Zinc Supplement (Oral, Parenteral)

Zinc is one of the 24 essential trace elements that are required for the body's normal physiological functioning. It serves as an enzyme co-factor to protect cell membranes from lysis as a result of complement activation and toxin release.


Zinc is a metal. It is called an essential trace element because the body requires it in small amounts to remain healthy. The element is second only to iron in its concentration in the body. Existing in cells throughout the body, zinc plays an important role in the immune system. In addition, it plays a crucial role in cell division and growth, wound healing as well as the breakdown of carbohydrates. Zinc also boosts an individual's sense of taste and smell. The body requires zinc to develop properly during pregnancy, infancy and childhood.

A recent study on zinc supplements showed that:

  • Taking zinc supplements for at least 5 months could reduce an individual's risk of becoming sick with common colds
  • Starting to take the supplements within 24 hours after the onset of cold symptoms may lessen the severity of the symptoms

Symptoms of zinc deficiency

Following are some of the symptoms:

  • Poor appetite
  • Hair loss
  • Frequent infections
  • Problems with senses of taste and smell
  • Hypogonadism in males
  • Skin sores
  • Stunted growth
  • Visual impairment
  • Wounds that take longer to heal

Types of zinc supplements

Different forms of zinc come with different amounts of elemental zinc. You can check the elemental weight on the product's label.

  • Zinc citrate which is approximately 34% zinc by weight
  • Zinc gluconate which is 13% zinc by weight
  • Zinc sulfate which is 22% zinc by weight
  • Zinc monomethionine which is 21% zinc by weight

Some types of zinc that are best absorbed by the body include zinc acetate, zinc citrate and zinc picolinate.

Conditions treated by zinc supplements

Type of medicine

  • Mineral supplement

Side effects associated with zinc supplements

Zinc supplements may cause some undesired effects to the body. While some side effects are benign, others are not. You are advised to seek medical attention if you exhibit some of these zinc side effects.

  • Persistent ulcers or sores in the mouth and throat
  • Chills
  • Heartburn
  • Fever
  • Nausea
  • Indigestion
  • Dizziness, fainting, shortening of breath and unusual tiredness or weakness
  • Vomiting
  • Yellow eyes and skin

Call your doctor or report to the FDA at 1-800-FDA-1088 if you experience zinc overdose.

Zinc supplements dosage

Zinc has two dosage standards - the low dosage at 5-10 mg and high dosage at 25-45 mg. Low dosage is recommended as a daily preventive while the high dosage is prescribed for individuals suffering from zinc deficiency. The intestinal uptake of zinc can be hindered by other minerals such as magnesium, calcium and iron since they all use the same transporting agent.

Zinc supplements should be taken on a daily basis, especially if you are a vegetarian, expectant or nursing. While superloading (taking up to 100 mg of zinc per day) has been confirmed as safe in the short term, it is important to note that this dosage is higher than the element's Tolerable Upper Limit (TUL). Thus, the prolonged superloading of zinc beyond 2-4 months is not recommended.

Oral zinc supplements

The Recommended Dietary Allowance (RDA) for zinc supplements has been established as follows:

  • Boys and men aged 14 and older: 11 mg/day
  • Women aged 19 and older: 8 mg/day
  • Expectant women aged 14 - 18: 14 mg/day
  • Lactating mothers aged 19 and older: 12 mg/day

Tolerable Upper Intake (UL) of zinc for individuals not receiving the supplement under medical supervision:

Adults aged 19 and older, including expectant and nursing mothers: 40 mg/day.

For individuals suffering from zinc deficiency: People who are suffering from zinc deficiency are advised to take two to three times the recommended dietary allowance (RDA) for up to 6 months. People who suffer from moderate to severe deficiency are advised to take four to five times the RDA for up to six months.

For diarrhea: To prevent diarrhea in newborns, expectant mothers are advised to use 15mg of zinc with or without 60 mg of iron from week 10 of the pregnancy through to child birth.

For treating Wilson's disease: The FDA has approved zinc acetate for the treatment of Wilson's disease. Patients are advised to take 25-50 mg of zinc supplements three to five times a day.

For treating acne: 30-150 mg of the supplement is recommended daily.

For treating acrodermatitis enteropathica (a hereditary disorder that affects zinc uptake): Patients are advised to take 2-3mg/kg of elemental zinc on daily basis for a lifetime.

For age related vision loss: A combination of 80 mg of elemental zinc, 500 mg of vitamin C, 2 mg of copper, 15 mg of beta-carotene and 400 UI vitamin E should be taken daily for up to 5 years or until there is improvement in one's vision.

For anorexia nervosa: 14-50 mg of elemental zinc is recommended daily.

For managing a common cold: A patient may dissolve one zinc gluconate or zinc acetate lozenge containing 5-25 mg every two hours while awake to manage a common cold.

For depression and anxiety: 25 mg of elemental zinc should be taken daily alongside other antidepressants for up to 12 weeks.

For smell and taste disorders: 140-450 mg of zinc gluconate should be broken down into three daily doses for up to four months. Also, 25 mg of elemental zinc may be used daily for six weeks.

For muscle cramps: 220 mg of zinc sulfate should be taken daily for up to 12 weeks.

For warts: Take 400-600 mg of zinc sulfate daily for 2-3 months.

Zinc supplements dosage in children

The Institute of Medicine has set the Adequate Intake (AI) levels of zinc for infants from birth to 6 months at 2 mg/day. The RDA for older infants and children, 7 months to 3 years, is 3 mg/day. Children aged 4-8 years should take 5 mg/day while those aged 9-13 should take 8 mg/day. Girls aged 14-18 should take 9 mg of zinc per day.

The Tolerable Upper Intake Levels (UL) for minors who are not receiving zinc under medical supervision are as follows:

  • Infants from birth to 6 months: 4 mg/day
  • Toddlers 1-3 years: 7 mg/day
  • Children 4-8 years: 12 mg/day
  • Children 9-13 years: 23 mg/day
  • Teenagers 14-18 years, including expectant and nursing mothers: 34 mg/day

Zinc interactions

Studies have shown that zinc decreases plasma concentrations of certain quinolone (like ciprofloxacin) and tetracycline antibiotics. It can also interfere with absorption and metabolism of Vitamin A, copper and iron.

Zinc interactions with medications

Zinc supplements have been known to interact with several types of medications. Individuals on the following medications should consult their healthcare providers before taking zinc supplements:

  • Antibiotics

Quinoline antibiotics like Cipro and tetracycline antibiotics like Sumycin and Achromycin interact with zinc in the gut to inhibit the absorption of both the antibiotic and zinc. You can minimize the interaction by taking the antibiotic 4-6 hours before taking the zinc supplement.

  • Penicillamine

Zinc is known to reduce the absorption and action of penicillamine, the drug used in the treatment of rheumatoid arthritis. Individuals on this medication are advised to take the supplement at least 2 hours before or after taking penicillamine.

  • Diuretics

Thiazide diuretics like chlorthalidone (brand name Hygroton) and hydrochlorothiazide (brand names HydroDIURIL and Esidrix) have been known to increase urinary zinc excretion by up to 60%. Prolonged use of these diuretics can thus deplete an individual's zinc tissue levels.

  • Cephalexin (kelfex)

This is an antibiotic used for treatment of infections. Zinc reduces cephalexin absorption if taken at the same time or less than 3 hours before cephalexin. This might affect the drug's effectiveness in treating infections. Patients using cephalexin (Kelfex) are advised to take zinc supplements 3 hours after the antibiotic.

Zinc interactions with herbs and other supplements

  • Beta-carotene

High doses of zinc can lower beta-carotene blood levels.

  • Bromelain

Zinc reduces the effect of bromelain.

  • Calcium

Calcium supplements have been found to lower dietary zinc absorption. The interaction can be avoided by taking calcium supplements when going to bed rather than with meals.

  • Copper

Large doses of zinc (150mg/day or more for 2 years) can reduce copper absorption resulting in copper deficiency and anemia.

  • EDTA

EDTA is a chemical compound prescribed to individuals with excess lead in their systems. High doses of EDTA can deplete blood zinc levels by up to 40%.

Zinc interactions with food

  • Coffee

Taking zinc sulfate with black coffee instead of water can reduce zinc absorption by up to 50%.

  • Dairy products and calcium fortified foods

Calcium is known to inhibit zinc absorption. The significance of excessive loss of zinc is minimal unless an individual consumes high quantities of calcium supplements.

  • Fiber

Fiber consumption can reduce zinc absorption. The body can, however, adjust to increased fiber in the diet by increasing zinc absorption.

  • Phytate

This is a molecule found in grains, legumes and soy. Phytate is known to reduce zinc absorption.

  • Fiber

Eating fiber can reduce zinc absorption. However, over time the body adapts to increased dietary fiber by increasing zinc absorption.

  • Protein

Zinc binds onto proteins, becoming available for absorption when the protein is digested. Animal protein, except that in cow's milk, is known to increase zinc absorption. Soy, on the other hand, reduces zinc absorption due to its high phytate content.

Zinc and vegetarianism

Vegetarian diets are often made up of legumes and proteins, so they are high in phytate. Zinc absorption is thus lower, making this diet a risk factor in zinc depletion.


  • Health risks from zinc overdose

Zinc toxicity can occur in both chronic and acute forms. Some of the adverse effects of zinc toxicity include vomiting, nausea, abdominal cramps, loss of appetite, headaches and diarrhea. That said, it is important to note that most zinc supplements also contain another metal called cadmium, which coexists naturally with zinc. Exposure to high doses of cadmium over an extended period of time have been linked to kidney failure. The concentration of cadmium in zinc supplements can be as much as 37-fold. Thus, when purchasing zinc supplements, look out for zinc-gluconate supplements. These zinc supplements contain lower cadmium levels.

  • Zinc supplements and alcohol intake

Excessive alcohol drinking over a long period can result in poor zinc absorption in the body.

  • Diabetes

Large doses of zinc can lower blood sugar levels in people with diabetes. Thus, diabetic people should use zinc supplements cautiously.

  • Hemodialysis

Individuals on hemodialysis treatment tend to be at risk for zinc deficiency and are advised to take zinc supplements.

  • HIV (Human Immunodeficiency Virus)/AIDS

Zinc use has been linked to a shortened survival period in people suffering from HIV/AIDS. Consult your doctor before using these supplements if you are suffering from the condition.

Zinc supplement storage

Always keep your supplements out of reach of children. For optimal potency, store your zinc supplements in the original containers away from moisture, heat and direct sunlight. Keep them from freezing. Get rid of all outdated supplements appropriately.


Zinc, commonly referred to as "essential trace element", is one of the 24 micronutrients required by the body in very small amounts for proper physiological function. It is found in eggs, red meat, fish, and most legume products. Since the human body cannot store zinc, it is consumed regularly as part of the diet. Depending on severity, zinc deficiency can cause stunted growth in minors, loss of vision, hindered ability to smell or taste food and poor testes and ovary development, among other effects. Zinc is ingested through the mouth to prevent its deficiency and the consequences already mentioned.

Zinc is also used to boost the body's immune system. It is also taken to help treat rheumatoid arthritis, osteoporosis, warts, psoriatic arthritis as well as muscle cramps in patients with liver problems. It is also used for sickle cell disease, hair loss, rosacea, psoriasis, acne, eczema, Alzheimer's disease, a blood disorder called thalassemia, Hansen's disease, Down syndrome and cystic fibrosis.

Patients also take zinc supplements for different types of cancers, including esophageal cancer, stomach cancer, colon and rectal cancer, head and neck cancer recurrence, brain cancer, nasal and throat cancer recurrence and non-Hodgkin's lymphoma. It is also taken orally to prevent inflammation in the digestive track's lining, anemia, complications resulting from chemotherapy as well as pregnancy related complications. Some athletes also use zinc to boost their strength and performance.

Zinc is an aphrodisiac and testosterone booster. However, it only raises testosterone levels if the user is suffering from zinc deficiency. Taken in high doses, however, zinc can act as an aromatase inhibitor, reducing an individual's estrogen levels. It can also serve as an antioxidant to the prostrate. Zinc can be lost from the body through sweat, making supplements very essential for athletes who do not get adequate zinc through their diet.

Last Reviewed:
December 24, 2017
Last Updated:
April 27, 2018
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