Chemical Analysis and Alkaloid Intake for Kratom Products Available in the United States.

Previously, we used ecological momentary assessment (EMA) to evaluate motivations and temporal patterns of kratom use for 15 days among US adult kratom consumers (N = 357). Here we present the content analyses of the products used during that nationwide study, with quantification of 10 kratom alkaloids. The samples (N = 341) were primarily whole-leaf products, not extracts, and were similar to each other in their alkaloid composition, closely matching the chromatographic-mass spectrometry fingerprint expected for Mitragyna speciosa leaf material. We found no evidence of adulteration with illicit or prescription drugs. With participants' self-reported data on kratom amount per use, we calculated mitragynine intake per use: mean 31.3 mg and median 25.4 mg (range 2.0-205.9 mg). With self-reported data on frequency, we calculated mitragynine intake per day, it ranged from 78.3 to 134.6 mg (mean) or 50.8 to 101.6 mg (median). This is the most comprehensive analysis of US whole-leaf kratom products to date. The coupling of self-report and product sample-analysis data to quantify daily alkaloid intake is foundational for designing controlled clinical trials of kratom in healthy volunteers. These findings on kratom products' chemical composition and daily kratom alkaloid consumption can also inform clinicians, policymakers, and consumers, particularly for whole-leaf material.