Yes, someone tested out the caffeine soap and blogged the results!
Seems like he felt a bit of a buzz, however whether its caffeine or a bit of the placebo effect, well who can say.
I jumped into the shower and lathered up with the Shower Shock. Now, in addition to containing roughly 2400mg of caffeine, each bar is also heavily loaded with peppermint oil. Not long after lathering up, I got the feeling that not only had I just gone for a brisk stroll in the peppermint rain through the peppermint forest of the children’s board game “Candyland,” but while walking through the forest I had tripped over a peppermint tree root, fell into a peppermint mud puddle, slid down the slopes of peppermint hill through the peppermint grass, and landed in the peppermint pond.
Wanting to give my skin the maximum possible exposure to the beneficial effects of the soap, I soaped myself up and let the lather sit for a few minutes on a few areas of my body, including my big, bald head. I performed the rest of my daily ablutions, dried off, got dressed, and prepared to leave for work. In addition to feeling the effects of the peppermint oil in the soap, I also fancied I felt a bit more alert. Upon arriving in the office at 8:30, I felt perky enough to avoid the coffee maker for about a half-hour, a notable change from my usual habit of making a beeline to the kitchen upon arrival. I still downed most of my usual ration of coffee, but it seemed to me the soap had made a difference, giving me a small–yet significant–start on my daily fix.