A cheap and common supplement could shorten the run of your cold virus by up to two days, a new analysis suggests.
Scientists investigated previous data from eight trials involving more than 900 volunteers on whether zinc could alleviate cold symptoms.
The supplement, which is available from supermarkets and costs as little as $5 per bottle, has long been hailed as a 'natural' remedy for colds and coughs by health gurus on social media.
But for the first time, a gold-standard review by experts at the prestigious Cochrane Institute in the UK has given some credence to the supposed benefits.
The review concluded that zinc could shorten a cold by roughly two days, although the evidence supporting this finding was 'weak'.
A cheap and common supplement could help to battle a cold, a study suggests
The experts cautioned, however, that the capsules can also risk a range of side effects - including bowel problems, nausea and an unpleasant taste in the mouth.
Zinc, a mineral found in foods like chickpeas, cashew nuts and some seafood, is essential for healthy DNA, building protein and bolstering the immune system.
Scientists have long suspected that it has infection-fighting benefits, as lab studies have shown it can stop viral cells replicating in the mouth and nose.
This limits the extent to which a virus can spread throughout the body.
Zinc is popular in the US as a supplement to help shorten the duration of a cold. It is sold in popular stores for $12
Dr Daryl Nault, a health sciences professor involved in the review, said: 'While there have been many trials on zinc, the approaches vary, so it is difficult to draw conclusions with certainty.'
However she added that the supplemenet could 'potentially shorten illness by a few days', if individuals are happy to take the risk of 'potential unpleasant side-effects.'
She added: 'The best advice remains to consult your physician if you're feeling unwell and inform them if you use any supplements.'
Dr Susan Wieland, a researcher and senior author of the review, added: 'The evidence on zinc is far from settled: We need more research before we can be confident in its effects.
'Additional studies focusing on the most promising types and doses of zinc products are important to patients and will enable us to understand whether zinc may have a place in treatment of the common cold.'
Zinc products have been marketed as a treatment for the common cold since the 1980s and are particularly popular in the US.
Walgreens has a 'Zinc Cold Therapy' on the shelves for $11.49, while CVS markets a 'Cold Remedy' that contains Zinc for $11.99. Popular supplement firm Nature Made sells 30mg tablets for $5.79.
In the study, scientists also investigated whether zinc could reduce the severity of cold symptoms - but found no 'strong' evidence to support this.
They also reviewed 15 studies on whether zinc could prevent a cold, but found 'no clear evidence' that this was the case.
