HELSINKI — Zinc acetate lozenges may help relieve an itchy throat momentarily, but they won’t help you get over a cold any faster, a new study finds. Researchers at the University of Helsinki just performed a randomized trial on patients suffering from the common cold, and concluded that using these popular lozenges, despite their claims, didn’t shorten the duration of their symptoms at all.
These findings are the latest in a series of contradicting research efforts on the effects of zinc lozenges on the common cold. As many as eight previous studies had found that they do help resolve cold symptoms faster, while others have come to the same conclusions as the research team in Helsinki. These varying findings are puzzling, but some have pointed to differences in the types of lozenges used as one possible explanation. For example, many of the studies that had found lozenges didn’t help shorten colds had used lozenges with low levels of zinc or other ingredients like citric acid.
In this latest study, researchers performed a randomized, double-blind placebo-controlled trial on Helsinki city employees dealing with colds. To make sure all the participants started taking lozenges at around the same time, each person was given a packet of lozenges and told to start using them as soon as they felt a cold coming on. Each person was told to take six lozenges a day for five days, which worked out to 78 mg of zinc on a daily basis. However, half of the participants were actually given placebos that contained no zinc at all.
In total, 88 participants took part in the research. There was absolutely no difference in recovery time among participants in the experimental and placebo groups during the five day treatment period. In fact, those who took real zinc lozenges actually ended up taking longer to recover than the placebo group following the five day treatment period.
Many people complain that zinc lozenges are unpleasant to use due to their poor taste. For what it’s worth, 37% of zinc participants in this study did not complain at all about the lozenges’ taste, or any other adverse effects for that matter. Furthermore, across all participants in the experimental group, the lozenges’ unpleasant taste didn’t result in any meaningful decreases in consumption. These observations led the study’s authors to conclude that most people can stand the taste of zinc lozenges just fine.
“Our study does not confirm the usefulness of zinc lozenges for treating the common cold, but neither does it refute the previous studies where zinc lozenges were found to be effective,” Dr. Harri Hemilä states in a release.
“In future trials of zinc lozenges, the dosage of zinc should be greater, the lozenges should dissolve more slowly, and the treatment should last longer than 5 days. Before zinc lozenges can be widely promoted for common cold treatment, the characteristics of lozenges that are clinically efficacious should be defined in detail,” he explains.
The study is published in BMJ Open.