Healthnotes Newswire (February 1, 2001)—Fighting the symptoms of a common cold is a winter ritual and is also the leading cause of doctor visits and missed school days in the United States. And along with the discomfort and frustration of enduring sneezing, a scratchy throat, and a runny nose, no known cure is available for a cold. However, clinical trials, including one published in the Annals of Internal Medicine, conclude that zinc acetate lozenges may reduce the duration of cold symptoms.¹

The placebo-controlled trial examined the effect of zinc acetate lozenges on the duration of the common cold in 50 adult volunteers from Wayne State University in Detroit, Michigan. At the onset of cold symptoms, volunteers were randomly chosen to take a lozenge containing either 12.8 mg of zinc or a placebo. This was repeated every 2 to 3 hours while awake as long as the cold symptoms lasted.

The researchers found that people taking zinc acetate lozenges had a significant decrease in the severity of cold symptoms, such as sore throat, runny nose, nasal drainage, cough, muscle aches, and headache, compared with those taking placebo. In addition, people taking zinc recovered from their cold in an average of 4.5 days compared with 8 days for the placebo group.

Over the duration of the study, volunteers taking zinc had an average intake of about 80 mg of the trace element per day. While there were no side effects reported in the placebo group, dry mouth and constipation were reported in the zinc group.

Ten previous double-blind trials of zinc’s effect on cold symptoms have netted five positive ^{2 3 4 5 6} and five negative outcomes.^{7 8 9 10 11} The researchers of the current study suggest that the negative results may have been due to the daily amount of zinc being too low and to the type of zinc used in the lozenges.

While short-term (about 4 to 6 days) use of zinc acetate lozenges appears to shorten the duration and severity of the common cold, it’s important to remember that several weeks of high-dose zinc may lead to a deficiency in copper. People taking zinc for more than a couple of weeks are advised to add some copper (about 1 mg per day for every 10–30 mg of zinc) to their daily supplement regimen.