Zinc is a type of metal that is known as an essential trace element because the body requires very< small amounts of it for health purposes.
Zinc is present in many cells throughout the body, and is vital to the functioning of over 300 unique enzymes. Zinc also has a hand in many processes that are key to bodily function, including the production of protein and DNA, thyroid health maintenance and blood clotting.
The nutrient is vital to proper growth and development, starting in the womb through childhood. Zinc supplements are used mainly for the treatment and prevention of zinc deficiency and diarrhea in children. It is also helpful in the treatment of gastric ulcers.
Uses and effectiveness
Zinc is used for:
- Boosting immunity: Zinc gluconate may help. (More studies are needed.)
- Sensory perception: Taste, vision and smell. (Possibly effective. More studies needed.)
- Acne vulgaris (Research is mixed. More studies are needed.)
- Dementia/Alzheimer's disease (Zinc supplementation didn't seem to help. More studies are needed.)
- Attention-deficit hyperactivity disorder (ADHD): May help in older children. (More studies are needed.)
- Sickle cell anemia control: May help with manage and reduce symptom.
- Ringing in the ears (Results are mixed. More research is needed.)
- Infertility (More research is needed.)
- Osteoporosis: Zinc supplementation, along with copper, manganese, and calcium, might help reduce bone loss in postmenopausal women.
- Wilson's disease: Inability to excrete copper. Zinc may help manage the disease. (More studies are needed.)
- Herpes 1 & 2: May be an effective treatment option. (More research is needed.)
- Athletic performance and strength enhancement: May help athletes who are low in zinc or have zinc deficiency. (More studies are needed.)
- Diabetes: Zinc supplementation may help raise zinc levels and improve glycemic control. (More studies are needed.)
- Common cold prevention (nostril spray). (Research is mixed. More studies are needed.)
Zinc sulfate is used in eye drops to help soothe irritated eyes. Zinc citrate can be found in toothpaste and mouthwash to help prevent plaque and gingivitis.
DeficiencyWorldwide, 4% of disease and death in children is attributed to zinc deficiency.
Although zinc deficiency is common in other countries, it is not a problem in the United States. Moderate zince deficiency can stunt growth, delay sexual development, cause impotence in males, acute diarrhea in children, and slow wound healing.
Digestive disorders, gastrointestinal surgery, vegetarianism, being breastfed as an older infant, alcoholism, and sickle cell disease can lead to zinc deficiency. The reason older breastfed infants are at risk for zinc deficiency is because breast milk provides sufficient amounts of the mineral for infants for six months.[2, 9]
Symptoms of deficiency
- Slow growth
- Reduced insulin levels
- No appetite
- Rough, dry skin
- Trouble with wound healing
- Hair loss
- Weight loss
- Reduced sense of taste and smell
- Eye and skin sores
- Impaired vision
Treating zinc deficiency
Difficulty absorbing zinc can be a factor in developing zinc deficiency. Influences on absorption include how much zinc you take in and dietary phytate levels. Dietary phytate affects zinc bio-availability.
Zinc supplementation or eating foods high in zinc can help treat and prevent deficiency. Most multivitamin contain zinc. It's also available on its own. Homeopathic remedies for colds may also contain zinc.
Getting too much zinc can reduce copper levels, compromise your immune system and lead to lower LDL, "good," cholesterol levels.
- Stomach cramps
- No appetite
Adding more zinc-rich foods to your diet can help increase zinc levels. Sources include:
- Red meat
- Fortified breakfast cereals
- Dairy products
- Whole grains
Worldwide, 4% of disease and death in children is attributed to zinc deficiency.
Upper limits of zinc are:
- 4mg (birth to 6 months)
- 5mg (Infants 7 to 12 months)
- 7mg (Children 1 to 3 years)
- 12mg (Children 4 to 8 years)
- 23mg (Children 9 to 13 years)
- 34mg (Teens 14 to 18 years)
- 40mg (Adults)
Do not take zinc in doses higher than indicated here without doctor's supervision.
Diarrhea in Children
Acute diarrhea is the number-one cause of death in children in developing countries. Giving children zinc supplements, coupled with oral rehydration solutions, may help provide relief. It can cut episodes short and reduce the frequency and intensity of gastrointestinal problems for about three months. The recommended zinc dose for acute diarrhea in infants younger than 6 months old is 10mg a day for 10 to 14 days. For children age 6 months to 5 years, it's 20mg a day for the same duration.[5, 8]
Zinc can improve healing time in gastric ulcer patients. In one study, rats on a zinc-deficient diet took longer to heal from an ulcer compared to rats in a control group. Zinc supplementation did not improve healing time, but it did heighten levels of the mineral in the blood. According to researchers from Osaka City University Medical School in Japan,zinc is effective for gastric ulcers, but it's imperative that treatment begin early.
Safety and side effects
- Zinc is well tolerated and safe when taken in recommended doses.
- There are few side effects associated with zinc intake, but it may cause vomiting, nausea, or diarrhea.
- Since cadmium and zinc are typically found together in nature, supplements containing zinc may also contain cadmium. Long-term exposure to high doses of cadmium can cause kidney disease. If you have concerns about the level of cadmium in zinc supplements, choose zinc gluconate since it doesn't have as much cadmium.
- Reduced immune responses may occur with zinc usage.
- Avoid taking high doses of zinc. It could cause liver failure, intestinal bleeding and other serious problems.
- Taking more than 100mg of supplemental zinc per day can substantially increase prostate cancer risk.
- Patients with heart disease, high cholesterol/blood fats, skin disorders, gastrointestinal disorders, liver disease, blood disorders, neurological disorders, kidney disease, and other chronic health problems, should discuss the possible dangers of taking zinc ahead of time.
- Taking zinc supplements for 10 years or longer doubles prostate cancer risk.
- Taking a multivitamin along with a separate zinc supplement increases your chances of dying from prostate cancer.
- Zinc may increase bleeding risk. Do not take it if you have a bleeding disorder.
- Blood iron problems can result from taking 450mg or higher of zinc daily.
- Death can result from taking 10g to 30g of zinc in one dose.
- Zinc nose sprays may impair your sense of smell and zinc nasal gels may cause tingling or burning.
- Zinc may cause respiratory infections in children.
- Topical zinc may cause skin irritation.
- It's OK for pregnant and breastfeeding women to take zinc in normal, recommended doses. If you're over 18, don't take more than 40mg daily. Don't take more than 34mg if you are 14 to 18 years old.
- Zinc could reduce blood sugar levels. If you are diabetic or hypoglycemic, have your blood sugar monitored regularly.
- Check with your doctor if you have symptoms of zinc deficiency. It could be something else. Don't self-treat with supplements.
- Do not use excessive amounts of denture adhesive creams as they contain zinc, and overdosing on them can lead to copper deficiency.
- Zinc oxide may cause an allergic reaction. Do not take it if you have a zinc allergy.
Zinc may interact with medications, supplements, herbs, and even certain types of foods.
- Penicillamine: Zinc may decrease the effectiveness. Take at least two hours apart.
- Antibiotics: Zinc may decrease absorption of these medications. Take antibiotics at least two hours before, or four to six hours after zinc supplementation.
- Cisplatin: Zinc may reduce the effectiveness of EDTA (A medication taken for lead poisoning).
- Amiloride: This medication can cause zinc overload in the body.
- Calcium: Calcium can reduce zinc absorption.
- Copper: Zinc overload can reduce copper absorption.
- Iron: Zinc and iron can hinder each other's absorption.
- Coffee: Taking zinc sulfate with black coffee can interfere with absorption.
- Fiber: Fiber may interfere with zinc absorption. Over time, the body may be able to compensate.
- Dairy products and calcium-fortified foods: Calcium can interfere with zinc absorption. The body may be able to compensate for this over time.
- Phytate: This is a molecule found in grains, legumes, seeds, and soy. It can interfere with zinc absorption. However, the body may be able to adapt over time.
- Protein: Zinc attaches to proteins and is absorbed during digestion. The amount of zinc absorbed depends on the type of protein. For example, animal protein boosts zinc absorption while soy protein hinders it.
Note: This is not a complete list. Talk to your doctor if you have questions about how zinc intake will interfere with any medications or supplements you're already taking.
Recommended zinc dosage
Daily Dosage Recommendation
0 to 6 months old
Babies 7 to 12 months old
Children 1 to 3 years old
Children 4 to 8 years old
Children 9 to 13 years old
Teens 14 to 18 years old (girls)
Teens 14 to 18 years old (boys)
Adult women (pregnant)
Adult women (breastfeeding)
Based on table appearing in 
Dosages for specific conditions
- Common cold: 9mg to 24mg of elemental zinc in a lozenge (zinc gluconate or acetate) by mouth every two hours.
- Diarrhea in malnourished or zinc-deficient children: 10mg to 40mg elemental zinc daily.
- Stomach ulcer: 200mg of zinc sulfate three times daily.
- Osteoporosis: Take a combination of 15mg zinc, 5mg manganese, 2.5mg copper, and 1000mg calcium.
- Acne: 30mg to 135mg elemental zinc daily.
- Zinc deficiency: Dosages vary depending on the extent of deficiency.
Note that this list is not thorough. If you have a specific condition that is not noted here, contact your doctor for recommended dosage.
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- Mayo Clinic; "Zinc"
- MedlinePlus: "Zinc"
- Marianna K. Baum, et. al.; Clinical Infectious Diseases; "Randomized, Controlled Clinical Trial of Zinc Supplementation to Prevent Immunological Failure in HIV-Infected Adults;" 2010
- Fashner J., et. al.; American Family Physician; "Treatment of the Common Cold in Children and Adults;" 2012
- Penny ME; Annals of Nutrition & Metabolism; "Zinc Supplementation in Public Health" 2013
- Krebs NF.; Annals of Nutrition & Metabolism; "Update in Zinc Deficiency and Excess in Clinical Pediatric Practice;" Krebs, NF; Annals of Nutrition & Metabolism;" 2013
- Watanabe T, et. al.; Digestive Diseases and Sciences; "Zinc Deficiency Delays Gastric Ulcer Healing in Rats;" Watanabe T, et.al; Digestive Diseases and Sciences;" 1995
- Chaitali Bajait, Vijay Thawani; INdian Journal of Pharmacology; "Role of Zinc in Pediatric Diarrhea;" Chaitali Bajait and Vijay Thawani;" 2011
- NIH Office of Dietary Supplements; "Zinc: Quick Facts;"