I have found that L-arginine definitely enables better erections. According to what i have read, it is because it encourages the production of nitric oxide (NO), which leads to better erections.

However...NO also encourages the emergence of herpes outbreaks in those who already have the virus. So I have stopped taking L-arginine, as I don't want to cause cold sore outbreaks. (Lysine helps fight the emergence of herpes...see below for more on this.)

I assume that Viagra is not associated with herpes outbreaks? I understand that it enables better erections by blocking PDE5 inhibitors, which are enemies to NO. So if my non-scientific understanding is correct, herpes outbreaks are more likely to be triggered by a substance that encourages NO production than by a substance that fights NO's enemy (thus allowing more NO to survive).

I have three questions:
1. Is there a natural substance that acts like Viagra and acts as a PDE5 inhibitor?
2. Is there an NO "enabler" like L-arginine that is less likely to cause herpes outbreaks?
3. What is the "best" natural/herbal ED product that does not contain L-arginine?
4. Or is there a verified alternative product that contains just a bit of L-arginine and will not cause herpes outbreaks?

Thanks in advance.