Most colds last seven to 10 days. During that time, cold symptoms — like sneezing, sniffling, and a stuffy nose — can make you feel miserable. Many people want to take something to help them get through a cold faster.
One supplement that’s received attention when it comes to shortening the duration of a cold is zinc. But does it really work? Here’s what you should know before taking zinc for colds.
What Is Zinc?
Zinc is an essential micronutrient found in cells throughout your body. It’s found in many foods, and it’s also available in various supplement forms.
Zinc is a trace mineral, so your body only needs a small amount of it to stay healthy. Most people in the U.S. get enough zinc in their daily diets. Because your body can’t store zinc, you need a small but steady supply.
For adults age 19 and older, the U.S. Recommended Dietary Allowance (RDA) for zinc varies slightly.
- Adult men need 11 mg.
- Adult women you need 8 mg.
- Pregnant women need 11 mg.
- Breastfeeding women need 12 mg.
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Food Sources of Zinc
Fortified cereals typically contain added zinc. Other good food sources of zinc include:
- Whole grains
- Dairy products
- Red meat
- Baked beans
How Does Zinc Help the Immune System?
When you don’t have enough zinc, your immune system can’t do its job. Research on children in developing countries shows that low zinc levels increase the risk of getting pneumonia and other infections.
The same was true for older adults. That’s because these two groups may not get enough zinc from the food they eat.
Zinc supports how immune cells grow and function. Even a small or medium deficiency can impact how effectively your immune cells protect your body from bacteria and viruses.
Can Zinc Prevent or Treat a Cold?
Researchers have studied zinc since the 1990s to see if taking zinc supplements could prevent or treat a cold. So far, the research finds that zinc supplements don’t appear to help prevent you from getting a cold.
But oral zinc lozenges may help shorten how long you have cold symptoms. According to the National Institute of Health’s Office of Dietary Supplements, research so far has found that zinc may:
- Help shorten the duration of cold symptoms by two or three days compared to those who don’t take zinc supplements.
- Help reduce the severity of symptoms in the first three days. But after that initial reduction, zinc supplements did not reduce the severity of overall symptoms.
How to Take Zinc for Colds
Doctors won’t recommend zinc for the common cold until there is more data to support using it. So there aren’t any standard guidelines for using zinc for colds. Based on the research to date, here’s how to take zinc to potentially shorten your cold symptoms:
- Start taking oral zinc lozenges within 24 hours of first feeling cold symptoms.
- Take a total of 80 mg to 92 mg per day. That’s the amount used in several studies that showed benefit of zinc lozenges.
- Don’t take them longer than two weeks. Long-term use of zinc, especially in high doses, can cause several problems. This includes copper deficiency, increase in urinary tract infections, and even reduced immune function.
- Avoid using zinc nasal sprays. These can cause you to lose your sense of smell, either long-term or permanently. It’s a serious side effect known as anosmia.
Are Zinc Supplements Safe?
When taken for a short period of time and in low doses, zinc appears safe. But because zinc is a trace mineral and most people get enough zinc in their diet, it’s possible to get too much zinc even from low-dose supplements.
Taking too much zinc can cause metallic taste, nausea, vomiting, diarrhea, headaches, abdominal cramps, and loss of appetite.
“The medical community is always on the search for a way to better treat the symptoms of the common cold, and zinc and other supplements are no exception. This is likely a safe option for you to try in addition to staying well hydrated and getting adequate rest,” says Alyssa D’Addezio, MD of Greater Pittsburgh Medical Associates-UPMC.
So, what is too much zinc? For men and women ages 19 and older, experts advise that 40 mg of zinc is the tolerable upper limit (UL). That’s the amount you shouldn’t go over unless you are using zinc for medical treatment and under a doctor’s care.
Long-term use of zinc lozenges above the UL increases your risk of serious side effects.
Zinc may also interfere with other medications you are taking. These include antibiotics, penicillin, and diuretics. If you are taking antibiotics for a bacterial infection, don’t take zinc.
Oral zinc lozenges can cause nausea or gastrointestinal issues. If you have these side effects, stop taking zinc. It could be a sign that you’re taking too much.
Talk to your doctor to find out whether zinc may help you during a cold. Your doctor can also give you other tips on how to feel better during a cold.
Common Colds: Protect Yourself and Your Family. Centers for Disease Control and Prevention. Link.
Zinc: Fact Sheet for Consumers. National Institute of Health. Office of Dietary Supplements. Link.
Zinc: Fact Sheet for Health Professionals. National Institute of Health. Office of Dietary Supplements. Link.
The Common Cold and Complementary Health Approaches. NCCIH Clinical Digest. National Center for Complementary and Integrative Health. Link.
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