Is valtrex (valacyclovir) or zovirax better for cold sores?

Either: I'm assuming you're talking about oral Valtrex (valacyclovir) and zovirax (not zovirax cream). Both are effective, but Valtrex (valacyclovir) is more convenient, because it doesn't have to be taken as frequently. My favorite way to treat cold sores is to have the patient take 2 grams of Valtrex (valacyclovir) at the very first sign of an outbreak, and then 2 grams 12 hours later. That two-dose course will shorten the duration of infection.