Taking vitamin C might help people who are stressed and in cold weather get over bad colds faster, cutting the time sick by about half, but we're not totally sure because only a few studies have looked at this.

Taking vitamin C pills might make your cold symptoms less severe if you're a healthy person.

Vitamin C helps reduce bad cold symptoms a lot (by about a quarter), but doesn't really help with mild cold symptoms. This is based on studies of over 2700 colds.

Taking vitamin C supplements might cut your chances of getting a cold in half if you're under a lot of physical stress, like running marathons, skiing, or doing tough military training in cold weather.

Taking vitamin C pills cuts your chances of catching a cold in half if you're doing really tough activities like running marathons, skiing, or military training in freezing cold places.

Taking vitamin C pills every day might make your colds less severe, according to some studies that looked at healthy people.