Defining kratom: evidence-based policy guidelines for a rapidly evolving market

The leaves of Mitragyna speciosa, commonly called kratom, have been consumed for centuries in Southeast Asia for their energizing and analgesic properties. Over the last decade kratom has gained popularity in the United States, with an estimated 10-16 million consumers, and a wide variety of products have become available in the marketplace. Along with a plethora of product formulations that contain various concentrations of kratom alkaloids, new products have emerged, labelled as "kratom", but comprised of highly concentrated synthetic alkaloids. Consumers and regulators alike struggle to differentiate the spectrum of products that range from those similar in composition to traditional kratom to those that are illegally marketed, unapproved novel drugs. With significant implications to public health policy and safety, there is a need to clearly define and differentiate kratom, kratom-derived, and synthetic products. Herein we offer guidance to support standardization of the terminology used in the manufacture and labelling of kratom and kratom-derived products in the United States. This is intended to be a reference tool for use by industry and federal, state, and other jurisdictions that oversee the kratom industry to encourage clear and consistent communication.