Sneezing? Sniffling? Coughing up a storm?
A new scientific review suggests that taking zinc may help shorten the duration of common cold symptoms by several days.
But the review, published in the Canadian Medical Association Journal, also cautions that users should be aware of possible adverse effects.
To help tackle the question of zinc's efficacy, researchers studied 17 trials that included more than 21,000 participants. Compared to adults taking placebos, those who took oral zinc saw a drop in the duration of their cold symptoms. There was no effect found in children.
"The common cold is a frequent respiratory infection that is generally benign and self-limited. However, colds can lead to substantial morbidity, lost productivity and school [or] work absenteeism resulting in substantial economic burden," Dr. Michelle Science, who works at the Hospital for Sick Children in Toronto and is a co-author of the study, told The Huffington Post in an email. "As such, a treatment that could shorten the duration of cold symptoms would likely be beneficial on an individual and societal level."
In the U.S., more than 60 million cases of the common cold occur each year, resulting in the loss of 22 million days of work annually.
Science said that the new review showed a "relatively minor" reduction in the duration of cold symptoms. But most colds last between one and two weeks, so to many people, even just a few days can make a big difference.
"There are a myriad of over-the-counter medications, as well as herbal and homeopathic remedies, aimed at relieving common cold symptoms ... but there is certainly no gold standard," said Dr. Richard Lebowitz, an associate professor with the Department of Otolaryngology at the NYU School of Medicine who is not associated with the study.
"As with any medication, these cold remedies have potential side effects [that] must be weighed against the potential benefits, which for the most part have not been proven," he continued. "For this reason, many patients choose to just 'wait it out.'"
Indeed, the new review found that adverse effects were common among people taking zinc. They were approximately 65 percent more likely to experience nausea and a bad aftertaste than those taking a placebo.
The authors also caution that the quality of the individual trials studied for the new review varied greatly. Their overall conclusion aligns with a similar literature review by the Cochrane group, which found that zinc can help reduce the duration and severity of the common cold, but that more research is needed before experts can issue a general recommendation regarding its use.
"Although it is possible that oral zinc preparations impact symptoms of the common cold," Science said, "there is currently insufficient evidence to recommend its use in children, and only a weak rationale for use in otherwise healthy adults."