There have been a lot of discussions since a study in the 1980s came out concerning the use of zinc as a supplement to prevent or even lessen the duration of the common cold. Since then, more studies have come out, but the results haven’t exactly been conclusive.
The cold is the most common illness in our country, most often caused by the rhinovirus. The highest number of colds occur in the winter time, which has caused a considerable amount of confusion in the general public. We’ve all been given advice as kids about the dangers of wet hair and cold weather, but neither of those things actually increases your chance to get a cold. The most likely reason why your chances of getting a cold increase in the winter time is because people are often forced to stay indoors. During the winter the heat is typically running which tends to dry out the air in your home, business, or school, which also dries out the nasal passages. When you combine these things together, it’s much easier to transmit viruses.
A study in 2013 looked at the available research up to that point on zinc and the common cold. They found that taking zinc was associated with a shorter duration of cold symptoms (about 1 day) but it didn’t have any effect on the severity of the symptoms. Participants in the zinc group were less likely to develop a cold, miss school, or take prescription antibiotics.
An article in TIME in 2017 looked at an article that claimed zinc lozenges might triple the rate of recovery for the common cold. As they point out in the article, the participants in the studies were given doses much higher than those recommended commonly by doctors.
While there may be some benefits to taking zinc at the first signs of a cold, there are some side effects as well. The most common side-effect by far appears to be nausea. As someone who has taken zinc lozenges, I can attest to this. The other two forms people usually use to supplement zinc is through syrup and nasal sprays. The FDA actually put out a warning regarding the nasal sprays because there were more than 100 cases of loss of smell linked to the sprays. Taking large amounts of zinc can also lead to copper deficiencies in the body.
The research seems fairly strong that if you take zinc within 24 hours of the first indications of a cold, there’s a pretty good chance you’ll shorten the total duration. Unfortunately, there hasn’t been enough research on adequate dosing recommendations to confidently produce a consistent result across different populations of people. If you do a simple risk/reward analysis and decide it’s worth it to shorten your cold duration by about a day - I would recommend discussing adequate dosage recommendations with your family physician. Otherwise, waiting it out with some chicken soup and adequate rest might still be the best option.