A method for amending loose smokeless tobacco with menthol for administration in clinical studies.

The results from this study suggest that a menthol spiking solution can be used to mentholate unflavored, loose ST to a target menthol content. With this method, the ST menthol content was stable for at least 24 months, and the products exposed users to menthol in a dose-dependent manner. This method yielded loose ST products with precise, stable levels of menthol to allow systematic evaluation of ST menthol content on clinical outcomes. The method may have applications for systematically evaluating changes in other tobacco product ingredients.