Nicotine itself usually stays in the body for a short time. In many adults, it has a half-life of about 2 hours, which means the amount in the blood drops fairly quickly after smoking, vaping, chewing tobacco, or using nicotine replacement products.
However, nicotine is broken down into cotinine, a substance that lasts longer and is often what tests look for. Cotinine can remain detectable for several days, especially in urine, saliva, or blood. For many people, urine or saliva tests may stay positive for about 2 to 5 days after the last use, depending on how much nicotine was used and how often.
The exact time can vary from person to person. Heavy or frequent nicotine use, slower metabolism, genetics, kidney function, and the type of test used can all affect how long it shows up. Hair testing may detect nicotine exposure for much longer, sometimes up to around 3 months.
For anyone trying to quit nicotine, support from a primary care doctor, lung specialist, or smoking cessation program can make quitting safer and more manageable.