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Trace mineral

Zinc

Immune function, wound healing, DNA synthesis, taste/smell, growth, enzyme function

Essential nutrient

Reference intakes (RDA or AI) are set by the National Academies of Sciences, Engineering, and Medicine. Deficiency thresholds come from clinical and WHO guidance.

At a glance

Women, 19-50

8 mg (11 mg pregnancy, 12 mg lactation)

Men, 19-50

11 mg

Upper limit (adults)

40 mg/day

How common is deficiency?

COMMON globally (about 1 in 6 people); overt deficiency uncommon in the US but marginal intake is seen in vegetarians and older adults

Food sources

Animal sources

Oysters (highest), beef, crab, lobster, pork, dark-meat poultry, dairy

Plant sources

Pumpkin seeds, chickpeas, lentils, cashews, hemp seeds, oats, fortified cereals (phytates reduce absorption)

Deficiency and testing

Signs of deficiency

Frequent infections, slow wound healing, hair loss, loss of taste/smell, diarrhea, skin lesions (acrodermatitis), poor appetite, growth failure in children, hypogonadism

Who is at higher risk

Vegetarians/vegans, older adults, GI disease (Crohn's, celiac), alcohol use disorder, bariatric surgery, sickle cell disease, pregnancy/lactation

How it is tested

Plasma or serum zinc (trace-element-free tube; fasting, morning); alkaline phosphatase (zinc enzyme); hair/urine zinc (not reliable)

Cut-offs

Fasting morning serum zinc <70 mcg/dL (women) or <74 mcg/dL (men) suggests deficiency (IZiNCG); falls with infection/inflammation

Symptoms are not specific. Only a clinician with the right tests can tell whether you are deficient.

Supplement forms

Common forms

zinc gluconate, citrate, acetate, picolinate, bisglycinate (glycinate), sulfate, oxide, lozenges.

More effective

zinc citrate, gluconate, acetate, picolinate, and bisglycinate are all well absorbed; take with food if it upsets the stomach (food slightly lowers absorption); acetate or gluconate lozenges are the forms tested for colds, started early at about 75 mg/day elemental zinc for under a week.

Less effective

zinc oxide taken orally (lower absorption); taking with high-phytate foods, iron, or calcium at the same time; more than 40 mg/day long term (copper deficiency, anemia); intranasal zinc (reports of loss of smell).

Safety, interactions and halal notes

Safety and interactions

Upper limit for adults: 40 mg/day. Going above the upper limit over time can cause harm, so check labels and talk to a clinician before high-dose supplements.

Halal note

The nutrient itself is not a halal question. For supplements, check the delivery form: gelatin (pork or non-halal bovine), capsule shells, glycerin, and alcohol-based carriers need halal certification. Ask for the halal certificate, not just a label claim. This is general guidance, not a certification.

Frequently asked questions

How much Zinc do adults need per day?

Women 19-50: 8 mg (11 mg pregnancy, 12 mg lactation). Men 19-50: 11 mg. Upper limit: 40 mg/day. Needs change with age, pregnancy and health conditions.

What are the signs of Zinc deficiency?

Frequent infections, slow wound healing, hair loss, loss of taste/smell, diarrhea, skin lesions (acrodermatitis), poor appetite, growth failure in children, hypogonadism. These signs are not specific, so only a clinician with the right tests can confirm a deficiency.

What are the best food sources of Zinc?

Animal sources: Oysters (highest), beef, crab, lobster, pork, dark-meat poultry, dairy. Plant sources: Pumpkin seeds, chickpeas, lentils, cashews, hemp seeds, oats, fortified cereals (phytates reduce absorption).

Which form of Zinc supplement is best?

Sources

NIH Office of Dietary Supplements fact sheet

← Back to the full nutrient guide

This page is for education only and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Supplements are not intended to diagnose, treat, cure or prevent any disease. Talk to a qualified clinician before starting a supplement, especially if you are pregnant, breastfeeding, take medicine or have a medical condition. Daily needs are US reference intakes for adults 19-50.

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