Cotinine

Cotinine is a metabolite of nicotine. Cotinine typically remains in the blood between 48 and 96 hours. The level of cotinine in the blood is proportionate to the amount of exposure to tobacco smoke, so it is a valuable indicator of tobacco smoke exposure, including secondary smoke. Women who smoke menthol cigarettes retain cotinine in the blood for a longer period. Race may also play a role, as black people routinely register higher blood cotinine levels than white people. Several variable factors, such as menthol cigarette preference and puff size, suggest that the explanation for this difference may be more complex than gender or race.

Drug tests can detect cotinine in the blood, urine, or saliva.

The word 'cotinine' is an anagram of 'nicotine'.

There is some research being done on the effects of cotinine on memory and cognition. Some studies have suggested that cotinine (as well as nicotine) improves memory and prevents neuron death. For this reason it has been studied for effectiveness in treating schizophrenia, Alzheimer's and Parkinson's diseases. There is research, however, which also suggests that nicotine and cotinine contribute to Alzheimer's disease in other ways which counter and maybe even negate the possible positive effects they might have