Nicotine has a half-life of about two hours and can stay in the blood for about one to three days. Cotinine, a byproduct of nicotine, has a half-life of 18 hours and can last for several days.

Nicotine's immediate effects on the body include decreased appetite, heightened mood, increased heart rate and blood pressure, nausea, diarrhea, and increased alertness. In the long term, however, ...