I just wanted to add that Lysine metabolism is connected to Vitamin C, so it's advisable to take a little Ascorbic Acid with Lysine, if taken as a supplement.
Vitamin B6 is also keeping Herpes at bay. My wife used to have Herpes Labialis regularly, until i recommended her to take B-Vitamins (in 1-2x RDA amounts), as well as B6 as high as 10mg per day. Blisters are very rare now, and a good dose of Lysin+C for three or four days acts as a first aid to let them heal quicker and stop them from spreading.