Urinary cotinine is usually detectable for about 2–4 days after a single cigarette. In regular or heavy smokers it can persist about 7–10 days; very heavy or long-term use (or highly sensitive tests) may detect cotinine up to several weeks. Detection time varies with dose, metabolism, hydration, and test sensitivity; nicotine replacement or recent secondhand exposure can also produce positive results.

Cotinine is the main nicotine metabolite measured in urine. Detection varies by exposure and metabolism: single or light use is usually detectable for about two to four days, while regular or heavy smokers may test positive for up to two to three weeks. The only reliable way to be negative is to stop nicotine and allow natural clearance; seek medical support for quitting and timing.

Cotinine tests are quite sensitive. Common immunoassays detect about 10–50 ng/mL in urine, saliva or blood, while laboratory methods (GC‑MS/LC‑MS) can detect as low as ~1 ng/mL or below. Cotinine’s half‑life (~16–20 hours) allows detection of recent smoking for roughly 2–4 days in urine; hair testing reveals longer‑term exposure. Very low passive exposure may yield levels near cutoffs.

Cotinine, nicotine’s main metabolite, has a half‑life around 16–20 hours. After 7 days, occasional or light users often test negative on urine, blood or saliva tests, but regular or heavy smokers may still test positive. Hair tests detect cotinine for months. Metabolism, frequency of use, body fat, kidney/liver function and test sensitivity influence detection. Abstaining as early as possible gives the best chance.

The fastest reliable way to lower cotinine is to stop all nicotine exposure and let your body metabolize it—cotinine’s half‑life is about 16–20 hours, so levels fall over days. Hydration, regular exercise and increased urination can modestly speed elimination, but there’s no guaranteed quick “detox.” Detection windows vary by test and usage. For personalized advice, consult your healthcare professional.

Drinking water helps kidneys and can dilute urine, slightly increasing excretion of cotinine, but it does not rapidly "flush out" cotinine or markedly shorten its biological half-life. Cotinine is cleared over days as the body metabolizes nicotine; stopping nicotine exposure and time are the main factors. Excessive water can only dilute urine tests and may produce invalid samples; it won't reliably remove cotinine faster.