Vitamin C is beneficial in many different ways. A few of the benefits are that it increases collagen production (which is important to maintain healthy bones, blood vessels, and skin), aides in the absorption of iron when taken orally, helps with cholesterol control, helps improve adrenal gland function which leads to improved energy, and can shorten the duration of viral illnesses.
So why give it in an IV? Under normal conditions, your GI system can only absorb and use a limited amount of vitamin C per day. The rest escapes through the urine.
The IV route bypasses the GI tract, enabling the body to take in the higher doses necessary to help fight certain problems such as fatigue, infections, and even cancer (when used in conjunction with cancer therapies) effectively.
IV vitamin C has been shown to help boost the immune system, combat free radicals, improve the appearance of skin, strengthen cardiovascular health, and even actively help the body fight off viral infections such as the flu or the common cold.
Laboratory studies have shown that higher doses turn IV vitamin C into a pro-oxidant which may be able to slow the growth of cancerous cells (prostate, pancreatic, liver, colon, etc.). This protocol can be used in conjunction with traditional treatment like chemotherapy and radiation. Some studies have also shown that concurrent IV vitamin C infusions at these doses can make chemotherapy more effective and help improve treatment related side effects. However, each person can have different effects with this treatment. Furthermore, the levels of some classes of chemotherapeutic medications can be affected as well.