Cutetonic Vitamin C supplements are perfect for complementing a healthy, balanced diet, whilst also supporting immune function. Vitamin C is one of the most widely used supplements with research suggesting that Vitamin C can help to reduce the duration of illness. Use of Vitamin C assists in supporting the immune function. Vitamin C is an antioxidant, and helps to protect cells against free radical damage. As exercise increases free radical production, Vitamin C makes a good choice.