I started taking vitamin C when Linus Pauling, a two-time Nobel Prize winner, advocated vitamin C as a means of reducing the incidence of colds. I have found that I get few colds compared to other people. However that is not a very large or scientific sample.
The Linus Pauling Institute at Oregon State University now takes a more moderate view "Regular supplementation with vitamin C (0.25 to 2 g/day) did not reduce the incidence of colds in the general population (23 trials); however, in participants undergoing heavy physical stress (e.g., marathon runners, skiers, or soldiers in subarctic conditions), vitamin C supplementation halved the incidence of colds (5 trials). A benefit of regular vitamin C supplementation was also seen in the duration of colds, with a greater benefit in children than in adults: The pooled effect of vitamin C supplementation was a 14% reduction in cold duration in children and an 8% reduction in adults."
The Mayo Clinic view is consistent "Taking oral vitamin C supplements won't prevent the common cold. However, there's some evidence that when people who regularly take vitamin C supplements get a cold, the illness lasts fewer days and symptoms are less severe. Starting a vitamin C supplement only after you develop a cold is of no help."
The Apollo Vitamin C is a convenient way to get the vitamin. They contain 1000 mg of Vitamin C, 100 mg of Citrus Bioflavonoids, and Rutin in addition. The capsules are the same size as many other supplements. They are easy to swallow. I intend to continue taking my vitamin C using these capsules.