Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco
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Menthol has long been an important flavorant in tobacco products, and both its historical and present uses are topics of increasing debate. Menthol can exist in eight different stereoisomeric forms (as four enantiomeric pairs) that possess different sensory properties. As regards use in tobacco products, the open scientific literature and available industry documents focus on the D-menthol and l-menthol enantiomeric pair, and in particular on l-menthol, but are ambiguous about the actual importance of D-menthol in tobacco products. This study provides the first openly available measurements regarding the stereoisomeric forms of menthol as found in selected United States sub-brands of smokeless tobacco (SLT), cigarettes, and cigarette smoke. ⋯ For the selected cigarettes and SLT products tested from the U.S. market, the only form of menthol found was l-menthol. Other forms may be present in products that were not tested. No evidence was found of thermal racemization upon smoking of l-menthol to a d+l mixture.