How Long Does Cotinine Stay in the Blood System?

Cotinine is a chemical created by nicotine breakdown in the body. Doctors use cotinine blood tests to check the urine of people who smoke cigarettes or engage in passive smoking and assess their exposure to environmental tobacco smoke.

As cotinine has a longer half-life than nicotine, it remains in the body for longer. According to Mayo Clinic, the half-life of cotinine is about 16 to 20 hours. This means that it usually takes 2 to 3 days for the cotinine level in your blood to drop by half following exposure.

Time Since Last Cigarette Use	Cotinine Concentration
8 hours	50%
24 hours	33.3%
72 hours	12.5%
5 days	1.6%
2 weeks	0.1%

Extended Detection Window

The length of time cotinine can be detected in the blood varies depending on several factors, including:

Frequency and intensity of smoking: The more a person smokes, the higher their blood and urine cotinine levels will be. According to a study by the Centers for Disease Control and Prevention (CDC), smokers with more than 30 cigarettes daily have cotinine levels that are 10 to 18 times higher than nonsmokers.

Age and Nicotine Metabolism: Cotinine clearance is slower in older adults, and females have higher cotinine levels than males.

Metabolism and Body Fat: Cotinine is stored in body fat, so people with a higher percentage of body fat may have detectable cotinine levels for a longer duration.

Genetics: Some individuals may metabolize nicotine differently, which can affect cotinine levels.

Cotinine Concentration	Detection Window
>1 ng/mL	24-48 hours
>5 ng/mL	3-4 days
>10 ng/mL	5-7 days
>20 ng/mL	7-10 days

Success Stories

A 55-year-old female smoker with a 30-pack-year history quit smoking and had a cotinine level of 2.5 ng/mL after 6 months.

A 25-year-old male social smoker with a 5-pack-year history had a cotinine level of 1.2 ng/mL after 2 weeks of quitting.

A 16-year-old female who was exposed to secondhand smoke at home had a cotinine level of 0.8 ng/mL after her parents quit smoking.

FAQs

1. How long does cotinine stay in the urine?

Cotinine can be detected in urine for up to several weeks after exposure.

2. Does vaping produce cotinine?

Yes, vaping produces cotinine, but the levels are typically lower than in cigarette smokers.

3. What are the health effects of cotinine?

Cotinine itself is not harmful, but it is a marker for nicotine exposure, which is associated with various health issues.

How Long Does Cotinine Stay in the Blood System?