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How long before Nicotine is out of system?
An_240820 posted:
Can anyone (preferably a professional) tell me about how long it takes for Nicotine to clear out of the body? I am looking to apply for a job and they will not hire smokers. I am also tired of smoking and need to quit, so this will give me added incentive....
Jonathan Foulds, PhD responded:
Nicotine has a half-life in the human body of 2 hours (although it can range from 1 to 4 hours in different individuals). The average smoker has a blood nicotine concentration of about 40 ng/ml after an evening cigarette. But lets take the example of a very heavy smoker who smokes their last cigarette at the stroke of midnight and has a nicotine level of 80 ng/ml. By 2am it will be 40 ng/ml. by 4am, 20 ng/ml, 6am, 10 ng/ml, 8am 5 ng/ml, 10 am, 2.5 ng/ml, 12 noon, 1.25 ng/ml. So within 12 hours it is almost gone, and so certainly by 24 hrs it is all gone.
UncleB42 responded:
I hold a Masters Degree in Counseling Psychology and was trained at Hazelden and Mayo Clinic for drug/alcohol and tobacco addiction.
The answer to your question is three days for approximately 95% of all nicotine and including residual nicotine and continine and interstitial.
Barry McMillen, MA, LADC, CTAS
Jonathan Foulds, PhD replied to UncleB42's response:
Sorry to split hairs on this, but given that the typical half-life of nicotine is 2 hours, and that most assays have a limit of detection of 0.1 to 0.5 ng/ml, following the logic I described above, all the nicotine has gone from the blood stream within 24 hours. i.e. when you take a blood sample from a smoker 24 hours after their last smoke, they will most likely have a blood nicotine level <0.5 ng/ml. (i.e.>95% gone by 24 hrs). Cotinine (the main metabolite) has a half life around 20 hours and so takes days to a week to disappear. But cotinine is an inactive metabolite that is not believed to have a meaningful role in nicotine dependence.
Jonathan Foulds, PhD replied to Jonathan Foulds, PhD's response:
So if you are applying for a job that will not hire smokers, they may well test for cotinine. Given its longer half-life, and the individual differences in metabolism, I would say you need to quit for over a week, without any nicotine replacement, to be confident of having a low enough level of cotinine. If you can do that then of course you may as well stay quit.
UncleB42 replied to Jonathan Foulds, PhD's response:
As long as you are splitting hairs, the question reads body not blood. You stand corrected, sorry about that, you are correct about the blood though. Nicotine is found in many places in the body besides just the blood, Jonathan, as Ach receptors proliferate the body and not just the brain.
Devylann replied to Jonathan Foulds, PhD's response:
well, i have smoked for over 10years,heavily at first then for the passed year, i've decreased the amount to 3 a week. i was up for a health exam for life insurance and i stopped smoking for 7 days. the test came back positive for nicotine in the blood. why is that when you said that within 24 hours it should be gone within the last cigarette?
Jonathan Foulds, PhD replied to Devylann's response:
Most likely they didn't test for nicotine, but cotinine (the main nicotine metabolite). Cotinine has a half-life about 10 times longer than nicotine, so may still be detectable at elevated levels for up to a week. All this depends on individual factors...e.g. how fast they metabolize nicotine.
daniegirl1030 replied to Jonathan Foulds, PhD's response:
Maybe you could help me with my question. I recently got hired for a job and had to undergo cotinine testing, however because I drank a lot of water, the lab requested a second test due to dilution. Before my first testing, I had been smoke free for 3 days. I took the test, then ignorantly lit a cigarette, it tasted awful.. I probably took 2 or 3 puffs off of it before throwing it out. I got a call 2 days later to come back in for a second urine test. So, at the time of my 2nd urine test, I had been almost 100% smoke free for 6 days, minus the 2 or 3 puffs. Is it possible that my urine will test positive for cotinine?
SOTO5150 replied to daniegirl1030's response:
Jonathan Foulds,
I could also use the help I have to take a saliva test i need to know how long and is there anything i can do to help process along?
mamainindiana replied to Jonathan Foulds, PhD's response:
Recently my company has started a wellness program. In 9 days I have a test. We were given warning and based on the prices I have decided I wanted to quit.l

Prior to yesterday I have been smokefree with no replacements of nicotine for 13 days.

I had a stressful evening and like an idiot I smoke about 8 cigarettes.

I was curious given that I was doing well and now I still have 9 days should I be okay to make the < 20ng/l cotinine levels

bc2000 replied to mamainindiana's response:
A few more questions:
1. What about second hand smoke? I have stopped smoking but my wife still smokes. I am not in the room while she has a morning cigarette, and she runs an exhaust fan, when I come back in only a slight smell is left. Can this cause a problem?
2. I ordered NicAlert saliva test, how accurate are these?
3. Had my last cigarette Monday morning, Tuesday lightly puffed a Logic e-cig, suppose to be .01 nicotine, Thursday evening I tried the NicAlert, and it still said I was a smoker. So does that mean I would still fail the company test?
4. I called a health store that I won't name, that said they do have something that will "mask" the signs of nicotine for testing, does that type of stuff really work OR will that just show up as something else and just cause me more problems?

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