Sex-specific association between low oral doses of cannabidiol (CBD) and plasma concentration of anandamide (AEA), N-palmitoylethanolamine (PEA) and N-oleoylethanolamine (OEA) in healthy occasional cannabis users

BACKGROUND: Cannabidiol (CBD), a phytocannabinoid produced by Cannabis sativa, is widely consumed and interacts with components of the endocannabinoid system, including enzymes and receptors, through indirect and complex mechanisms. However, how CBD influences endogenous cannabinoids such as anandamide (AEA), and related N-acylethanolamines like N-palmitoylethanolamine (PEA) and N-oleoylethanolamine (OEA), remains poorly understood. This study investigates the acute impact of marketed CBD doses on the plasmatic levels of these signaling lipids in occasional cannabis users, addressing a critical gap in understanding the biological effects of low-dose CBD in non-therapeutic contexts. METHODS: In a triple-blind, placebo-controlled, randomized crossover trial, 70 healthy volunteers received ten sequences of four oral CBD doses (20, 50, 100, 200 mg) and placebo. Blood was sampled at baseline and five timepoints post-dose. Plasma AEA, PEA, and OEA were quantified by LC–MS, and dose–response assessed with linear mixed-effects models on plasma concentrations (model 1) and Area Under the Curve to increase (AUCi, model 2), including participant ID (nested in sequence) as random effect, and visit, sequence, sex, and baseline levels as fixed effects. RESULTS: Model 2 revealed a significant effect of CBD dose on AUCi of PEA and OEA, but not AEA. Pairwise comparisons showed that placebo was associated with significantly higher AUCi values than the 50 mg dose (p < 0.05; moderate effect sizes), and trended higher than the 200 mg dose (p < 0.10; small-to-moderate effect sizes). No differences were observed for other dose contrasts. Importantly, sex emerged as a significant factor: sub-group analyses indicated that these reductions in AUCi were driven by female participants, with lower PEA and OEA exposure confirmed at both 50 mg and 200 mg (only PEA) compared to placebo. No corresponding effects were observed in males. All plasma levels decreased overall throughout each visit, at every dose of CBD and placebo. CONCLUSIONS: This study revealed that among healthy adults who consume cannabis occasionally, low-dose oral CBD formulations were able to significantly decrease the cumulative plasma levels of PEA and OEA in a female-specific fashion, confirming the importance of sex-differences in cannabinoid response, and emphasizing the relevance of a personalized approach to cannabis consumption and its effects, as well as public health messaging. TRIAL REGISTRATION: (ClinicalTrials.gov, registration: NCT05407285, Registration date: 2022–06-02).