Zinc: Benefits, Side Effects & Dosage

What is Zinc?

Zinc is a trace mineral, the second-most abundant in the human body behind iron. Since we can’t produce it naturally, we have to get this important micronutrient from our food and water or from supplements.

Research has established several critical roles that zinc plays in the body. We need it for a properly functioning immune system, a strong cardiovascular system and for the health of our eyes and skin. However, as important as it is, getting too much can have harmful effects. We only need small amounts of it to maintain good health.

Benefits of Zinc

Zinc deficiency puts you at risk of getting sick. In addition to colds and chronic disease, people become more susceptible to infections that cause diarrhea and pneumonia (x).

Zinc plays a vital role in the human body, even in tiny amounts. There are over 1,000 enzymes that need it to function. It assists with immune function, healing wounds, cell division, growth and the synthesis of protein and DNA (x). Here are some areas that it can benefit:

Immune Function

Cold Prevention

Studies show that when we take zinc in the form of lozenges or syrup, it can reduce the duration and severity of cold symptoms by about 33 percent. Some research suggests that it needs to be present in a dose ranging from 75 to 200 mg, but researchers are still investigating the optimal dose. But the key is to take it in the first 24 hours of a cold (x, x).

Immune System Defense

However, the immune system is not just there to fight colds. It protects the body from developing diseases in the first place. For example, diabetes and heart disease can develop when the immune system is unable to combat inflammation and oxidative stress. Because it acts as an anti-inflammatory and an antioxidant, research suggests that when we don’t get enough of it or when it doesn’t metabolize properly, it can increase the risk of developing these types of conditions (x).

Autoimmune Defense

Zinc can also play a protective role against autoimmune conditions, which develop when the immune system erroneously attacks healthy cells (x).

Heart Health

Cardiovascular diseases (CVD) are a group of disorders that affect the heart and blood vessels. They are also the number one cause of death worldwide, causing heart attacks and strokes (x).

However, zinc can help keep the cardiovascular system healthy. First, it helps reduce the buildup of plaque in the arteries. Second, when plaque does accumulate, it can keep it from oxidizing, which prevents inflammation. Finally, it strengthens the cells that line blood vessels (x). Population studies show that patients with adequate zinc are 43 percent less likely to experience CVD death.



Human skin contains the third highest concentration of zinc in the body. It ensures that new skin cells are healthy (x). A deficiency can cause a variety of skin conditions, slow down wound healing and cause hair loss and acne.

But supplements can help. Studies show that acne, wounds and skin ulcers, for example, heal faster with a supplement regardless of the person’s zinc status (x).


After a severe burn, the body can lose large amounts of zinc through the wound and through urine, which slows down the body’s ability to heal itself. Studies show that oral and topical supplements help reduce inflammation and encourage healthy new cell growth (x, x). Research also demonstrates that topical creams help protect the skin from UVA and UVB-induced damage (x).

Diaper Rash

An interesting study examined the relationship between zinc levels in healthy babies and diaper rash. The babies with higher levels (measured through hair samples) had less frequent bouts of diaper rash. Regardless of their zinc status, however, a topical cream prevented diaper rash more effectively than talcum powder, but without the respiratory hazards that come with the powder (x).


Like the skin, zinc is highly concentrated in the retina and a deficiency can affect your vision (x). The Age-Related Eye Disease Study (AREDS) found that supplementation significantly improved outcomes for those most at risk of developing advanced age-related macular degeneration. The researchers tested various doses and found that 25 mg worked just as well as 80 mg. In other words, a higher dose was not any more effective in this case (x).

Oral Health

Saliva, dental plaque and tooth enamel all contain zinc. Toothpaste with zinc can prevent plaque development or help remove existing plaque, treat gingivitis and bad breath, as well as remineralize teeth (x).

Mental Health

Researchers are currently exploring the link between zinc and mental health, specifically in women with depression and children with ADHD symptoms. Researchers have discovered that it is important for proper neuronal development and modulation of neurotransmitters, including those involved with depression and anxiety symptoms.

Research is still emerging, but population studies and clinical trials suggest that supplementation may help reduce symptoms of depression and ADHD in some cases (x).

Male Reproductive Health

Maybe you’ve heard that oysters are aphrodisiacs. But do you know why? Zinc plays a big role in men’s reproductive health. Seminal fluid has a high zinc concentration that allows sperm to develop and function properly, while maintaining healthy male hormone levels. Interestingly, its antibacterial action in semen helps protect the sperm from bacteria found in the vagina, improving the chances of conception (x).


Test tube studies show that zinc can prevent the herpes virus from replicating, which prompted scientists to try zinc therapy on people with HSV-1 and HSV-2. A study involving 100 men with genital herpes applied a topical cream for six months. Their lesions healed faster and recurred less often (x).

Zinc Benefits

Correcting Zinc Deficiency with Supplements

Zinc deficiency is more common in the developing world, but it occurs worldwide. Symptoms of a deficiency include irritability, loss of appetite, flaky skin, hair loss, diarrhea, nausea, reduced sense of taste and smell and low insulin levels.

Risk Factors

People who suffer from malnourishment, adults over the age of 60, those with certain gastrointestinal or kidney disorders, pregnant women and people addicted to alcohol are most at risk of deficiency (x).


Diarrhea is especially common among children in developing countries and can be attributed to low zinc intake, which can then aggravate a deficiency. Supplements can help to reduce the severity and extent of diarrhea, particularly in malnourished children. Pregnant and nursing women sometimes take it to reduce the chances of diarrhea in infants (x).

Wilson’s Disease

Finally, zinc supplements help to minimize the symptoms of a rare inherited disease called Wilson’s Disease, which causes copper to accumulate in the body. The supplement prevents excessive copper absorption and increases the amount of copper that the body expels.

Types of Zinc Supplements

As a supplement, zinc combines with other compounds, called chelating agents, that help the body absorb it (x). There are several types of chelating agents. Each type of supplement contains different amounts of elemental zinc, so it’s important to follow the dosage instructions on the labels. Here are some common supplement forms you’ll find:

Zinc Gluconate

This form of zinc is chemically bonded with gluconic acid. Zinc gluconate is among the best absorbed forms and is used in many over-the-counter cold remedies (x).

Zinc Citrate

This form combines elemental zinc with citric acid. Studies show that the body absorbs zinc citrate well, comparable to zinc gluconate (x, x).

Zinc Orotate

Combined with orotic acid, a molecule required for the regulation of genes that are involved in cell and tissue development, zinc orotate is a popular and well-absorbed supplement (x, x).

Zinc Oxide

This is a common ingredient in topical treatments for treating burns, rashes and irritations. Zinc oxide is also present in sunscreen (x).

Zinc Glycinate

When combined with glycine, an amino acid that helps topical absorption, this form is a common ingredient in skincare products. Since vegetarian diets high in phytates can decrease the absorption of dietary zinc, vegetarians might choose zinc glycinate since it absorbs well even in the presence of phytates (x).

Zinc Dosages

Dosage varies depending on the type of supplement you intend to use. Each type of supplement contains different amounts of zinc. The recommended daily allowance (RDA) of elemental zinc for adult women and men is 8 mg and 11 mg per day, respectively. The Tolerable Upper Intake Level (UL) is the amount that most healthy adults can tolerate without negative side effects, set at 40 mg per day for men and women (x). Supplement labels should clearly state how much will be in each serving.

Zinc Side Effects

Some people may experience various side effects from zinc supplementation including:

  • Nausea
  • Abdominal discomfort
  • Diarrhea
  • Vomiting

Topical application may cause side effects as well such as:

  • Itching
  • Stinging
  • Tingling sensations



Too much zinc may inhibit the body’s ability to absorb copper, which may lead to anemia and other health problems. If you are taking more than 50 mg of elemental zinc per day, consider supplementing with iron and especially copper (x).

Prostate Cancer

Prolonged use of a high-dose supplement may increase the risk of prostate cancer (x).

Pregnancy or Breastfeeding

Pregnant and nursing women should talk to their doctors before using these supplements. Zinc overdose is unsafe for pregnant and breastfeeding women (x).

Other Warnings

Zinc supplements can interfere with prescription drugs including (but not limited to) antibiotics, diuretics and penicillamine. If you take any medications, check with your doctor before supplementing (x).

In addition, never take zinc through a nasal spray because it may cause permanent loss of the ability to smell (x).

The Bottom Line

Zinc is critical for the human body. It’s necessary for proper growth and development, a healthy immune system and to control inflammation. People assume extreme and overt deficiencies occur mainly in developing countries, but others believe that mild deficiencies are more widespread.

Lack of sufficient zinc in the body causes a wide variety of symptoms and disorders. Some of these symptoms can be reversed with supplements, while others cannot.

The body can’t make zinc on its own. Luckily, many people can receive adequate amounts of it by consuming a diet rich in seafood, meat, dairy and fortified grains. Supplements are also available in many different forms. As important as zinc is, however, more is not necessarily better! It’s important to get the right amount for your body. If you’re unsure, ask your healthcare professional.

Author: James D