What peer‑reviewed clinical trials exist testing CBD (cannabidiol) for glycemic control or insulin sensitivity?
Executive summary
The peer‑reviewed clinical trial landscape testing cannabidiol (CBD) specifically for glycemic control or insulin sensitivity is very small and inconclusive: the principal randomized, double‑blind, placebo‑controlled pilot trial (Jadoon et al.) found few clinically meaningful improvements versus placebo, with CBD altering some adipokines and gut hormones only versus baseline but not versus placebo [1] [2]. Other human reports cited in reviews and advocacy outlets describe small sublingual CBD/THC studies that reported glycemic improvements, but these are limited, heterogeneous, and not sufficient to change clinical practice [3] [4].
1. The main peer‑reviewed randomized trial and what it actually showed
The landmark peer‑reviewed clinical trial in diabetes care randomized 62 people with non‑insulin‑treated type 2 diabetes to CBD 100 mg twice daily, THCV 5 mg twice daily, two CBD/THCV combinations, or placebo for 13 weeks in a double‑blind, placebo‑controlled design and is the primary direct clinical evidence testing CBD in this population [1]. That study reported that CBD produced statistically significant changes in two biomarkers — a decrease in resistin and an increase in glucose‑dependent insulinotropic peptide (GIP) — when compared with baseline, but those changes did not reach significance against placebo and CBD failed to produce detectable improvements in standard metabolic end points such as fasting glucose, HbA1c, or insulin sensitivity measures in the controlled analysis [2] [1].
2. Other clinical reports and combination studies: noisy signals, limited reproducibility
Beyond the Diabetes Care pilot, the literature cited in reviews refers to a Phase I sublingual CBD/THC regimen and small cannabinoid combination trials that reported improvements in fasting glucose, HbA1c, OGTT results and reductions in insulin secretion, but these are described in secondary sources and advocacy summaries and are heterogeneous in design, dosing, and endpoints — meaning they cannot be treated as definitive, standalone evidence for CBD monotherapy in glycemic control [3] [4]. Advocacy and health‑information sites reiterate these mixed signals while appropriately noting the small scale and limitations of the trials [5] [6].
3. Preclinical promise vs clinical reality
Animal and mechanistic studies have repeatedly suggested that CBD can influence insulin sensitivity, inflammation, and metabolic pathways at various doses, and review articles synthesize these signals as biologically plausible reasons to test CBD in humans [3]. Nevertheless, translation from animal models to patient‑relevant outcomes has not occurred convincingly: the only large randomized human pilot failed to demonstrate clinically meaningful glycemic benefit of CBD versus placebo, even if some surrogate biomarkers shifted [1] [2].
4. The role of THCV and combination therapies — an important caveat
The Diabetes Care trial flagged THCV, a different cannabinoid tested at low doses, as showing more promising glycemic effects than CBD and therefore as a candidate for further study, underscoring that not all cannabinoids behave the same and that positive reports from mixed CBD/THC regimens do not prove CBD’s efficacy alone [1]. Some positive human reports concern combination sprays or formulations that include THC or other cannabinoids, complicating attribution of any metabolic effects to CBD specifically [4] [3].
5. Bottom line, clinical guidance, and research gaps
Peer‑reviewed clinical evidence testing CBD alone for glycemic control or insulin sensitivity is essentially limited to one rigorously conducted pilot randomized trial that found biomarker changes versus baseline but no clear benefit versus placebo, and to a handful of small, heterogeneous combination trials reported in secondary sources [1] [2] [3]. Major diabetes guidance and reviews still do not endorse CBD for glucose lowering, and reviews explicitly call for larger, well‑controlled human trials measuring robust endpoints (HbA1c, insulin sensitivity indices, CGM metrics) before any clinical recommendation can be made [7] [3]. Some stakeholders — industry, advocacy groups, and media outlets — emphasize promising signals to support commercialization, which creates an implicit agenda to oversell preliminary findings; rigorous peer‑reviewed replication is the current missing piece [4] [8].