Health Q&A: supplements for colds

Dr Mark Porter / 16 February 2018

Dr Mark Porter answers a reader’s question about the best supplements to help colds.



Q: I am fed up with catching colds - three this winter and I seem to be going down with a fourth. Would supplements help?

A: Vitamin C and the herb Echinacea are two of the most popular supplements and there have been numerous studies into the efficacy of both, with mixed results. A comprehensive review carried out by the evidence based Cochrane Collaboration suggests that vitamin C (in doses of 200mg or more a day) has no protective effect on your chances of catching a cold. 

But there are exceptions to the rule - five of the trials reviewed by Cochrane did show some benefit in people subjected to extreme physical stress (such as marathon runners and cross country skiers).  In this small group taking regular vitamin C halved the chances of catching a cold.

The herb Echinacea is thought to help fight viruses through a combination of direct anti-viral properties and the ability to boost the body’s natural defences by stimulating the immune system.  But, once again, studies suggest it fails to live up to the hype. The best evidence suggests people taking Echinacea will, on average, have cold symptoms for around two days over a four-month period, while a group taking nothing can expect to be sneezing and sniffing for about 12 – 18 hours longer. Not much of an improvement.

You pays your money and takes your choice, but I wouldn’t bother with either Echinacea or vitamin C.  In practice, the best way to avoid the viruses is to steer clear of people who are obviously infected, to avoid touching surfaces touched by lots of others, and to wash your hands frequently as the viruses gain entry through the eyes, nose or mouth via contaminated fingers. 


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