Vitamin C is one of the first vitamins people think of when interested in the topic, and for good reason. A staple antioxidant, Vitamin C is very valuable for helping the body to neutralize free radicals that contribute to oxidative stress. Lysine is similarly prized for its ability to help the body balance excess arginine. Too much arginine can negatively impact your body's immune reaction. While these supplements are available from food in a healthy diet, they are well supported in higher quantities and can help play a part in sustained, optimum health.