As we talked about recently there is L-Lysine. The idea is that by raising Lysine levels you are effectively lowering Arginine, which is thought to increase outbreaks, so by keeping it low you will reduce OB's. Some say it helps, some say it doesn't. There are a few positive studies but most are from the late 70's or early 80's. I wasn't able to find anything recent that had real positive results. So many different opinions about this, best really to google it yourself and see what you think.