Evaluation of toxicant and carcinogen metabolites in the urine of e-cigarette users versus cigarette smokers

Nicotine Tob Res. 2015 Jun;17(6):704-9. doi: 10.1093/ntr/ntu218. Epub 2014 Oct 21.


Introduction: Electronic cigarettes (e-cigarettes) are rapidly increasing in popularity but little information is available on their potential toxic or carcinogenic effects.

Methods: Twenty-eight e-cigarette smokers who had not smoked tobacco cigarettes for at least 2 months provided urine samples which were analyzed by validated methods for a suite of toxicant and carcinogen metabolites including 1-hydroxypyrene (1-HOP), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), 3-hydroxypropylmercapturic acid (3-HPMA), 2-hydroxypropylmercapturic acid (2-HPMA), 3-hydroxy-1-methylpropylmercapturic acid (HMPMA), S-phenylmercapturic acid (SPMA), nicotine, and cotinine. Levels of these compounds were compared to those found in cigarette smokers from three previous studies.

Results: Levels of 1-HOP, total NNAL, 3-HPMA, 2-HPMA, HMPMA, and SPMA were significantly lower in the urine of e-cigarette users compared to cigarette smokers. Levels of nicotine and cotinine were significantly lower in e-cigarette users compared to cigarette smokers in one study but not in another.

Conclusions: With respect to the compounds analyzed here, e-cigarettes have a more favorable toxicity profile than tobacco cigarettes.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetylcysteine / analogs & derivatives
  • Acetylcysteine / urine
  • Adult
  • Carcinogens / analysis*
  • Cotinine / urine
  • Electronic Nicotine Delivery Systems*
  • Female
  • Hazardous Substances / urine*
  • Humans
  • Male
  • Middle Aged
  • Nicotine / urine
  • Nitrosamines / urine
  • Pyrenes / urine
  • Pyridines / urine
  • Smoking / urine*
  • Tobacco Products*
  • Young Adult


  • 3-hydroxy-1-methylpropylmercapturic acid
  • Carcinogens
  • Hazardous Substances
  • Nitrosamines
  • Pyrenes
  • Pyridines
  • S-phenyl-N-acetylcysteine
  • Nicotine
  • S-(3-hydroxypropyl)cysteine N-acetate
  • 4-(methylnitrosamino)-1-(3-pyridyl)-1-butan-1-ol
  • Cotinine
  • 1-hydroxypyrene
  • Acetylcysteine