- What other names is Zinc known by?
- What is Zinc?
- How does Zinc work?
- Are there safety concerns?
- Are there any interactions with medications?
- Dosing considerations for Zinc.
Zinc Safety and Side Effects
Zinc is safe for most adults when applied to the skin, or when taken by mouth in amounts not larger than 40 mg per day for adults age 19 and older. Routine zinc supplementation is not recommended without the advice of a healthcare professional. In some people zinc might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage, and other side effects. Using zinc on broken skin may cause burning, stinging, itching, and tingling.
High doses above the recommended amounts might cause fever, coughing, stomach pain, fatigue, and many other problems.
Taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer. There is also concern that taking large amounts of a multivitamin plus a separate zinc supplement increases the chance of dying from prostate cancer.
Taking 450 mg or more of zinc daily can cause problems with blood iron. Single doses of 10-30 grams of zinc can be fatal...
Zinc is taken by mouth for the treatment and prevention of zinc deficiency and its consequences, including stunted growth and acute diarrhea in children, slow wound healing, and Wilson's disease.
It is also used for boosting the immune system, improving growth and heath in zinc deficient infants and children, for treating the common cold and recurrent ear infections, the flu, upper respiratory tract infections, preventing and treating lower respiratory infections, swine flu, ringing in the ears, and severe head injuries. It is also used for malaria and other diseases caused by parasites.
Some people use zinc for an eye disease called macular degeneration, for night blindness, and for cataracts. It is also used for asthma; diabetes and associated nerve damage; high blood pressure; AIDS/HIV, AIDS/HIV-related pregnancy complications; HIV-related diarrhea and AIDS diarrhea-wasting syndrome, AIDS-related infections, and high levels of bilirubin in blood (hyperbilirubinemia).
It is also taken by mouth anorexia nervosa, obsessive-compulsive disorder, depression, dementia, dry mouth, attention deficit-hyperactivity disorder (ADHD), blunted sense of taste (hypogeusia), hepatic encephalopathy, alcohol-related liver disease, Crohn's disease, ulcerative colitis, inflammatory bowel disease, canker sores, stomach ulcers, leg ulcers, and bed sores.
Some men take zinc by mouth for male fertility problems and enlarged prostate, as well as erectile dysfunction (ED).
Zinc is taken by mouth for osteoporosis, rheumatoid arthritis, psoriatic arthritis, warts, and muscle cramps in people with liver disease. It is also used for sickle cell disease, itching, rosacea, hair loss, psoriasis, eczema, acne, a blood disorder called thalassemia, Alzheimer's disease, Down syndrome, Hansen's disease, and cystic fibrosis.
It is also taken by mouth for cancer prevention, including esophageal cancer, colon and rectal cancer, stomach cancer, brain cancer, head and neck cancer recurrence, nasal and throat cancer recurrence, and non-Hodgkin's lymphoma. Zinc is used by mouth to prevent inflammation in the lining of the digestive tract, chemotherapy-related complications, anemia, pregnancy-related complications including iron deficiency, vitamin A deficiency (taken with vitamin A), arsenic poisoning, chronic obstructive pulmonary disease (COPD), clogged arteries, leukemia, burns, diaper rash, leprosy, and skin lesions caused by leishmania infection.
Some athletes use zinc by mouth for improving athletic performance and strength.
Zinc is also applied to the skin for treating acne, foot ulcers caused by diabetes, leg ulcers, diaper rash, warts, aging skin, brown patches on the face, herpes simplex infections, parasitic infections, and to speed wound healing. Zinc is also applied to the anus for people with problems controlling bowel movements.
Zinc citrate is used in toothpaste and mouthwash to prevent dental plaque formation and gingivitis. Zinc is also used in chew gum, candies, and mouth rinses to treat bad breath.
There is a zinc preparation that can be sprayed in the nostrils for treating the common cold.
Zinc sulfate is used in eye drop solutions to treat eye irritation.
Zinc is injected into the vein to improve nutrition in people recovering from burns.
Note that many zinc products also contain another metal called cadmium. This is because zinc and cadmium are chemically similar and often occur together in nature. Exposure to high levels of cadmium over a long time can lead to kidney failure. The concentration of cadmium in zinc-containing supplements can vary as much as 37-fold. Look for zinc-gluconate products. Zinc gluconate consistently contains the lowest cadmium levels.
- Zinc deficiency. Zinc deficiency might occur in people with severe diarrhea, conditions that make it hard for the bowel to absorb food, liver cirrhosis, and alcoholism. It may also occur after major surgery and during long-term use of tube feeding in the hospital. Taking zinc by mouth or giving zinc intravenously (by IV) helps to restore zinc levels in people who are zinc deficient. However, taking zinc supplements regularly is not recommended.
Likely Effective for...
- Diarrhea. Taking zinc by mouth reduces the duration and severity of diarrhea in children who are undernourished or zinc deficient. Severe zinc deficiency in children is common in developing countries. Also giving zinc to undernourished women during pregnancy and continuteing until one month postpartum reduces the incidence of diarrhea in infants during the first year of life.
- An inherited disorder called Wilson's disease. Taking zinc by mouth improves symptoms of an inherited disorder called Wilson's disease. People with Wilson's disease have too much copper in their bodies. Zinc blocks how much copper is absorbed and increases how much copper the body releases.
Possibly Effective for...
- Acne. Research suggests that people with acne have lower blood and skin levels of zinc. Taking zinc by mouth appears to help treat acne. However, it's unclear how beneficial zinc is compared to acne medications such as tetracycline or minocycline. Applying zinc to the skin in an ointment does not seem to help treat acne unless used in combination with the antibiotic drug called erythromycin.
- An inherited disorder that affects zinc uptake (acrodermatitis enteropathica). Taking zinc by mouth seems to help improve symptoms of acrodermatitis enteropathica.
- Age-related vision loss (age-related macular degeneration). People who consume more zinc as part of their diet seem to have a lower risk of developing age-related vision loss. Research shows that taking supplements containing zinc and antioxidant vitamins may modestly slow vision loss and prevent age-related vision loss from becoming advanced in people at high risk. It's still not clear if taking zinc along with antioxidant vitamins helps prevent age-related vision loss from becoming advanced in people at low risk. Most research shows that taking zinc alone, without antioxidant vitamins, does not help most people with age-related vision loss. However, it's possible that people with certain genes that make them susceptible to age-related vision loss might benefit from zinc supplements.
- Anorexia. Taking zinc supplements by mouth might help increase weight gain and improve depression symptoms in teens and adults with anorexia.
- Attention deficit-hyperactivity disorder (ADHD). Taking zinc by mouth in combination with conventional treatment might slightly improve hyperactivity, impulsiveness, and socialization problems in some children with ADHD. However, zinc does not seem to improve attention span. Some research suggests that children with ADHD have lower zinc levels in their blood than children without ADHD. Other research suggests people with ADHD with lower zinc levels might not respond well enough to prescription medications for ADHD (stimulants). Studies using zinc for ADHD have taken place in the Middle East where zinc deficiency is relatively common compared to Western countries. It is not known if zinc would have the same potential benefits when used for ADHD in people from Western countries.
- Burns. Giving zinc intravenously (by IV) together with other minerals seems to improve wound healing in people with burns. However, taking zinc alone does not appear to improve wound healing in all people with burns, but it might reduce recovery time in people with severe burns.
- Tumors in the rectum and colon. Research suggests that taking a supplement containing selenium, zinc, vitamin A 2, vitamin C, and vitamin E by mouth daily for 5 years reduces the risk of recurrent large-bowel tumors by about 40%.
- Common cold. Although some conflicting results exist, most research shows that taking lozenges containing zinc gluconate or zinc acetate by mouth helps reduce the duration of a cold in adults. However, side effects such as bad taste and nausea might limit its usefulness. It is unclear if zinc helps prevent common colds. In adults, taking zinc supplements by mouth does not seem to prevent common colds. However, zinc gluconate lozenges might help prevent colds in children and adolescents. Using zinc as a nose spray does not seem to help prevent colds.
- Depression. Population research suggests that zinc levels are lower in people with depression. Some research suggests that taking zinc along with antidepressants improves depression in people with major depression. However, other research shows that it improves depression in only people who do not respond to treatment with antidepressants alone. It doesn't seem to improve depression in people who respond to antidepressant treatment.
- Foot ulcers due to diabetes. Research suggests that applying zinc hyaluronate gel can help foot ulcers heal faster than conventional treatment in people with diabetes.
- Diaper rash. Giving zinc gluconate by mouth to infants seems to speed up the healing of diaper rash. Applying zinc oxide paste also seems to improve the healing of diaper rash. However, it doesn't seem to work as well as applying 2% eosin solution.
- Gingivitis. Using toothpastes containing zinc, with or without an antibacterial agent, appears to prevent plaque and gingivitis. Some evidence also shows that zinc-containing toothpaste can reduce existing plaque. However, other conventional treatments may be more effective. Also, most studies that showed benefit used zinc citrate in combination with triclosan, which is not available in the US.
- Bad breath. Research suggests that chewing gum, sucking on a candy, or using a mouth rinse containing zinc reduces bad breath.
- Herpes simplex virus. Applying zinc sulfate or zinc oxide to the skin, alone or with other ingredients, seems to reduce the duration and severity of oral and genital herpes. However, zinc might not be beneficial for recurrent herpes infections.
- Taste disorder (hypogeusia). Some early research suggests that taking zinc by mouth does not improve taste disorders in children with zinc deficiency. But most evidence suggests that taking zinc by mouth is effective for people with a reduced ability to taste foods due to zinc deficiency or some other conditions.
- Skin lesions (Leishmania lesions). Research suggests that taking zinc sulfate by mouth or injecting as a solution into lesions helps heal lesions in people with Leishmaniasis. However, injecting zinc solutions into lesions does not seem to be more effective than conventional treatments.
- Leprosy. Taking zinc by mouth in combination with anti-leprosy drugs seems to help treat leprosy.
- Muscle cramps. Taking zinc by mouth seems to help treat muscle cramps in people with cirrhosis and zinc deficiency.
- Weak bones (osteoporosis). Low zinc intake seems to be linked to lower bone mass. Taking a zinc supplement in combination with copper, manganese, and calcium might decrease bone loss in women who have passed menopause.
- Peptic ulcers. Taking zinc acexamate by mouth seems to help treat and prevent peptic ulcers. However, this form of zinc is not available in the US.
- Pneumonia. Most research suggests that taking zinc might help PREVENT pneumonia in undernourished children. However, research assessing the effects of zinc for TREATING pneumonia once it develops shows conflicting.
- Complications during pregnancy. Taking zinc by mouth during pregnancy appears to reduce the risk for early delivery by 14%. However, zinc supplementation does not seem to reduce the risk for stillbirths or infant deaths. Taking zinc with vitamin A might help restore night vision in pregnant women affected by night blindness. However, taking zinc alone does not appear to have this effect.
- Bed sores. Applying zinc paste appears to help improve the healing of bed sores in elderly people. Also, increasing zinc intake in the diet seems to improve bed sore healing in hospitalized patients with bed sore.
- Food poisoning (shigellosis). Research shows that taking a multivitamin syrup containing zinc along with conventional treatment can improve recovery time and reduce diarrhea in undernourished children with food poisoning.
- Sickle cell disease. Taking zinc by mouth seems to help reduce symptoms of sickle cell disease in people with zinc deficiency. Taking zinc supplements also appears to decrease the risk for complications and infections related to sickle cell disease.
- Leg ulcers. Taking zinc sulfate by mouth appears to help some types of leg ulcers heal faster. The effects seem to be greater in people with low levels of zinc before treatment. Applying zinc paste to leg ulcers also appears to improve healing.
- Vitamin A deficiency. Taking zinc by mouth together with vitamin A seems to improve vitamin A levels in undernourished children better than vitamin A or zinc alone.
- Warts. Early research suggests that applying a zinc sulfate solution improves plane warts but not common warts. Applying zinc oxide ointment appears to be as effective as conventional treatments for curing warts. Taking zinc sulfate by mouth also appears to be effective.
Possibly Ineffective for...
- AIDS diarrhea-wasting syndrome. Taking zinc by mouth together with vitamins does not seem to improve AIDS diarrhea-wasting syndrome.
- Hair loss. Although there is early evidence that suggests taking zinc together with biotin might be helpful for hair loss, most studies suggest that zinc is not effective for this condition.
- Scaly, itchy skin (eczema). Taking zinc by mouth does not appear to improve skin redness or itching in children with eczema.
- Cataracts. Taking zinc by mouth together with antioxidant vitamins does not seem to help treat or prevent cataracts.
- Cystic fibrosis. Zinc sulfate does not appear to improve lung function in children or adolescents with cystic fibrosis, although it may reduce the need for antibiotics.
- HIV/AIDS. Taking zinc by mouth along with antiretroviral therapy does not improve immune function or reduce the risk of death in adults or children with HIV.
- Pregnancy complications in women with HIV/AIDS. Taking zinc by mouth during pregnancy does not appear to reduce the risk of transmitting HIV to the infant. Also, zinc does not appear to prevent infant death or maternal wasting in pregnant women with HIV.
- Infant development. Giving zinc to infants does not improve mental or motor development.
- Inflammatory bowel disease (IBD). Taking zinc by mouth does not seem to help treat IBD.
- Flu. Taking zinc supplements by mouth is unlikely to improve immune function against the flu virus in people who are not at risk for zinc deficiency.
- Ear infection. Taking zinc does not appear to prevent ear infections in children.
- Iron-deficiency during pregnancy. Taking zinc by mouth does not seem to help improve iron levels in women taking iron and folic acid supplements.
- Prostate cancer. Early research suggests that taking zinc along with other vitamins and minerals may prevent prostate cancer in some men. However, other research shows that taking zinc can increase the risk of developing prostate cancer and increase the risk of dying from prostate cancer.
- Red and irritated skin (psoriasis). Taking zinc by mouth does not seem to help treat psoriasis.
- Joint inflammation associated with a specific skin condition (psoriatic arthritis). Taking zinc by mouth, alone or together with painkillers, has no effect on the progression of psoriatic arthritis.
- Joint inflammation (rheumatoid arthritis). Taking zinc by mouth does not seem to help treat rheumatoid arthritis.
- Rosacea. Research suggests that taking zinc by mouth daily for 90 days does not improve quality of life or symptoms associated with rosacea.
- Sexual dysfunction. Research suggests that zinc supplementation does not improve sexual function in men with sexual dysfunction related to kidney disease.
- Ringing in the ears (tinnitus). Taking zinc by mouth does not seem to help treating ringing in the ears.
- Upper respiratory tract infections. Taking zinc by mouth does not decrease the risk for upper respiratory tract infections.
Likely Ineffective for...
- Malaria. Taking zinc by mouth does not help prevent or treat malaria in undernourished children in developing countries. But some research suggests it might reduce the risk for high fevers in children with malaria.
Insufficient Evidence to Rate Effectiveness for...
- AIDS-related infections due to weakened immunity. There is some early evidence that taking zinc supplements by mouth in combination with the drug zidovudine might reduce infections that occur because of a weakened immune system. However, it might negatively affect survival in people with AIDS.
- Alcohol-related liver disease. Taking zinc sulfate by mouth might improve liver function in people with alcohol-related liver disease.
- Alzheimer's disease. Some early research shows that zinc supplements might slow the worsening of symptoms in people with Alzheimer's disease.
- Anemia. Research suggests that giving a porridge containing zinc and other vitamins and minerals to infants reduces the risk of anemia.
- Arsenic poisoning. Early research suggests that taking zinc together with spirulina can reduce symptoms and arsenic levels in the urine and hair of people with long-term arsenic poisoning.
- Asthma. Zinc intake does not appear to be linked to the risk for developing asthma in children.
- A blood disorder called beta-thalassemia. Early research suggests that taking zinc sulfate while undergoing blood transfusions increases growth in children with beta-thalassemia compared to blood transfusions alone.
- Brain tumor. Early research suggests that zinc intake is not linked with a reduced risk of developing brain cancer.
- Canker sores. Some early research suggests that taking zinc sulfate improves canker sores and prevents them from reappearing. However, other research shows no benefit.
- Chemotherapy-related complications. Research suggests that taking zinc by mouth does not affect chemotherapy-related side effects such as nausea and vomiting in children undergoing chemotherapy for leukemia. However, it seems to reduce the number of episodes of infection.
- A lung disease called chronic obstructive pulmonary disorder (COPD). Early research suggests that taking zinc daily after recovery from COPD-related infections reduces the risk of additional infections in older people.
- Colon and rectal cancer. Population research suggests that increased zinc intake is linked to a 17% to 20% reduced risk of colorectal cancer.
- Clogged arteries (coronary artery disease). Early research suggests that taking zinc reduces cholesterol but not triglycerides in people with clogged arteries.
- Memory loss (dementia). Research suggests that taking zinc sulfate improves behavior and social abilities in people with memory loss.
- Dental plaque. Early evidence suggests that brushing teeth with toothpaste containing zinc reduces plaque buildup.
- Diabetes. Research suggests that taking zinc alone or with other nutrients reduces blood sugar in healthy people and in those with diabetes, metabolic syndrome, or obesity.
- Nerve damage caused by diabetes (diabetic neuropathy). Research suggests that taking zinc sulfate improves nerve function and reduces blood sugar in people with nerve damage caused by diabetes.
- Down syndrome. Early research suggests that taking zinc can improve immune function and reduce infections in people with Down syndrome who are zinc deficient and have weakened immune systems. However, other research shows conflicting results.
- Esophageal cancer. Early research has linked low intake of zinc with an increased risk of esophageal cancer. However, other early research shows that zinc intake is not linked with the risk of esophageal cancer. It's possible that the source of zinc (plant vs. meat) affects how beneficial it is.
- Loss of control of bowel movements. Research suggests that applying an ointment containing zinc and aluminum to the anus three times daily for 4 weeks improves symptoms and quality of life in women with a loss of control of bowel movements.
- Stomach cancer. Early research shows that increased zinc intake is not linked to a lower risk of stomach cancer.
- Head and neck cancer. Early research suggests that zinc supplementation does not improve survival rates or reduce the spread of cancer after 3 years in people with head and neck cancer.
- Loss in brain function due to liver problems (Hepatic encephalopathy). Early research suggests that taking zinc may slightly improve mental function in people with hepatic encephalopathy. However, zinc does not appear to improve disease severity or recurrence.
- HIV-related diarrhea. Taking zinc long-term might help prevent diarrhea in adults with HIV who have low blood levels of zinc. However, zinc doesn't seem to help treat diarrhea in adults with HIV-related diarrhea. In children with HIV, some research shows that taking zinc reduces the occurrence of diarrhea compared to placebo (sugar pills). But other research shows that it doesn't help prevent diarrhea compared to vitamin A.
- Fertility problems in men (impotence). Some early research suggests that zinc supplementation increases sperm count, testosterone levels, and pregnancy rates in infertile men with low testosterone levels. Other research suggests that taking zinc can improve sperm shape in men with moderate enlargement of a vein in the scrotum (grade III varicocele). However, in men with fertility problems due to diseases or medical treatment, taking zinc has produced mixed results.
- Stomach infections and parasite infestations. Taking zinc alone or along with vitamin A might help treat some, but not all, parasite infections in children in developing countries. Also, some research suggests that taking zinc with vitamin A reduces the risk for some infections. However, other research suggests that zinc does not reduce the risk for infection.
- Leukemia. Research suggests that taking zinc by mouth helps improve weight gain and reduces infection rate in children and adolescents with leukemia. However, zinc does not appear to improve nutrient levels in the body so that the body can function properly.
- Full-term newborns that are underweight.. Most research suggests that taking zinc supplements during pregnancy does not reduce the risk of having a low birth weight infant. However, adding zinc to nutritional supplementation for underweight, full-term infants in developing countries seems to decrease the risk of death and reduce the risk of some complications. Also, some research suggests that giving zinc supplementation to low birth weight infants from developing countries increases weight gain and length gain. However, zinc supplementation does not appear to improve growth in low birth weight infants from industrialized countries.
- Brown patches on the face (melasma). Research suggests that applying a solution containing zinc to the skin daily for 2 months is less effective than standard skin bleaching treatment for people with brown patches on the face.
- Nose and throat cancer. Early research suggests that taking zinc improves survival rates after 5 years in people with a rare type of advanced nose and throat cancer.
- Jaundice in newborns. Early research suggests that taking zinc twice daily for 7 days does not improve jaundice in newborns.
- Head trauma. Administering zinc immediately after a head trauma seems to improve the rate of recovery.
- A type of cancer called non-Hodgkin's lymphoma. Early research suggests that zinc supplementation is linked to a decreased risk of developing non-Hodgkin's lymphoma
- Obsessive-compulsive disorder (OCD). Early research suggests that taking zinc twice daily along with the drug fluoxetine for 8 weeks reduces OCD symptoms slightly more than taking fluoxetine alone.
- Swelling and ulcers in the mouth caused by chemotherapy, radiation therapy, or hematopoietic stem cell transplantation (HSCT). Research shows that taking zinc sulfate by mouth while undergoing radiation therapy helps prevent ulcers and swelling in the mouth caused by radiation treatments. Some research shows that taking zinc sulfate by mouth reduces the severity of mouth ulcers in adults undergoing chemotherapy. However, taking zinc does appear to improve mouth ulcers caused by chemotherapy in children and adolescents. Zinc does not appear to reduce mouth ulcers in patients undergoing hematopoietic stem cell transplantation (HSCT).
- Prostate swelling (prostatis). Research suggests that taking zinc, selenium, and iodide along with the drug ofloxacin improves symptoms of prostatitis, including pain and quality of life, compared to taking ofloxacin alone. However, taking zinc along with the drug prazosin does not seem to improve symptoms compared to taking prazosin alone.
- High bilirubin levels in the blood caused by HIV/AIDs medications. A class of antiviral medications called HIV protease inhibitors can increase levels of bilirubin in the blood. Early research suggests that taking zinc daily for 14 days decreases total bilirubin levels in the blood by 17% to 20% in people being treated with the HIV protease inhibors atazanavir/ritonavir.
- Itching. Early research suggests that taking zinc twice daily for 2 months reduces itching in people with kidney disease who are experiencing itching due to dialysis treatment.
- Recovery from surgery. Early research suggests that taking zinc reduces the healing time after surgery used to treat an abnormal skin growth located at the tailbone (pilonidal surgery).
- Wound healing. Early research suggests that applying a zinc solution twice daily improves wound healing compared to applying a saline solution. However, applying zinc-containing insulin (Humulin by Eli Lilly and Company) seems to work better than solution containing zinc alone.
- Wrinkled skin. A skin cream containing 10% vitamin C as L-ascorbic acid and acetyl tyrosine, zinc sulfate, sodium hyaluronate, and bioflavonoids (Cellex-C High Potency Serum) applied for 3 months to facial skin aged by sun exposure seems to improve fine and coarse wrinkling, yellowing, roughness, and skin tone.
- Crohn's disease.
- Ulcerative colitis.
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Next: How does Zinc work?
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