Vitamin C is best known for strengthening the immune system by supporting and improving white blood cell function. It is also essential for the proper formation of collagen, the building block of many tissues and a crucial component in skin rejuvenation. Vitamin C also helps to reduce histamine release in the body, thereby alleviating allergy symptoms. There are numerous forms of vitamin C with ascorbic acid being the most basic. People wanting a clinically-proven form that is easier on the system than ascorbic acid should choose Ester-C brand calcium ascorbate.