It works equally well on HSV1 and HSV2. These are the dominant strains of the herpes virus. Mistakenly, people often refer to HSV1 as cold sores and HSV2 as genital herpes. However, HSV1 does can show up in the genital area and HSV2 can be found on the lips and other facial areas. HSV1 and HSV2 share about 50% the same DNA. There are many products such as Acyclovir and Valtrex, that are prescribed for both genital herpes and cold sores.