Nicotine, no doubt about it
I'm like nsfisher, but still not all the way off cigs... I'm a guy who used to smoke a pack of camels a day, 30 years of it. After a Long flight, straight for the cigarette as I get off the plane... Buzz and dizzy. If I'm hungry.. Nausea.
I noticed Burley blends seem to satisfy my nicotine cravings the best, so yes, I'd say any blend with a solid amount of burley is going to give you the buzz if you're not a cigarette smoker and you smoke your pipe too fast. I noticed I get the tongue burn smoking too fast trying to get the nicotine craving to go away.
Slow down, sip, or like me, I am timing when I'm on the puter. Wait till the minute changes on the clock, sip a couple of times, pipe down, watch clock, repeat. Stupid.. But it works ;-)