High dose vitamin C therapy can help boost your immune system, speed recovery, fight illness and disease, reduce inflammation, and improve your quality of life. Vitamin C is a powerful antioxidant that protects against heart disease, decreases cholesterol, aids in iron absorption, and protects you against a variety of cancers. It can also improve malaise, fatigue, and depression, and can help reduce the symptoms of chronic fatigue, and some autoimmune infections.