What is Cotinine?
When nicotine enters the body, the liver metabolizes roughly 70–80% of it into cotinine. Cotinine has a half-life of approximately 16 hours — much longer than nicotine's 2-hour half-life — making it a reliable marker for nicotine exposure over the preceding 2–3 days. Cotinine is measured in blood, urine, or saliva samples and is used in clinical settings to verify smoking status, assess cessation progress, and screen for secondhand smoke exposure. Levels are generally categorized as: non-smoker (< 1 ng/mL in serum), secondhand smoke exposure (1–10 ng/mL), and active smoker (> 10 ng/mL, often 100–300+ ng/mL for regular smokers). Cotinine levels decrease significantly within days of reducing cigarette intake.
- Half-life: ~16 hours (vs. nicotine's ~2 hours)
- Measurable in blood, urine, or saliva
- Detects smoking over the past 2–3 days
- Used in insurance, clinical trials, and workplace testing
- Levels begin dropping within 24–48 hours of reducing cigarettes
How SmokeClock helps with Cotinine
As you reduce your cigarette count with SmokeClock, your cotinine levels will drop in proportion to your reduced nicotine intake. This measurable decline reflects real progress in lowering nicotine dependence — even before you reach zero cigarettes. If you are subject to cotinine testing, gradual reduction can help lower levels more systematically than abrupt cessation attempts that often end in relapse.
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