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TThere is no proven cure for the common cold, but many people do remedies they swear by it when they feel bad. (Chicken soup or citrus, anyone?) A common strategy is to take tablets or lozenges containing zinc, a natural mineral found helps the immune system fight back against bacteria and viruses.
But many experts don’t recommend people drop zinc tablets at the first sign of sniffing. Dr. Katharine DeGeorge, a family physician at the University of Virginia, who has done just that studied cold medicinesis one of them. “Some people may benefit from it,” she says. “But that comes at a cost: monetary costs, and also the risk of adverse events.”
Zinc users have some science to support their decision. Some research suggests that zinc may prevent the common cold virus from binding to cells in the body and copying itself, potentially shortening the duration of an illness. (Some scientists have investigated whether zinc has the same effect against other viruses, such as those that cause influenza and COVID-19, but there isn’t much data to support this hypothesis, says Dr. Roy Gulick, chief of infectious diseases at Weill Cornell Medicine and NewYork-Presbyterian. ) Adults who start taking about 80 mg of zinc per day within 24 hours of a cold will feel better faster than those who don’t take zinc. some studies to suggest.
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A recent one Cochrane review article confirmed this finding, based on an analysis of 34 previously published studies on zinc and the common cold. The authors found no evidence that proactively taking zinc can prevent a cold, but they did find some evidence that taking it during illness speeds recovery by about two days.
Fewer sick days sounds great, right? Not so fast, says Daryl Nault, an assistant professor at the Maryland University of Integrative Health and co-author of the Cochrane review article.
She and her fellow researchers rated their results as “low certainty” because the studies in the review were spread across the map, covered different forms and doses of zinc, and were designed with varying levels of scientific rigor. “We don’t really have enough evidence to draw a firm conclusion from it,” she says. “At best, we have seen this to be the case possible that it could reduce the average duration of a cold by a few days.”
But, DeGeorge says, not everyone benefits from taking zinc, and it often causes side effects such as stomach upset, headaches and a bad aftertaste. Taking zinc in doses high enough to be effective — about 80 mg per day, according to studies on the subject — increases the chance of experiencing these symptoms, she says.
“At some point you replace the symptoms of your cold” with new ones, says Nault. There may be cases where dealing with these side effects is worth it, such as if you are going on holiday and want to get better before you leave. (In fact, the US Centers for Disease Control and Prevention mentions zinc as a potential tool for travelers.) But other times, she says, you might as well sit back and conquer your cold symptoms.
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People who take very high doses of zinc for a long time can also experience problems a range of complications– including neurological problems and, ironically, getting sick more often. Taking a product marketed for cold relief for the limited period of time you have symptoms shouldn’t put you at risk for serious complications, DeGeorge says, but don’t go overboard. And the Mayo Clinic says never to do that use nasal sprays that contain zinc as they can damage your sense of smell. (These products are rare anyway, according to the U.S. Food and Drug Administration told consumers to stop using it in 2009.)
Given zinc’s uncertain benefits and potential harms, Gulick says he doesn’t routinely recommend it to his patients. People looking to relieve their symptoms are probably better off with over-the-counter medications such as decongestants and sore throat lozenges, he says.
DeGeorge also says she typically recommends people save their money and avoid zinc side effects by focusing on the basics: staying home, getting plenty of rest and drinking plenty of fluids. A cold “will go away on its own no matter what you do,” she says. “It’ll suck for a week, but it’s okay.”
Write to Jamie Ducharme at [email protected].