Doesn vitamin C cause diarrhea in large doses?
Yes, in very large doses some of the vitamin C that you take will not be absorbed, and if enough is left in the bowel it will draw water and lead to loose bowels at first, and diarrhea with higher doses. You usually have to take over 8 to 10 thousand milligrams of vitamin C to get this effect, although some people can take up to 25 thousand mg without a problem. Higher doses are more tolerable when you have any kind of illness, particularly a virus or other infection. Occasionally people have problems with smaller doses, but it is unusual. It does not really matter which form of vitamin C you take as a dietary supplement, and the effect is harmless if you recognize it and slightly reduce your dose. Some practitioners suggest finding out how much it takes to cause loose bowels, and then to take slightly less than that amount. They call this the “bowel tolerance” level.
