The Cochrane Collaboration is a very well-respected international non-profit whose 28,000 volunteers review the best, solid evidence to help determine if medications or other health interventions really work. They are, in short, da bomb.

When Cochrane speaks, people listen.

Cochrane recently released a review of studies examining the effectiveness of zinc supplementation on preventing and treating the common cold.

They found that there was good evidence that zinc taken early, during the first symptoms of a cold, can lessen the duration and severity of illness; furthermore, zinc taken daily during cold season can reduce the frequency of these annoying infections.

There were only 15 good quality studies to look at, involving a total of about 1400 patients. Because the studies varied in how much zinc was given, in what form, and how often, no conclusion could be drawn about the best dosing strategy. Nor could any conclusions be drawn about using zinc in children. Still, the evidence tantalizing, and more research is needed to pin down these details.

Zinc is fairly well-tolerated and safe. The most common side effects reported were an unpleasant taste and nausea. There is no particular reason to think zinc in reasonable doses would be unsafe in children or adults.

If you want to try zinc, there are drops, lozenges, and pills to choose from of varying strength and composition. Follow label directions for dosing. For these products to work to treat the cold, you have to start them quickly, and take them frequently throughout the day.

One other warning: the Cochrane review was looking at genuine, therapeutic doses of zinc. Many other zinc products are produced and marketed as “homeopathic”—meaning there isn’t any actual zinc in the bottle. Homeopathy is literally nothing. It’s a kind of witchcraft that relies on the nonexistent magical memory of water. Don’t waste your money on anything labeled “homeopathic.” If you want to try zinc, choose a genuine zinc product that measures the dose in milligrams, not in magic memories.

Roy Benaroch is a pediatrician who blogs at The Pediatric Insider. He is also the author of Solving Health and Behavioral Problems from Birth through Preschool: A Parent’s Guide and A Guide to Getting the Best Health Care for Your Child.