The maximum vitamin C you can take is 2000mg per day. Sometimes people take up to 10g day of vitamin C for sometimes unproven health benefits e. g. preventing respiratory infections, viral diseases, progression of cancer or atherosclerosis. Such doses may acidify the urine, cause nausea and diarrhea, interfere with the healthy antioxidant-prooxidant balance in the body and in patients with diseases, e. g. thalassemia or hemochromatosis, promote iron overload. Staying under the maximum does not have bad effects in healthy adults.
Attribution: Avallain