Vitamin C is a water-soluble nutrient well known for its vital role in the immune system. Vitamin C is also necessary for the production of collagen (a structural protein in connective tissue) and is therefore important for skin, bone, and joint health. Vitamin C is needed for amino acid metabolism, neurotransmitter synthesis, and the utilization of many nutrients, such as folic acid and iron. It is also a highly effective antioxidant that can protect the body's cells and molecules from damage by free radicals and reactive oxygen molecules generated during normal metabolism and exposure to environmental stressors.