 Because herpes simplex virus (HSV) proteins are richer in arginine and poorer in lysine than the cells they infect, lysine supplements have been tried as a treatment.Since the two amino acids are taken up in the intestine, reclaimed in the kidney, and moved into cells by the same amino acid transporters, an abundance of lysine would, in theory, limit the amount of arginine available for viral replication.Clinical studies do not provide good evidence for effectiveness as a prophylactic or in the treatment for HSV outbreaks.