What Supplements Can Fight Colds?

What Supplements Can Fight Colds

It’s that time of year. Colds are going around. With the holidays picking up we’re going to be susceptible to more of them as we gather for events, get even less sleep, and travel in airplanes, on ferries, etc. Last week I was inspired by some clients to check into what the scientific literature says about supplements and the prevention and treatment of colds. Here’s what I found out about a number of commonly used remedies. An important note is that these results and advice are for adults. Often there isn’t enough evidence regarding effectiveness and safety for kids.

Vitamin C

Taking vitamin C daily doesn’t likely reduce the risk of getting a cold for most people. But there is evidence that athletes (i.e. those experiencing extreme physical stress) may get fewer colds. I don’t know about you but I would call lack of sleep and/or travelling to be “extreme physical stress”. As such, I think that taking some extra vitamin C during these times may help reduce the chances of getting a cold. If you do get a cold, taking 200mg or more of vitamin C may reduce how long your cold lasts.


Zinc lozenges likely help reduce the length of a cold. Take 75mg or more of zinc via lozenges starting within 24 hours of your cold symptoms and continue to take them until you feel better. Don’t take high doses of zinc long-term. There isn’t evidence that zinc helps to prevent colds. And, high doses of zinc can interrupt the absorption of other important nutrients.


Taking North American ginseng once you feel a cold coming on may decrease the length of time that your cold lasts. Taking ginseng doesn’t seem to reduce the risk of getting sick.


Taking probiotics strengthens the immune system and can decrease the length of time that you’re sick.

Other Supplements Can Fight Colds

The scientific evidence isn’t supportive for the following. This doesn’t necessarily mean that they don’t work. It may mean that there haven’t been enough studies done, that there are problems with the design of studies, or that there are so many types of a supplement that we can’t make a clear decision based on the studies done to date.

  • Echinacea purpurea
  • Garlic