When I was in my mid-20s, I experimented with different health food vitamins, minerals, powders, etc. to see what would get me really horny and help me get big, strong erections.
Nothing I tried was a 100% instant miracle from what I remember. But maca powder seemed to help. I think horny goat weed helped as well.
Of course viagra works, I used it a few times - but I only used it when I was in a toxic relationship and couldn't get past the mental blocks. It works but it made my head feel like there were weird "waves" running through it at times, I can't totally explain the feeling.