In the study, 1, patients were treated for a cold sore outbreak. The participants got one of three treatments: twice-daily Valtrex for one day. For recurrent outbreaks of genital herpes, valacyclovir works best if it is used within 24 hours after the symptoms begin to appear. For treatment of cold sores . The recommended dosage of VALTREX for treatment of cold sores is 2 grams twice daily for 1 day taken 12 hours apart. Therapy should be initiated at the.