Cotinine

Cotinine is the major proximate metabolite of nicotine and the gold-standard biomarker of tobacco and nicotine exposure, with a long half-life that makes it a stable index of recent use. In athlete monitoring, salivary cotinine provides an objective non-invasive measure of nicotine intake — whether from smoking, smokeless tobacco, or nicotine products increasingly used for purported ergogenic effect — that can compromise cardiovascular and recovery health. Phillips et al. (1999) validated sensitive salivary cotinine quantification as a reliable exposure biomarker.