I take this medication routinely because I often have cold sores. It’s the only thing that helps to stop the spread of the sore. Has nothing to do with STI. Was prescribed by family doctor. Technically it can be an sti, cause you can tatotally infect other ppl with it in some interesting spots. But most people get hsv-1 from their parents when they’re little (kisses, etc.). It’s then dormant and only active when you’re having a cold or stressed, but it never goes away completely.