Yes and no.
So in a review of several previous studies about using zinc supplements either to prevent or treat respiratory infections that was just published in BMJ Open, researchers concluded that if used widely, zinc supplements could reduce respiratory infections in the population at large at the rate of 5 fewer infections for every “100 person-months of oral or intranasal zinc treatment”, and that of taken once a respiratory infection had set in, “treatment with sublingual or intranasal zinc preparations reduced symptom duration by an average of 2 days relative to placebo.”
So how good is that?
First, I have to mention right off the top that the authors of this study thought that the zinc studies they analyzed were not that great, meaning that the evidence for this is slight positive data is less than stellar.
As to the conclusions, it certainly looks good to reduce the number of infections – colds and flu (although not SARS-CoV-2) – you might get this winter but you have to remember that that means taking zinc lozenges throughout cold and flu season, so roughly from October to at least the end of February.
And you would get that benefit only if you were one of the lucky ones cuz the great majority of people would still get sick with a cold or the flu if zinc is what they were relying on for prevention.
The other part of the finding – 2 fewer days with symptoms – is probably a lot more palatable for most people but enthusiasm will likely be tempered for the great majority in discovering that zinc did not reduce the severity of the respiratory infection.
In other words, even if you take zinc, you will still feel as miserable as you always do, although the mild symptoms towards the end of the infection might feel better.
On top of those hesitations, you have to add into the equation that zinc can cause lots of side effects, particularly nausea and other GI symptoms, so all in all, not a great recommendation, if you ask me.