As sniffle season settles in across the United States, many families wonder whether over‑the‑counter zinc lozenges are a worthwhile remedy for the common cold. The question has been examined in a recent systematic review published by the Cochrane Database of Systematic Reviews, which evaluated 34 studies on zinc’s role in preventing or treating colds.
What the science says
The Cochrane authors concluded that regular zinc supplementation offers little to no benefit in preventing a cold. However, when zinc is used as a treatment after symptoms appear, the review suggests a modest reduction in illness length—approximately 2.4 days compared with a placebo. Despite this finding, the reviewers expressed “little confidence” in the overall evidence, noting variability in study quality and dosing.
Why results differ
Dr. Harri Hemilä, a Finnish researcher who has studied zinc and colds for decades, explained that differences in dosage and formulation likely drive the mixed outcomes. In the 34 studies examined, daily zinc doses ranged from a mere 0.044 mg to a high 296 mg, and the products tested included zinc acetate, zinc gluconate, and zinc orotate in lozenge, nasal spray, or syrup form.
Hemilä’s own 2011 systematic review of 13 studies found that daily doses below 75 mg had no measurable effect on cold duration, while doses above that threshold showed a benefit. “The greatest problem with using zinc lozenges to treat colds is the difficulty in finding proper lozenges,” he said, noting that many commercial products contain insufficient zinc or include ingredients such as citric acid that bind zinc and reduce its availability.
Practical considerations for consumers
Common brands like Cold‑EEZE provide roughly 11–13 mg of zinc per lozenge. To reach the 75 mg level associated with a potential benefit, a user would need to take six to seven lozenges daily—more than the dosage instructions on most packages. Higher doses can cause side effects, including an unpleasant metallic taste, nausea, and diarrhea. The FDA has also warned that some zinc nasal sprays have been linked to permanent loss of smell, prompting cautions about their use.
Dr. Mark H. Ebell, a family‑medicine professor at Michigan State University, emphasized that short‑term use of zinc lozenges appears safe for most adults, stating, “As far as we know, there are no serious risks to taking the lozenges for a few days.” Nonetheless, he reminded readers that the recommended dietary allowance for zinc is 8–11 mg per day for adults, and regular intake should not exceed 40 mg to avoid adverse effects such as copper deficiency.
Should you try zinc?
For someone battling a severe cold, a trial of higher‑dose zinc lozenges may be reasonable, but expectations should be modest. The potential to shave a couple of days off a cold must be weighed against the inconvenience of taking multiple lozenges daily and the possibility of side effects.
Health professionals advise consulting a physician before beginning any new supplement regimen, especially for individuals with underlying medical conditions or those taking other medications.
Bottom line
Current research suggests zinc lozenges can modestly reduce the duration of a cold when taken at sufficiently high doses, but the evidence is not robust. Consumers should be cautious about dosage, product quality, and possible side effects, and should view zinc as a possible adjunct rather than a cure.
Original reporting: 40/29 / KHBS (NW Arkansas) — read the source article.
