Abstract
INTRODUCTION: In addition to imparting flavor, menthol in menthol-flavored cigarettes enhances nicotine addiction and increases experimentation, initiation, and progression to regular smoking. Menthol can be added to cigarettes at perceptible levels (so-called flavored cigarettes or characterized flavored cigarettes) or non-perceptible levels (subliminal). Our objective was to understand the reasons that tobacco companies use subliminal menthol. METHODS: We identified previously secret internal tobacco company documents dated 1955-2012 in the Truth Tobacco Industry Documents archive on menthol at subliminal levels. RESULTS: Beginning in at least the 1950s, tobacco companies used subliminal menthol to compensate the flavor loss caused by filters, reduce smoke harshness, reduce dryness, and increase smoke coolness. Varying menthol concentrations were considered to help convert people who smoke non-menthol to menthol brands, possibly because people who use menthol cigarettes have more harship quitting than people who use non-menthol cigarettes. CONCLUSIONS: Menthol is an important additive beyond its function as a "characterizing flavor." Tobacco companies use menthol in "non-menthol" cigarettes at subliminal (non-perceptible by the people who smoke cigarettes) levels to improve taste, make them easier to smoke and facilitate initiation, and possibly convert people who smoke non-menthol cigarettes to menthol cigarettes.