Ascorbic acid (vitamin C) is used to prevent or cure vitamin C deficiency in those who do not acquire enough of the vitamin via their diet. Most people who eat a healthy diet do not require additional ascorbic acid. Scurvy is a disorder caused by a lack of vitamin C. Symptoms include pain when chewing, swallowing, or moving your tongue; weakness in your legs; depression; and problems with memory and coordination. As a supplement, vitamin C helps fight off infection-causing bacteria and viruses, supports the immune system, and may help prevent cancer. It also plays a role in collagen production, which is important for strong teeth and bones. Vitamin C exists in several forms: ascorbate (AHK), dehydroascorbate (DHAA), and polyglutamate derivatives (these are the main sources of vitamin C in foods). Humans can absorb only as much as 3000 mg of vitamin C at one time. The rest is lost through urine. However, studies show that individuals can absorb up to 10 times this amount if they take their supply over a period of time through repeated doses. It is recommended that you take 200 mg per day as a supplement. High doses may cause stomach upset. Vitamin C supplements should never be taken by themselves - they must be combined with a source of iron such as meat, eggs, or plants to avoid poisoning yourself.