Objectives: We measure for the first time how commercially available Cannabis flower products affect feelings of fatigue. Methods: A total of 1,224 people recorded 3,922 Cannabis flower self-administration sessions between June 6, 2016, and August 7, 2019, using the Releaf App. Usage sessions included real-time subjective changes in fatigue intensity levels prior to and following Cannabis consumption, Cannabis flower characteristics (labeled phenotype, cannabinoid potency levels), combustion method, and any potential experienced side effects. Results: On average, 91.94% of people experienced decreased fatigue following consumption with an average symptom intensity reduction of 3.48 points on a 0–10 visual analog scale (SD = 2.70, d = 1.60, p < 0.001). While labeled plant phenotypes (“C. indica,” “C. sativa,” or “hybrid”) did not differ in symptom relief, people that used joints to combust the flower reported greater symptom relief than pipe or vaporizer users. Across cannabinoid levels, tetrahydrocannabinol, and cannabidiol levels were generally not associated with changes in symptom intensity levels. Cannabis use was associated with several negative side effects that correspond to increased feelings of fatigue (e.g., feeling unmotivated, couch-locked) among a minority of users (<24% of users), with slightly more users (up to 37%) experiencing a positive side effect that corresponds to increased energy (e.g., feeling active, energetic, frisky, or productive). Conclusions: The findings suggest that the majority of patients experience decreased fatigue from consumption of Cannabis flower consumed in vivo, although the magnitude of the effect and extent of side effects experienced likely vary with individuals’ metabolic states and the synergistic chemotypic properties of the plant.
