When im feeling a cold sore coming, is it ok to take lysine supplement with my emergency dose of valtrex( 8 pillsx 2times-12 hours )...?

ABSOLUTELY!!: I think L-lysine is a very effective anti-viral supplement and you should start taking it the minute you feel a tingle of an outbreak, or whenever your immune system is knocked down, like with a cold or extreme stress. Only use it for 7-10 day periods, however, because you can down-regulate your immune system with constant use.

It's just fine: It is just fine to take lysine with Valtrex (valacyclovir) and daily lysine can help prevent outbreaks.