Zinc and Testosterone - What 38 Studies Found

The short answer

A 2023 systematic review of 38 studies concluded that zinc deficiency reduces total testosterone and zinc supplementation improves it. The authors found a positive relationship between zinc and testosterone across both human and animal research.

The response was shaped by a person's starting zinc and testosterone levels, the form and elemental amount of zinc, and the duration of supplementation. The increase tended to be greater when people began with zinc deficiency or lower testosterone.

The overall message is clear: adequate zinc matters for normal testosterone, and restoring low zinc status can raise testosterone meaningfully.

What did the review cover?

The researchers searched three scientific databases and identified 2,786 records before selecting 38 relevant studies. Eight were clinical studies in humans and 30 were animal studies.

The evidence covered both sides of the relationship:

• 13 studies examined zinc deficiency;
• 26 studies examined zinc supplementation;

This allowed the authors to look beyond any single experiment. They compared what happened when zinc was restricted, what happened when it was supplied, and which factors appeared to influence the size of the testosterone response.

Zinc deficiency was linked to lower testosterone

The deficiency studies showed a consistent overall direction. In all nine rat studies reviewed, zinc-deficient groups had significantly lower serum testosterone than normal control groups. The two mouse studies also reported lower testosterone with zinc deficiency.

The human dietary studies reached the same general conclusion: restricting zinc reduced serum testosterone in young men.

In one study by Hunt and colleagues, men consuming 1 mg of zinc per day had lower testosterone than men consuming 10 mg per day.

Another study, by Prasad and colleagues, followed four healthy young men during zinc restriction. Their mean total testosterone fell from 39.9 nmol/L at the start to 23.5 nmol/L after eight weeks and 10.6 nmol/L after 20 weeks. This example supports the review's wider finding that lower zinc status can have a substantial effect on testosterone.

Zinc supplementation improved testosterone

The zinc supplementation evidence came from 26 animal and human clinical studies. These studies used different forms of zinc and included several populations, such as healthy older men, men with male sterility, men with sickle cell anaemia, haemodialysis patients and healthy children.

Looking across the animal and clinical research, the review authors concluded that zinc supplementation can help increase testosterone levels. The animal studies also connected zinc supplementation with testicular function, steroid production and recovery of testosterone in models where reproductive function had been impaired.

The healthy-adult study provided a useful human example. Older men with marginal zinc deficiency received 30 mg of elemental zinc per day as zinc gluconate. Mean total testosterone rose from 8.3 nmol/L before supplementation to 14.2 nmol/L after three months, and 16.0 nmol/L after six months. That final value was a 93% increase.

The review found the same pattern in the wider clinical evidence: starting status mattered. A study by Netter and colleagues found that men with lower testosterone before zinc supplementation had larger increases afterwards. Across the review, supplementation tended to produce a greater response in increasing testosterone levels in zinc-deficient people.

What influenced the size of the increase?

The systematic review identified four practical factors that helped explain why the testosterone increase was not identical in every study:

• Starting zinc and testosterone levels: people with lower levels generally had more room to respond.
• Elemental zinc amount: the authors stressed that the amount of elemental zinc matters, not simply the total weight of the zinc compound shown on a label.
• Duration: in the marginally zinc-deficient older men, mean testosterone was higher after six months than after three months.
• Zinc form: different zinc compounds have different bioavailability, which can influence how effectively zinc is absorbed and used.

Together, these findings show how the response can vary in degree. The review found that supplementation improved testosterone, with larger responses tending to occur from a lower starting point and the form, elemental amount and duration helping to shape the result.

Why are zinc and testosterone connected?

The review describes several biological links. Zinc is involved in testosterone production in the testes, including processes inside Leydig cells, which produce testosterone. It also supports enzymes involved in testosterone metabolism and forms part of zinc-finger proteins that help regulate gene activity.

The research also links zinc with androgen-receptor activity, antioxidant defences and proteins involved in steroid production. Together, these mechanisms help explain why testosterone fell during zinc deficiency and improved when low zinc status was restored.

Zinc's role is recognised in European health claims

The research finding aligns with the European Food Safety Authority's scientific opinion. EFSA concluded that a cause-and-effect relationship had been established between dietary zinc and the maintenance of normal serum testosterone concentrations.

The authorised wording in the Great Britain nutrition and health claims register is: "Zinc contributes to the maintenance of normal testosterone levels in the blood."

Conclusion

Across 38 studies, the systematic review found a positive relationship between zinc and total testosterone. Zinc deficiency reduced testosterone, while zinc supplementation improved it. The strongest responses tended to occur when zinc status or testosterone was low at the start.

Individual studies help make that overall finding concrete: testosterone fell during dietary zinc restriction, while marginally zinc-deficient older men experienced a substantial rise after zinc supplementation.

This positive relationship between zinc and testosterone levels is one reason zinc is included in ZMAN+. It is a formula built around ingredients with recognised roles in men’s health.

References

1. Te L, Liu J, Ma J, Wang S. Correlation between serum zinc and testosterone: A systematic review. Journal of Trace Elements in Medicine and Biology. 2023;76:127124. Local full-text copy.
2. Prasad AS, Mantzoros CS, Beck FWJ, Hess JW, Brewer GJ. Zinc status and serum testosterone levels of healthy adults. Nutrition. 1996;12(5):344-348. Local PDF.
3. Hunt CD, Johnson PE, Herbel J, Mullen LK. Effects of dietary zinc depletion on seminal volume and zinc loss, serum testosterone concentrations, and sperm morphology in young men. The American Journal of Clinical Nutrition. 1992;56(1):148-157.
4. Netter A, Hartoma R, Nahoul K. Effect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count. Archives of Andrology. 1981;7(1):69-73.
5. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on zinc-related health claims. EFSA Journal. 2010;8(10):1819. Local PDF.
6. Department of Health and Social Care. Great Britain nutrition and health claims register.

StayPrime supplements were not used in the studies discussed in this article. This article summarises published research and does not claim that taking StayPrime supplements will produce the same results. It is for general information only and is not medical advice. Consult with a doctor if unsure about what you should consume.