ZINC Overview Information
Zinc is a metal. It is called an “essential trace element” because very small amounts of zinc are necessary for human health.
Zinc is used for treatment and prevention of zinc deficiency and its consequences, including stunted growth and acute diarrhea in children, and slow wound healing.
It is also used for boosting the immune system, treating the common cold and recurrent ear infections, and preventing lower respiratory infections. 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; high blood pressure; acquired immunodeficiency syndrome (AIDS); and skin conditions such as psoriasis, eczema, and acne.
Other uses include treating attention deficit-hyperactivity disorder (ADHD), blunted sense of taste (hypogeusia), ringing in the ears (tinnitus), severe head injuries, Crohn’s disease, Alzheimer’s disease, Down syndrome, Hansen’s disease, ulcerative colitis, peptic ulcers and promoting weight gain in people with eating disorders such as anorexia nervosa.
Some people use zinc for benign prostatic hyperplasia (BPH), male infertility, erectile dysfunction (ED), weak bones (osteoporosis), rheumatoid arthritis, and muscle cramps associated with liver disease. It is also used for sickle cell disease and inherited disorders such as acrodermatitis enteropathica, thalassemia, and Wilson’s disease.
Some athletes use zinc for improving athletic performance and strength.
Zinc is also applied to the skin for treating acne, aging skin, herpes simplex infections, and to speed wound healing.
There is a zinc preparation that can be sprayed in the nostrils for treating the common cold.
Zinc sulfate is used in products for eye irritation.
Zinc citrate is used in toothpaste and mouthwash to prevent dental plaque formation and gingivitis.
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.
How does it work?
Zinc is needed for the proper growth and maintenance of the human body. It is found in several systems and biological reactions, and it is needed for immune function, wound healing, blood clotting, thyroid function, and much more. Meats, seafood, dairy products, nuts, legumes, and whole grains offer relatively high levels of zinc.
Zinc deficiency is not uncommon worldwide, but is rare in the US. Symptoms include slowed growth, low insulin levels, loss of appetite, irritability, generalized hair loss, rough and dry skin, slow wound healing, poor sense of taste and smell, diarrhea, and nausea. Moderate zinc deficiency is associated with disorders of the intestine which interfere with food absorption (malabsorption syndromes), alcoholism, chronic kidney failure, and chronic debilitating diseases.
Zinc plays a key role in maintaining vision, and it is present in high concentrations in the eye. Zinc deficiency can alter vision, and severe deficiency can cause changes in the retina (the back of the eye where an image is focused).
Zinc might also have effects against viruses. It appears to lessen symptoms of the rhinovirus (common cold), but researchers can’t yet explain exactly how this works. In addition, there is some evidence that zinc has some antiviral activity against the herpes virus.
Low zinc levels can be associated with male infertility, sickle cell disease, HIV, major depression, and type 2 diabetes, and can be fought by taking a zinc supplement.
- 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, 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.
- 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, applying zinc to the skin in an ointment does not seem to help treat acne uless 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). Taking zinc by mouth might reduce the risk of developing age-related vision loss. Also, taking zinc by mouth together with antioxidant vitamins appears to slow the progression of advanced age-related vision loss. However, taking zinc by mouth alone does not seem to benefit people with age-related vision loss that is not yet advanced.
- Anemia. Giving a porridge that contains zinc and other vitamins and minerals to infants appears to reduce the risk of anemia.
- Anorexia. Taking zinc supplements by mouth might help increase weight gain and improve depression symptoms in people with anorexia.
- Attention deficit-hyperactivity disorder (ADHD). Taking zinc by mouth in combination with conventional treatment might slightly improve symptoms of hyperactivity, impulsiveness, and socialization problems in some children with ADHD. However, zinc might not 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, although it does seem to reduce recovery time.
- Common cold. Taking lozenges containing zinc gluconate or zinc acetate by mouth seems to help decrease the duration of a cold in adults, although some conflicting evidence exists. Taking zinc supplements by mouth does not appear to prevent common colds in adults. 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
- Dandruff. Using a zinc pyrithione shampoo appears to reduce dandruff.
- Depression. Research suggests that taking zinc along with antidepressants seems to improve depression in people with major depression and those who do not respond to treatment with antidepressants alone.
- Foot ulcers due to diabetes. Research suggests that applying zinc hyaluronate gel can help ulcers heal faster than conventional treatment.
- Diaper rash. Giving zinc gluconate by mouth or applying zinc oxide paste to infants with diaper rash appears to improve rash healing.
- Esophageal cancer. Early research has linked low intake of zinc with an increased risk of esophageal cancer.
- 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.
- Bad breath. Research suggests that chewing gum 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). Taking zinc by mouth appears to be 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, zinc may not 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 in people with cirrhosis and zinc deficiency seems to help treat muscle cramps.
- Swelling and ulcers in the mouth caused by radiation therapy. Taking zinc sulfate by mouth seems to be effective for treating ulcers and swelling in the mouth caused by radiation treatments.
- 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. This form of zinc is not available in the US.
- Pneumonia. Some research shows that giving zinc supplements to undernourished children reduces the risk of developing pneumonia. However, the effects of zinc for treating pneumonia once it develops are inconsistent.
- Complications during pregnancy. Taking zinc by mouth during pregnancy appears to reduce the risk for early delivery. 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.
- Pressure ulcers. Taking zinc by mouth or applying zinc paste appears to help improve pressure ulcer healing.
- Prostate swelling (prostatis). Research suggests that taking zinc, selenium, and iodide along with conventional treatment improves symptoms of prostatitis, including pain and quality of life, compared to conventional treatment alone.
- Severe infection complication (sepsis). Research shows that administering a specific product containing zinc (Intestamin) can decrease the risk for organ failure in people with sepsis.
- 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. 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. 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 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 suggests 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.
- 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 seem to help prevent or treat malaria in undernourished children in developing countries.
- 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.
- 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.
- 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 along with blood transfusions increases growth in children with beta-thalassemia compared to blood transfusions alone.
- Brain cancer. 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.
- 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.
- 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.
- 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’s syndrome. Early research suggests that taking zinc can improve immune function and reduce infections in people with Down’s syndrome and weakened immune systems. However, other research shows conflicting results.
- Head and neck cancer. Research suggests that zinc supplementation does not improve survival rates after 3 years in people with head and neck cancer. However, zinc might improve survival rates after 5 years
- Loss in brain function due to liver problems (Hepatic encephalopathy). Research suggests that taking zinc acetate improves some measures of mental function in people with hepatic encephalopathy. However, other research suggests that zinc sulfate does not improve brain function in people with this condition.
- HIV-related diarrhea. Research suggests that taking zinc can reduce the risk of having diarrhea in adults and children with HIV. However, other research suggests that zinc might not be effective in adults who have had diarrhea for 7 or more days.
- Fertility problems in men (impotence). Some early research suggests that taking zinc by mouth does not improve sperm count or sperm movement in men with fertility problems. However, other early research suggests that zinc supplementation increases sperm count, testosterone levels, and pregnancy rates in infertile men with low testosterone levels
- Stomach infections and parasite infestations. Zinc supplementation, alone or together with vitamin A, might be effective for treating some parasite infections in children in developing countries. However, evidence is not consistent. Some research suggests that taking zinc with vitamin A reduces the risk for some infections, while other research suggests that it does not have an effect on the risk for infection.
- Death during childhood. Research suggests that supplementing pregnant women in Nepal with zinc, folic acid, vitamin A, and iron does not reduce the risk of childhood death by the age of 7 years-old compared to vitamin A alone.
- 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. Research suggests that zinc supplementation is linked to a decreased risk of developing non-Hodgkin’s lymphoma
- Full-term newborns that are too small. 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. Also, some research suggests that zinc supplementation increases birth weight and length. However, other research shows no benefit.
- Recovery after surgery. Early research suggests that taking zinc by mouth can reduce healing time after surgery.
- A skin disease called tinea versicolor. Research suggests that using a zinc shampoo once daily for 14 days seems to reduce a fungal skin infection that causes tinea versicolor.
- 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.
ZINC Side Effects & Safety
Zinc is LIKELY SAFE for most adults when applied to the skin, or when taken by mouth in amounts not larger than 40 mg daily. 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.
Zinc is POSSIBLY SAFE when taking by mouth in doses greater than 40 mg daily. There is some concern that taking doses higher than 40 mg daily might decrease how much copper the body absorbs. Decreased copper absorption may cause anemia.
Zinc is POSSIBLY UNSAFE when inhaled through the nose, as it might cause permanent loss of smell. In June 2009, the US Food and Drug Administration (FDA) advised consumers not to use certain zinc-containing nose sprays (Zicam) after receiving over 100 reports of loss of smell. The maker of these zinc-containing nose sprays has also received several hundred reports of loss of smell from people who had used the products. Avoid using nose sprays containing zinc.
Taking high amounts of zinc is LIKELY UNSAFE. 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.
Special Precautions & Warnings:Infants and children: Zinc is LIKELY SAFE when taken by mouth appropriately in the recommended amounts. Zinc is POSSIBLY UNSAFE when used in high doses.
Pregnancy and breast-feeding: Zinc is LIKELY SAFE for most pregnant and breast-feeding women when used in the recommended daily amounts (RDA). However, zinc is POSSIBLY UNSAFE when used in high doses by breast-feeding women and LIKELY UNSAFE when used in high doses by pregnant women. Pregnant women over 18 should not take more than 40 mg of zinc per day; pregnant women age 14 to 18 should not take more than 34 mg per day. Breast-feeding women over 18 should not take more than 40 mg of zinc per day; breast-feeding women age 14 to 18 should not take more than 34 mg per day.
Alcoholism: Long-term, excessive alcohol drinking is linked to poor zinc absorption in the body.
Diabetes: Large doses of zinc can lower blood sugar in people with diabetes. People with diabetes should use zinc products cautiously.
Hemodialysis: People receiving hemodialysis treatments seem to be at risk for zinc deficiency and might require zinc supplements.
HIV (human immunodeficiency virus)/AIDS: Use zinc cautiously if you have HIV/AIDS. Zinc use has been linked to shorter survival time in people with HIV/AIDs.
Syndromes in which it is difficult for the body to absorb nutrients: People with malabsorption syndromes may be zinc deficient.
Rheumatoid arthritis (RA): People with RA aborb less zinc.
Moderate Interaction Be cautious with this combination
- Antibiotics (Quinolone antibiotics) interacts with ZINC
Zinc might decrease how much antibiotic the body absorbs. Taking zinc along with some antibiotics might decrease the effectiveness of some antibiotics. To avoid this interaction take zinc supplements at least 1 hour after antibiotics.
Some of these antibiotics that might interact with zinc include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).
- Antibiotics (Tetracycline antibiotics) interacts with ZINC
Zinc can attach to tetracyclines in the stomach. This decreases the amount of tetracyclines that can be absorbed. Taking zinc with tetracyclines might decrease the effectiveness of tetracyclines. To avoid this interaction take zinc 2 hours before or 4 hours after taking tetracyclines.
Some tetracyclines include demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin).
- Cisplatin (Platinol-AQ) interacts with ZINC
Cisplatin (Platinol-AQ) is used to treat cancer. Taking zinc along with EDTA and cisplatin (Platinol-AQ) might increase the effects and side effects of cisplatin (Platinol-AQ).
- Penicillamine interacts with ZINC
Penicillamine is used for Wilson's disease and rheumatoid arthritis. Zinc might decrease how much penicillamine your body absorbs and decrease the effectiveness of penicillamine.
Minor Interaction Be watchful with this combination
- Amiloride (Midamor) interacts with ZINC
Amiloride (Midamor) is used as a "water pill" to help remove excess water from the body. Another effect of amiloride (Midamor) is that it can increase the amount of zinc in the body. Taking zinc supplements with amiloride (Midamor) might cause you to have too much zinc in your body.
The following doses have been studied in scientific research:
- For treating the common cold: one zinc gluconate or acetate lozenge, providing 9-24 mg elemental zinc, dissolved in the mouth every two hours while awake when cold symptoms are present.
- For diarrhea in malnourished or zinc-deficient children: 10-40 mg elemental zinc daily.
- For preventing and treating pneumonia in undernourished children in developing countries: 10-70 mg/day.
- For hypogeusia (sense of taste is abnormal): 25-100 mg zinc.
- For the eating disorder anorexia nervosa: 100 mg of zinc gluconate daily.
- For treating stomach ulcers: zinc sulfate 200 mg three times daily.
- For muscle cramps in zinc deficient people with liver disease: zinc sulfate 220 mg twice daily.
- For osteoporosis: 15 mg zinc combined with 5 mg manganese, 1000 mg calcium, and 2.5 mg copper has been used.
- For sickle cell disease: zinc sulfate 220 mg three times daily.
- To increase growth and weight gain in children with sickle cell disease who have not reached puberty: 10 mg elemental zinc per day.
- For treating attention deficit-hyperactivity disorder (ADHD) in children: doses of zinc sulfate 55 mg (15 mg elemental zinc) to 150 mg (40 mg elemental zinc) daily.
- For treating acne: 30-135 mg elemental zinc daily.
- For treating age-related macular degeneration (AMD): elemental zinc 80 mg plus vitamin C 500 mg, vitamin E 400 IU, and beta-carotene 15 mg daily.
The typical North American male consumes about 13 mg/day of dietary zinc; women consume approximately 9 mg/day.
The Tolerable Upper Intake Levels (UL) of zinc for people who are not receiving zinc under medical supervision: Infants birth to 6 months, 4 mg/day; 7 to 12 months, 5 mg/day; children 1 to 3 years, 7 mg/day; 4 to 8 years, 12 mg/day; 9 to 13 years, 23 mg/day; 14 to 18 years (including pregnancy and lactation), 34 mg/day; adults 19 years and older (including pregnancy and lactation), 40 mg/day.
Different salt forms provide different amounts of elemental zinc. Zinc sulfate contains 23% elemental zinc; 220 mg zinc sulfate contains 50 mg zinc. Zinc gluconate contains 14.3% elemental zinc; 10 mg zinc gluconate contains 1.43 mg zinc.
APPLIED TO THE SKIN:
- For acne vulgaris: zinc acetate 1.2% with erythromycin 4% as a lotion applied twice daily.
- For herpes simplex infections: zinc sulfate 0.25% applied 8 to 10 times daily or zinc oxide 0.3% with glycine applied every 2 hours while awake.