A Six-Person CBD Fasting Comparison Was Not a Six-Person Crossover Trial
A small CBD fasting comparison did not place all six participants in matched fasted and fed syrup sessions. Only two received the same syrup in both states, limiting how cleanly the result isolates fasting from differences among people and formulations.
The overall study was larger than this comparison
Sholler and colleagues examined urinary cannabinoid profiles in 18 healthy adults after oral or vaporized CBD and a THC-containing CBD-dominant cannabis condition. The overnight-fasting experiment involved a subset of six participants receiving oral CBD syrup.
In discussing the fasting findings, the authors noted that only two of those six had also received syrup in the non-fasted state. The nominal subset size therefore should not be described as six complete within-person syrup comparisons.
The comparison had more than one limitation
Few fasting effects were observed relative to the standard low-fat breakfast condition. That null result does not establish that dietary composition never changes CBD handling: low-fat feeding and a high-fat meal are different comparisons.
The syrup also produced the lowest urinary CBD concentrations among the study’s oral formulations. Formulation and between-person variability complicated interpretation, while urine concentrations described excretion rather than directly measuring blood exposure.
What the conversion findings can support
The experiment found no apparent evidence of CBD conversion to THC under the studied conditions. The authors nevertheless described the fasting-specific evidence as inconclusive, including because of the syrup’s exposure characteristics.
The supported conclusion is narrow: this small comparison did not demonstrate the proposed effect. It cannot guarantee that every CBD product, dose or feeding condition behaves identically, and it does not turn a urine result into an assessment of functional impairment.
Related: What a within-person cannabis trial can and cannot generalize.
Research cited
Sholler DJ; Spindle TR; Cone EJ; et al.; Journal of Analytical Toxicology; 2022. Urinary Pharmacokinetic Profile of Cannabidiol (CBD), Delta-9-Tetrahydrocannabinol (THC) and Their Metabolites following Oral and Vaporized CBD and Vaporized CBD-Dominant Cannabis Administration.
