It’s long been thought vitamin C is the cure for the common cold or at least something that will help the symptoms. A Cochrane systematic review published in 2013 looked at 29 studies on developing a cold while taking a vitamin C supplement regularly. It was found that this is only really beneficial for those participating in high level sports but not the average Joe like you and me. There was an overall failure to see a reduction in the incidence of common colds in the general population and supplementation only reduced the symptoms of the cold by 8%. When this has been tested again these results were not replicated.⠀
Research on zinc
Zinc however, well there is some promising research on this micronutrient.⠀
A meta-analysis conducted by Rondanelli et al (2018) where they looked at 82 research studies found that zinc supplementation can reduce the duration of the common cold by 33% however it must be taken within the first 24 hours of the onset of symptoms. And as for the dosage well that’s a little bit tougher to decipher and there are no formal recommendations. This is also where it becomes tricky because you may not know exactly when that 24 hour period starts. In another review conducted by Harri Hemila in 2011 it was found that a daily supplement of more the 75mg/day was also associated with a reduction in duration but any less and the results weren’t seen.⠀
It’s also important to note these studies and another systematic review by Singh and Das in 2015 reported a reduction of duration but not how bad the symptoms are. The common cold on average lasts around 10 days so if you can get it early you could reduce its length by about 3 of those days.⠀
And finally it seems zinc acetate lozenges are best for the above. The challenge is finding one with an adequate dosage, which to be fair is difficult given there is uncertainty around how much will be of benefit. Many zinc lozenges come with added vitamin C which is totally fine, check the mg content per lozenge and aim for around 75mg/day for the duration of the cold. This is likely to be more than what’s in one or two lozenges. Do be mindful there could be side effects including a bad taste and nausea and if you experience these then dosage should be dropped or stopped.
You cannot avoid it completely, if you catch the bug you’ve gotta ride it out, just perhaps not for as long.