Zinc
Preliminary· human dataEssential mineral where correcting a shortfall helps — but more isn't better.
What it is
Zinc is an essential mineral involved in immunity, hormone production and many enzymes. As with most minerals, correcting a genuine shortfall helps — but more is not better.
What the evidence shows
Testosterone. Preliminary· human data Zinc's role here is mainly about correcting a deficiency. In men who are genuinely low, restoring it can help hormone levels; in men who already have enough, extra zinc does not reliably raise testosterone despite the marketing.
Colds. Preliminary· human data There is reasonable evidence that zinc taken promptly at the onset of a cold may shorten it slightly, though results vary by form and dose.
Who it suits
People with a likely or tested shortfall — some athletes, and those with limited dietary sources. Meat, shellfish, seeds and legumes cover most people's needs.
Practical notes
Chronic high doses cause a copper deficiency, which can lead to anaemia and nerve problems, so don't take a lot long-term without a reason. Large single doses on an empty stomach commonly cause nausea.
Sources
Frequently asked questions
- Does zinc boost testosterone?
- Mainly by correcting a deficiency. In men who are genuinely low in zinc, restoring it can help hormone levels; in men who already have enough, extra zinc does not reliably raise testosterone despite the marketing.
- Does it help with colds?
- There's reasonable evidence that zinc taken promptly at the onset of a cold may shorten it slightly, though results vary by form and dose. That's separate from any performance claim.
- Can I take too much?
- Yes. High-dose zinc over time causes copper deficiency, so more is not better. Food sources — meat, shellfish, seeds and legumes — cover most people's needs.
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Written and reviewed by Mathew Beale — MSc Biotechnology, University of Reading.
Last reviewed: