Evaluation of the mitragynine content, levels of toxic metals and the presence of microbes in kratom samples purchased in the Western Suburbs of Chicago

Abstract

Kratom (Mitragyna speciosa) is an herbal product, indigenous to Southeast Asia, that has both stimulant and opioid‐like effects. Kratom leaf products are being increasingly used in the West for their reputed benefits in the treatment of pain and opioid use disorder. Recently, the US FDA and CDC have raised concerns regarding the contamination of some kratom products with toxic metals (Pb and Ni) and microbes such as Salmonella. To further explore this issue, 8 different kratom products were legally purchased from various “head”/”smoke” shops in the Western Suburbs of Chicago and then tested for microbial burden, a panel of metals (Ni, Pb, Cr, As, Hg, Cd), and levels of the main psychoactive alkaloid mitragynine. All of the samples contained significant, but variable, levels of mitragynine (3.9–62.1 mg/g) indicating that the products were, in fact, kratom. All but 2 of the samples tested positive for the presence of various microbes including bacteria and fungi. However, none of the samples tested positive for Salmonella. The same 6 samples that contained microbes also showed significant levels of Ni (1.7–7.9 μg/g), Pb (0.32–1.7 μg/g) and Cr (0.23–4.1 μg/g) while the other 2 samples were negative for metals. These data indicate that many kratom products contain variable levels of mitragynine, and can contain significant levels of toxic metals and microbes. These findings highlight the need for more stringent standards for the production and sale of kratom products.Support or Funding InformationThis work was supported by personal funds from Dr. Walter Prozialeck and by restricted funds from Midwestern University.