The Common Cold and Vitamin C - To Take or Not to Take?

Does vitamin C supplementation improve immune function, including preventing or treating the common cold?

  • Habitual vitamin C supplementation may reduce cold severity and duration, pneumonia incidence and exercise-induced bronchoconstriction symptoms. For the general population, it does not reduce cold incidence or improve asthma outcomes, but an exception may be decreased cold incidence in individuals undergoing brief periods of heavy physical stress (soldiers and athletes).
  • Treatment with vitamin C after the onset of symptoms does not reduce cold severity or duration and does not improve acute pancreatitis outcomes but may reduce pneumonia severity and hospital length of stay in individuals with low plasma vitamin C.
  • Vitamin C supplements of ≤2 g/day have not been associated with adverse effects, except in individuals with severe acute pancreatitis.