Vitamin C is responsible for many functions in the human body and is involved in the process of collagen synthesis, tissue growth and repair and wound healing, in the production of antibodies and stimulation of white blood cells, in the absorption of iron and its necessary accumulation in the bone marrow, the spleen and liver and acts as an antioxidant nutrient. Vitamin C lasts a few hours in the bloodstream, so it's best to take it in small doses throughout the day. In addition, it effectively neutralizes free radicals, which are destructive, high-activity molecules that are believed to be the basis of many serious diseases, including cancer and heart disease.