I have a high nicotine liquid by Totally Wicked called Green Cow. It has caffeine in it, and the throat is painful. The caffeine definitely does something. I also have some 0-nic sample liquids, and my bf buys pharmaceutical grade Caffeine Anhydrous off of eBay to use before his gym workouts. If I can find info on whether it's safe or not to try vaping the powder, I'll go ahead and mix some of it with my 0-nic eliquids and report back here with my findings.
As for the chili peppers, Totally Wicked has some Decadent Vapor flavors - 2 of them, I think - that contain peppers. Diablo Loco and Diablo Poco now that I've checked on them. I'm sure it's just pepper oil, but there it is, if anyone wanted to try them out. I'm not trying the peppers myself
I'll be back with data on the caffeine, if I have the guts to try it
EDIT: Found enough info to make me try it. I'll add some powder to my 0-nic liquid right now and give it a whirl. Here's some of what I googled:
"Caffeine readily sublimates with minimal degradation, making it almost ideal for heating and inhalation. I am rather addicted to caffeine (I eat about 250mg-400mg a day).
Thus I put about 50mg of caffeine into a piece of foil and used a borosilicate glass tube to inhale. The caffeine vapour is hard to describe but somewhere in between oak and plastic. Being that it sublimes around 80-90C, the sublimated caffeine is very smooth and not uncomfortable to the lungs in any way. The caffeine recrystallizes very quickly upon cooling with a nice crackling sound, and leaves no residue when completely evaporated.
The result was the usual caffeine stimulation within about 2-4 seconds after inhaling. I felt alright after the first hit, but found myself wanting more so I took another couple. Within seconds it was like that feeling an hour and half into a strong cup of coffee. Lots of stimulation and a bit twitchy. Not unpleasant, though."
Here goes nothing...