Nicotine quickly enters your bloodstream. Your liver then breaks down nicotine into several byproducts, primarily cotinine. Depending on what you're testing, such as a blood, urine, saliva, or hair ...

Nicotine itself could clear from your body in a few hours, but its byproduct can linger for days or weeks. Most nicotine tests detect cotinine, which can show up in urine, saliva, blood, hair, and ...

Whether you're smoking cigarettes or vaping e-cigarettes, you're ingesting nicotine. Either way, the addictive substance is linked to a host of health issues, and experts say they still don't have a ...