A new study from British American Tobacco scientists answers that fascinating question, providing valuable information for consumers and regulators.
Snus contains nicotine and other constituents that make tobacco satisfying, but it also contains contaminants, albeit in vanishingly small amounts. It is useful to know how much of these constituents users extract and consume during typical use.
Dr. Helena Digard and colleagues published their research in Chemistry Central Journal (abstract here). They recruited 21 male snus users in Sweden to use four 1-gram pouched snus products for one hour. They then compared constituent levels in the used pouches with levels in unused pouches from the same package.
The researchers found that the percentage extraction of constituents from snus was fairly consistent, even though they were present in concentrations that differed by almost a million-fold. For example, users extracted about one-quarter of the available salt (sodium and chloride), which was present in milligram quantities in the snus pouches. Also present in milligram quantities was propylene glycol, the solvent used in many e-cigarettes, of which about 30% was extracted; a third of the available nicotine was consumed.
Several constituents, including ammonium (28% extracted), nitrate (27%), and flavorings (19-30%), were present in microgram quantities (one thousand times smaller than milligrams). Tobacco-specific nitrosamines were present in nanogram quantities (one millionth of a milligram); about 36% were extracted.
This study’s results were reasonably consistent with those from research published in 2012 by John Caraway and P.X. Chen of Reynolds American (abstract here), although the latter work showed somewhat lower extraction of TSNAs and slightly higher extraction of nicotine. As Nigard et al. acknowledged, there is wide variation in the percentage of extraction among different snus users and even by a single user on different occasions.