As for the answer to the question on the purpose of the aspirin...Dan Duchaine's Bodyopus book states on page 165, and I quote "Plain old Aspirin has been proven to extend the effects of ephedrine and caffeine". I can personally vouch for aspirin extending the buzz of caffeine and ephedrine, being an ephedrine addict myself. Sorry, but I really don't believe in Yohimbe. I'm just talking out my ass here, but it seems to me like Yohimbe belongs on the supplement junkpile with HMB, Beta Sitosterol, and Dibencozide. I think I'm going to throw some Yohimbe in the mix, just to see what happens. Couldn't hurt...