Zinc: what it does, how much you need, and how much is too much
By Vita · fact-checked against NIH ODS
Vita is Vitaminico's AI nutrition coach. Every number here is checked against the NIH Office of Dietary Supplements; these pages have not yet been reviewed by our registered dietitians.
An essential mineral your body uses for immunity, wound healing, growth, and taste.
Zinc: key facts
- Everyday need (RDA/AI)
- 11 mg for men, 8 mg for women (11 mg in pregnancy, 12 mg in lactation)
- Safe upper limit (UL)
- 40 mg
- Measured in
- mg
- Best foods
- Oysters, beef and other red meat, poultry, crab, beans, nuts, dairy
Adult values from the NIH ODS Zinc fact sheet. Needs differ in pregnancy, lactation and childhood.
What does zinc do?
Zinc helps run about 100 enzymes and is needed to build proteins and DNA, which makes it central to normal growth, wound healing, and a working immune system. Your body also relies on it for a proper sense of taste and smell. Because you have no dedicated way to store zinc, you need a small amount from food every day to stay topped up.
Why you might be low on zinc
- Digestive diseases like Crohn's or ulcerative colitis, or gut/bariatric surgery, which reduce how much zinc you absorb
- Vegetarian or vegan diets, since phytates in beans and grains block zinc absorption (vegetarians may need up to 50% more)
- Pregnancy or breastfeeding, which raise zinc requirements and can deplete stores
- Heavy or long-term alcohol use, which lowers absorption and increases zinc lost in urine
- Being an older adult, as intakes are often marginal, or an exclusively breastfed infant over 6 months of age
Signs of low zinc
These are common signals, not a diagnosis — a blood test and your clinician confirm a real gap.
- Loss of, or changes in, the sense of taste and smell
- Poor appetite
- Slowed growth in infants and children
- Hair loss
- Frequent infections and weaker immunity
- Diarrhea and slow wound healing
Best food sources of zinc
| Food | Typical amount |
|---|---|
| Oysters (Eastern, farmed, raw) | 32 mg per 3 oz |
| Beef (bottom sirloin, roasted) | 3.8 mg per 3 oz |
| Blue crab, cooked | 3.2 mg per 3 oz |
| Fortified breakfast cereal (25% DV) | 2.8 mg per serving |
| Pumpkin seeds, roasted | 2.2 mg per 1 oz |
| Pork chop (center loin, broiled) | 1.9 mg per 3 oz |
| Lentils, boiled | 1.3 mg per 1/2 cup |
How much zinc is too much?
The tolerable upper intake level (UL) for adults is 40 mg per day. Chronic intakes above 40 mg can impair copper absorption and lower immune function; deficiency slows growth and weakens immunity.
For adults the safe upper limit from food and supplements combined is 40 mg a day, and regularly exceeding it can cause nausea, vomiting, cramps, and headaches. Chronic high doses (often 150 mg or more) can block copper absorption, lower "good" HDL cholesterol, weaken immunity, and cause nerve problems; zinc nasal sprays and gels should be avoided because they have caused permanent loss of smell.
Stacking a multivitamin, a single supplement and fortified foods adds up faster than it looks — run your full dose through the free Supplement Safety Checker before adding anything new.
Zinc FAQ
Do zinc lozenges actually help with a cold?
They might. A Cochrane review found zinc lozenges or syrup taken within 24 hours of the first symptoms can shorten a cold in otherwise healthy people, but the ideal dose and form aren't settled and results are mixed. Skip zinc nasal sprays and gels, which have been linked to lasting loss of smell.
Should vegetarians and vegans take extra zinc?
Possibly. Plant foods contain phytates that bind zinc, so vegetarians may need up to 50% more than the RDA. Soaking or sprouting beans, grains, and seeds and choosing leavened breads improves how much zinc you actually absorb.
Can zinc interfere with my medications?
Yes. Zinc can reduce the absorption of quinolone and tetracycline antibiotics and of penicillamine, so take zinc at least 2 hours before or 4-6 hours after them. Thiazide diuretics also increase zinc lost in urine, so check with your provider if you take them long term.
Source
Every RDA/AI, upper limit and unit on this page is drawn from the NIH Office of Dietary Supplements Zinc fact sheet ›.
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Educational, not medical advice. The upper limits shown are Tolerable Upper Intake Levels for healthy adults from all sources combined; needs differ in pregnancy, lactation, childhood and with some conditions or medications. This page does not diagnose a deficiency or set your dose — talk to your clinician before starting any high-dose supplement.