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Trusted Health Reviews editors · October 2026
Zinc and Testosterone: How Closely Are They Linked?
Normal testosterone production needs zinc, and a deficiency can bring it down. We look at the research, who is likely to run low, sensible doses and the upper limit.
In briefChecked October 2026
A deficiency of zinc is tied to low testosterone, and the mineral is essential to normal male reproductive health. The men who seem to gain from supplements are mainly those who are truly low in zinc. Studies in men with adequate zinc, among them an independent trial of the popular ZMA formula, found no rise. Most US adults get enough from food, and the adult upper limit is 40 mg a day from all sources.
The Role of Zinc
Hundreds of enzymes depend on zinc, and so does normal function of the testes, sperm production included. Low zinc goes along with low testosterone, which explains why so many testosterone formulas include it.
What Happens When Zinc Runs Low
Prasad et al. (1996) published a small study in Nutrition. Young men on a zinc-restricted diet saw their testosterone drop markedly, while older men who were marginally zinc deficient had higher testosterone after taking zinc. Normal zinc levels change the picture. Koehler et al. (2009) ran an independent study of ZMA (zinc, magnesium and vitamin B6) in 14 healthy exercising men and found no change in total or free testosterone.
Food gives most US adults enough zinc. You're more likely to be low if you have a digestive condition that interferes with absorption (Crohn's disease, for example), drink heavily, or follow a vegetarian or vegan diet, because phytates in grains and legumes cut zinc absorption. Zinc blood tests exist but aren't very precise, so bring up any concern with your doctor.
It may, in men who are deficient. In a small study, older men with marginal zinc deficiency had higher testosterone after taking zinc. Studies in men with adequate zinc, including an independent ZMA trial, found little or no effect.
Adult men should aim for 11 mg a day. The upper limit is 40 mg a day counting every source, including food and multivitamins, and taking 50 mg or more for long periods can cause copper deficiency. Per serving, TestRX lists 10 mg of zinc. Testosil lists 40 mg, which hits the upper limit by itself.
ZMA is a blend of zinc (as monomethionine aspartate), magnesium aspartate and vitamin B6. Higher testosterone was reported in a small 2000 study of college football players. An independent 2009 study of healthy exercising men found no change in total or free testosterone.
Food supplies enough for most people. Digestive conditions that affect absorption, heavy drinking, and vegetarian or vegan diets raise the risk. Bring up any concern with your doctor.
Oysters top the list, followed by red meat, poultry, pumpkin seeds, legumes and nuts. Animal foods generally give zinc that's better absorbed than zinc from plant foods.
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