is zinc safe to take?
At normal dietary amounts, yes. At high doses over weeks or months it can cause copper deficiency, which can lead to anaemia and nerve damage.
In the 2020 trial, stomach pain, nausea and vomiting were more common in the zinc group.2 A 2026 systematic review of 37 published cases found zinc-induced blood problems at reported doses from roughly 50 mg a day upwards, with low copper in every patient; blood counts usually recovered after stopping zinc, but nerve symptoms improved more slowly and sometimes incompletely.3
Talk to a doctor or pharmacist before taking zinc long term, especially at high doses, and ask about timing if you take other medicines such as antibiotics. Check labels too: many multivitamins and fertility blends already contain zinc.
Common questions
Does zinc make you ejaculate more?
In studies of infertile men, zinc supplementation was associated with higher semen volume, along with better motility and sperm shape.1 Most of these men had lower seminal zinc to start with, and results have varied between studies.
Is zinc good for sperm?
Zinc is essential for sperm production, and it contributes to normal fertility and reproduction. Studies in infertile men have linked supplementation with better sperm motility and a higher share of normally shaped sperm.1
Can you take too much zinc?
Yes. Long-term high doses can lower copper levels, causing anaemia and, in some cases, nerve damage.3 Check with a doctor or pharmacist before taking high-dose zinc.
Read more on this
Zinc and semen volume: does it actually work?
Supplement ingredients for men’s sexual health: what the research shows
How to increase semen volume: what actually works
Sources
- Zhao J, et al. Zinc levels in seminal plasma and their correlation with male infertility: a systematic review and meta-analysis. Sci Rep. 2016;6:22386. PubMed
- Schisterman EF, et al. Effect of folic acid and zinc supplementation in men on semen quality and live birth among couples undergoing infertility treatment: a randomized clinical trial. JAMA. 2020;323(1):35-48. PubMed
- Dutta A, et al. Zinc-induced hematologic toxicities: a systematic review of descriptive studies. Biol Trace Elem Res. 2026;204(9):6628-6642. PubMed
Not medical advice. Written by Eric Stephens from the research cited above; not reviewed by a doctor. If something worries you, see a GP.