Guide
How much zinc should you take a day?
NIH's Office of Dietary Supplements sets the adult zinc RDA at 11 mg/day (men) and 8 mg/day (women), with a 40 mg/day upper limit from all sources — the ceiling exists because higher intakes have been shown to affect copper status.
The adult RDA for zinc is 11 mg a day for men and 8 mg a day for women, counting food and supplements together, according to NIH's Office of Dietary Supplements. The tolerable upper intake level is 40 mg a day from food and supplements combined — so a regular 50 mg/day habit sits above that ceiling, not below it.
Where the numbers come from
NIH's Office of Dietary Supplements sets two different numbers for zinc, and they answer different questions:
| Group | RDA (food + supplements) | UL (all sources) |
|---|---|---|
| Men, 19+ | 11 mg/day | 40 mg/day |
| Women, 19+ | 8 mg/day | 40 mg/day |
The RDA is a target for total intake, food included — most adults get several milligrams from diet before a supplement enters the picture, so a supplement doesn't need to supply the whole 11 or 8 mg on its own. The 40 mg upper limit is a single ceiling for everyone, combining every source: food, water and supplements. Pregnancy and breastfeeding shift the RDA slightly; ask your doctor for a number specific to your situation rather than using the general adult figure.
What the ceiling is actually based on
The 40 mg limit exists because doses above it, taken over weeks, can impair copper status. A 1984 controlled study gave healthy adult men either 50 mg/day of zinc (as two 25 mg doses) or a placebo for six weeks. Plasma copper itself didn't change, but the activity of a copper-dependent enzyme (erythrocyte Cu,Zn-superoxide dismutase) dropped significantly in the zinc group by six weeks — a sign that zinc supplementation was already interfering with copper status at that dose and duration, well below the doses used in short-term cold-lozenge trials. See who should not take zinc for more on this.
Elemental zinc vs. compound weight
A label listing "zinc gluconate 50 mg" is not the same as 50 mg of zinc — gluconate, like every zinc compound, is part zinc and part everything else in the molecule. By molecular weight, roughly:
- Zinc oxide: ~80% elemental zinc
- Zinc citrate: ~34% elemental zinc
- Zinc sulfate: ~23-36% elemental zinc, depending on hydration
- Zinc bisglycinate (chelate): ~31% elemental zinc
- Zinc picolinate: ~21% elemental zinc
- Zinc gluconate: ~14% elemental zinc
US labels are required to state the elemental amount on the Supplement Facts panel (21 CFR 101.9), so the RDA and UL numbers above should be compared against that elemental figure, not the total compound weight printed on the front of the bottle.
What the higher doses in cold research were for
If "how much zinc to take when sick" brought you here: the trials that found a benefit for cold duration used zinc lozenges at 75-207 mg a day, taken only for the several days a cold lasted — far above the 40 mg/day upper limit for ongoing use, and a different question from a daily maintenance dose. Zinc benefits: what the research does and doesn't show covers what those trials actually found, including the side effects that came with that dose.
When the number is different for you
- Kidney disease: zinc is cleared partly by the kidneys, so ask your doctor before adding a zinc supplement if you have kidney disease.
- Pregnancy or breastfeeding: zinc needs shift in pregnancy and lactation, so ask your doctor for a number specific to your situation instead of using a general adult figure.
- Other supplements or medications: a multivitamin, a cold remedy and a dedicated zinc supplement can each contribute toward the 40 mg/day ceiling. See zinc and medications: what to check.
Questions people ask
How much zinc daily should I take?
The adult RDA is 11 mg/day for men and 8 mg/day for women, from food and supplements combined. The 40 mg/day upper limit applies to everyone, from all sources.
Is 50 mg of zinc too much?
Taken regularly, yes — 50 mg/day is above the 40 mg/day upper intake level set for adults, and doses in that range have been shown to affect copper status within weeks.
How much zinc per day for a man? For a woman?
11 mg/day for men, 8 mg/day for women, according to NIH's Office of Dietary Supplements — both from food and supplements combined.
How much is too much zinc?
More than 40 mg/day, from all sources combined, on an ongoing basis. Short-term, high-dose use — like the 75+ mg/day lozenge regimens studied for colds — is a different, doctor-or-label-directed situation, not a standing daily amount.
Can you overdose on zinc?
A single very large dose can cause acute nausea, vomiting and stomach cramping. Chronic daily intake above the 40 mg/day limit is the more common real-world concern, and its main documented effect is on copper status rather than acute poisoning. See zinc side effects.
How much zinc is in cold remedies like lozenges?
It varies by product and form. Check the Supplement Facts panel on whatever product you're considering and compare its elemental zinc amount to the numbers on this page, rather than assuming a specific figure.
How much zinc is in eggs?
About 0.6 mg per large egg, according to USDA FoodData Central — a modest contributor to the RDA compared with red meat, shellfish or a fortified cereal.
Related reading: what is zinc, when is the best time to take zinc, zinc side effects, and how to choose a good zinc.
Sources
- Effect of zinc supplementation on copper status in adult man A 1984 controlled study found 50 mg/day of supplemental zinc for 6 weeks reduced the activity of a copper-dependent enzyme in healthy men, a marker of declining copper status, even though plasma copper itself hadn't changed yet.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.