How Long Does It Take for Nicotine to Leave Your System?

By Terez Malka, MD
Medically reviewed checkmarkMedically reviewed
November 1, 2021

Nicotine is the substance found in tobacco products that causes addiction, serious health conditions, and premature death.

Tobacco use is the leading cause of preventable death in the United States.

People who use or inhale it regularly, whether directly or through secondhand smoke, run the risk of developing several forms of cancer, cardiovascular disease, emphysema, stroke, acute respiratory illnesses, and other disorders.

In this article, I’ll explain how long nicotine stays in your system—in your blood, urine, saliva, and hair follicles.

I’ll talk about smoking versus vaping, and factors that determine the amount of nicotine going into your body.

I’ll discuss some ways to clear nicotine from your body, and outline some withdrawal symptoms people experience when they quit

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How Long Does Nicotine Stay In Your Blood?

About 90 percent of the nicotine inhaled into your blood enters your bloodstream, and begins to enter your blood almost instantly when you light up.

Most of the nicotine leaves your blood in a few hours, but some amounts can remain for up to three days.

Nicotine use can also be detected for much longer: Cotinine, a chemical formed when nicotine is being broken down in the body, is what lab technicians look for when testing if there’s nicotine in the blood.

And cotinine can remain detectable  in the blood for up 1-10 days after nicotine enters the bloodstream.

The timeline also depends on how much nicotine was inhaled as well as your genetics. 

There are two ways to test for nicotine or cotinine in your blood: qualitative (determines if nicotine is present or not) and quantitative (determines the amount of nicotine present).

Quantitative testing can determine if you are an active smoker or if you have recently quit. In the event you are not a smoker, the test can determine if you are breathing in a lot of secondhand smoke.

When it comes to blood tests, it is possible to have a false positive when a compound called thiocyanate, which is found in broccoli, garlic, cabbage, and specific medications, is present in your blood.

You may also test positive even if you are not a smoker, but are exposed frequently to secondhand smoke. 

How Long Does Nicotine Stay In Your Urine?

Nicotine and cotinine will be detectable in your urine for up to four days.

However, this will depend on how regularly you smoke and how much. If you are a frequent smoker, cotinine may be detectable in urine for up to three weeks after your last exposure.

It also may take longer for cotinine to leave your urine if you’re a nonsmoker who has been exposed to a high concentration of secondhand smoke: Studies have found that smokers more efficiently clear this chemical from their symptoms.

It is important to note that cotinine concentrations are 4-6 times higher in urine than in blood or saliva. 

How Long Does Nicotine Stay In Your Saliva and Hair Follicles?

Nicotine and cotinine remain detectable in your saliva for about as long as it does in your blood—up to four days.

But it can be detected in your hair follicles for much longer.

It can take up to three months, and in some cases, even a year, for all traces of nicotine to be eliminated from your hair follicles.

While hair testing is possible, it is not as commonly used because it costs more than urine, saliva, and blood testing.

Smoking vs. Vaping

E-cigarettes, also known as vapes, are battery-powered electronic cigarette devices that contain nicotine and other chemicals that can be harmful to your health.

Using one of these electronic cigarettes is commonly called “vaping.”

The fundamental difference between smoking and vaping is that smoking works by burning tobacco and vaping works by heating a liquid.

Smoking can lead to smoking-related illnesses, making them more harmful than vapes, but vaping still contains harmful chemicals such as nicotine, and can cause severe lung disease in some, especially teens. 

E-cigarettes are very addictive, and may contain even higher levels of nicotine than cigarettes.

Just like cigarette smoking, vaping raises your blood pressure and spikes your adrenaline.

This can greatly increase your heart rate and the likelihood of having a heart attack.

Factors That Determine Nicotine Amount


How frequently you smoke will determine how long nicotine can be detected in your system.

Light smokers, defined as those who smoke once or twice a week, will flush out nicotine faster than heavy smokers who consume nicotine every day.

Nicotine may be detectable in heavy smokers up to a year after their last exposure.


Medications that affect your metabolism can also be a factor in how fast nicotine is processed by the body. Phenobarbital (Luminal) and certain antibiotics speed up the metabolism of nicotine.

Other medications, including some antifungal and hypertension medicines, can slow down the metabolism.


Since nicotine is predominantly metabolized by the liver, more nicotine is metabolized when there’s more blood flowing to the liver—especially around meal times.

For the 30 to 40 minutes after a meal, your body clears more nicotine.

Grapefruit juice has also been found to clear nicotine from your system more quickly—though scientists aren’t sure why.


Age can play a key role in the metabolization of nicotine.

Scientists believe this is related to less blood flow to the liver, which decreases as we age.

How to Clear Nicotine From Your Body

The best way to clear nicotine from your body is to cease smoking at least 10 days before your test.

If you are looking to flush nicotine from your body more quickly, here are a few tips that may help speed up the process:

  • Drink plenty of water: This will help flush waste products from the kidneys and liver.
  • Increase your exercise: This will help get the blood circulating to your liver, and will release waste products through sweat.
  • Boost your antioxidants: Antioxidants help the body repair itself. Consider increasing your daily intake of foods rich in antioxidants or adding in a multivitamin.

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Nicotine Withdrawal Symptoms

Nicotine withdrawal is a challenging experience for almost all smokers who have made the decision to quit.

As nicotine leaves the body, withdrawal symptoms will start to manifest, reaching their peak at about 72 hours and easing in the subsequent 3-4 weeks.

Below are common symptoms associated with nicotine withdrawal.



  • Anxiety
  • Depression
  • Being easily irritated, angry or frustrated
  • Poor Concentration
  • Restlessness 
  • Nightmares 

How K Health Can Help

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K Health’s AI-powered app is based on 20 years of clinical data.

Frequently Asked Questions

How can you detox your body from nicotine?
The only way to truly detoxify your body is to stop using or inhaling nicotine and allow time to clear it from your body. Supporting your overall health can help your body clear toxins: Drink plenty of water, exercise regularly, and consume a healthy diet with antioxidant-containing foods.
Can healthcare providers tell if you smoke from a blood test?
Yes. Providers can tell whether you smoke through tests of your blood, urine, saliva, or hair. If you are exposed to secondhand smoke, you may also test positive.
How long does it take for your lungs to fully recover from smoking?
It can take up to nine months for your lungs to repair themselves from smoking, and in some cases, the damage is permanent. You will see lung improvement in as little as two weeks after last exposure. After 15 years of quitting cigarettes, your risk of coronary heart disease is comparable to a non-smoker.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

Terez Malka, MD

Dr. Terez Malka is a board-certified pediatrician and emergency medicine physician.