Originally Posted by mrsD

There are two main reasons for l-lysine...

1) to prevent or reduce a herpes outbreak or shingles pain

2) to counter the use of high dose arginine (which may activate latent herpes).

Here is some general info on it:
http://en.wikipedia.org/wiki/Lysine

Originally Posted by mrsD

If you had chickenpox as a child, you can have pain, generated by the latent virus. It does not always make vesicles or rash.

I am also of the opinion that herpes can do it too, since they are related.

If the lysine works for you, I'd take that as a sign!

There is a diet to balance arginine/lysine.

http://www.herpes.com/Nutrition.shtml
One wants to keep arginine lower in ratio to lysine if one has a history of any herpes.