L-Lysine monohydrochloride is a widely used dietary supplement form of the essential amino acid L-lysine, essential for protein synthesis, tissue repair, and immune system function. Common uses include preventing and treating herpes/cold sores, reducing anxiety, supporting collagen formation for bone health, and improving muscle recovery. Patsnap Synapse +2Key Uses and Benefits of L-Lysine MonohydrochlorideCold Sore and Herpes Management: L-lysine helps manage herpes simplex virus (HSV) infections by inhibiting the activity of arginine, an amino acid that supports virus replication.Anxiety and Stress Reduction:.Nutritional Support: Used in supplements and food fortification, particularly in areas where diet lacks sufficient lysine.Animal Health: Frequently used as an essential amino acid supplement in poultry and animal feed