When a cold strikes your first reaction may be to reach for a remedy that will ease symptoms or shave a few days off your illness. And for millions of Americans each year, that includes trying dietary supplements, including echinacea, vitamin C, and zinc.

Here's what those supplements can and can’t do when it comes to treating the common cold—as well as some simple strategies that can prevent you from getting sick in the first place. Plus, advice on treatments that can help relieve cold symptoms if you're already under the weather.

Echinacea

Supplements containing this plant vary widely in composition, making them difficult to study. There are several species, and preparations can contain flowers, roots, or leaves. That said, a number of trials have examined the plant’s effect on colds. “A few early studies showed promise,” says Consumer Reports chief medical adviser Marvin M. Lipman, M.D. explains, “but more recent research has failed to prove that echinacea helps to fight off colds or soothe cold symptoms.” 

Vitamin C

Regularly getting 200 mg per day of vitamin C might shorten your cold by a day or so, according to a 2013 Cochrane review of 29 trials involving 11,306 study participants. “But flooding your body with that vitamin won’t knock out the virus once it takes hold,” Lipman says. And it isn’t risk-free: Vitamin C may increase the risk of kidney stones, and high doses can cause diarrhea, Lipman says.  

Zinc

Research in the July 2016 issue of the British Journal of Clinical Pharmacology found that regularly sucking zinc lozenges (totaling 80 to 90 mg per day) throughout a cold may shorten it by almost three days. But, Lipman points out, “zinc won’t ease symptoms, and its side effects, including diarrhea, nausea, and a lingering metallic taste, may add to your miseries.”  

What to Do Instead

To soothe cold symptoms, rest and drink plenty of liquids. Warm drinks or hot soup may loosen nasal secretions, which helps drain sinuses. You can also try sucking on nonmedicated lozenges. To relieve aches and pains, try over-the-counter painkillers such as acetaminophen (Tylenol and generic) or ibuprofen (Advil and generic).

To prevent colds, wash your hands regularly. Researchers at the University of Colorado at Boulder found that the average hand has about 150 species of bacteria. “Avoid touching your mouth, nose, and eyes—the primary ways bacteria and viruses enter your system,” Lipman says. And get plenty of sleep. Research led by Sheldon Cohen, Ph.D., director of the Laboratory for the Study of Stress, Immunity and Disease at Carnegie Mellon University in Pittsburgh, recently found that when study participants were infected with rhinovirus (which can cause colds) those who slept less than 6 hours per night were significantly more likely to develop a cold than those who slept for more than 7 hours. According to Cohen, a good amount for keeping our immune systems in good working order is 7 to 8 hours per night.