Daily cannabidiol and L-theanine beverage consumption does not alter anxiety, fatigue, cognitive function, or natural killer cell function: A randomized, controlled trial in healthy, young adults

Cannabidiol (CBD), a non-psychotropic Cannabis sativa derivative, and L-theanine, a green tea derivative, are gaining attention as potential promotors of psychological and cognitive health. The purpose of this double-blind, randomized, placebo-controlled study was to determine whether eight-week, daily consumption of beverages containing CBD, along with L-theanine, would improve psychological health, cognitive function, serum brain-derived neurotrophic factor (BDNF) as well as innate immune cell quantity and function in young, healthy adults. A total of 102 healthy participants were randomly assigned to, and successfully completed, 8 weeks of one of four treatment arms: 1) 60 mg CBD plus L-theanine (CB60; n = 25); 2) 30 mg CBD plus L-theanine (CB30; n = 28); 3) vehicle containing only L-theanine (LTV; n = 24); and 4) a calorie-matched placebo (PLAC; n = 25). After 8 weeks, plasma cannabinoid metabolite concentrations were significantly increased (p < 0.001) in CB60 and CB30 groups. There were no significant changes in anxiety, fatigue, and cognition, or serum BDNF concentrations as a result of the intervention and no treatment-related changes in natural killer (NK) and NKT cell populations or function. ClinicalTrials.gov (NCT05189275).