l-Lysine

The essential amino acid L-Lysine cannot be synthesized by the body and must be obtained from the diet. It is primarily noted for its importance in helping to reduce the recurrence of herpes simplex virus (HSV) infection, which mainly affects skin and mucous membranes. As HSV requires arginine to replicate, lysine plays an important role in maintaining healthy gum and lip tissue as an arginine antagonist. Lysine competes with arginine for transport into cells and reabsorption in the kidney, increasing arginine excretion. It also stimulates the activity of arginase, an enzyme responsible for arginine breakdown. Studies suggest that supplementation with lysine significantly reduces the frequency of HSV recurrences, including cold sores. In addition, a randomized, placebo-controlled trial indicated that lysine reduced the occurrence, severity and healing time for recurrent infections.