Nicotine itself typically stays in your system for about 1 to 3 days after the last exposure, as it is rapidly metabolized and cleared from the bloodstream with a half-life of around 2 hours

. However, nicotine breaks down into metabolites, primarily cotinine, which remain detectable for a longer period. Cotinine, the main metabolite of nicotine, can be detected in various body fluids and tissues for different lengths of time:

• Blood: Cotinine can be detected for up to about 10 days after nicotine use, while nicotine itself is usually detectable for only 1 to 3 days

• Urine: Nicotine can be found for about 3 to 4 days, but cotinine may be detectable for up to 2 weeks or sometimes longer depending on factors like frequency of use and individual metabolism

• Saliva: Cotinine can be detected for up to 4 days after the last use

• Hair: Nicotine and cotinine can be detected for 1 to 3 months or even longer, reflecting long-term exposure

The exact duration depends on several factors including how much and how often nicotine was consumed, the method of intake (smoking, vaping, chewing), individual metabolism, genetics, and exposure to secondhand smoke

. In summary, while nicotine itself clears from the blood within a few days, its metabolite cotinine can be detected for up to 10 days in blood and saliva, and up to two weeks or more in urine. Hair tests can reveal nicotine use for months after cessation. This makes cotinine the preferred marker for nicotine exposure in most tests