Cannabis Use Is Linked to Lower Odds of Type 2 Diabetes, but Causation Remains Unclear
A 2023 systematic review and meta-analysis found that cannabis exposure was associated with lower odds of type 2 diabetes—but the evidence does not show that cannabis prevents the disease or should be used as a treatment.
Published in Phytotherapy Research, the analysis by researchers at Tabriz University of Medical Sciences examined seven studies comprising 11 surveys and four cohort analyses. Across the pooled data, people who reported cannabis exposure had 0.48 times the odds of type 2 diabetes compared with those who reported no exposure, with a 95% confidence interval of 0.39 to 0.59.
Because most of the underlying evidence was observational, the finding indicates an association rather than a cause-and-effect relationship. Cannabis users may differ from nonusers in ways that are difficult to measure fully, including diet, physical activity, tobacco use, access to health care, other substance use, and socioeconomic factors. The researchers also noted substantial variation among the studies and called for better-quality research, including prospective studies and clinical trials.
Type 2 diabetes develops when the body does not use insulin effectively and, over time, cannot produce enough insulin to keep blood glucose within a healthy range. This process—often involving insulin resistance—can contribute to cardiovascular disease, kidney disease, nerve damage, and vision problems. The National Institute of Diabetes and Digestive and Kidney Diseases identifies maintaining a healthy weight and being physically active as important ways to help prevent or manage insulin resistance and prediabetes.
Some of the studies included in the broader evidence base point in a similar direction, but they have important limitations. For example, a 2020 analysis of 10,445 people with chronic hepatitis C in the French ANRS CO22 Hepather cohort found that current and former cannabis use were associated with lower odds of diabetes after statistical adjustment. However, that study used cross-sectional data, so it could not establish whether cannabis use influenced diabetes risk.
Separate research has examined specific cannabinoids rather than cannabis use itself. In a small randomized pilot trial involving 62 people with non-insulin-treated type 2 diabetes, tetrahydrocannabivarin, or THCV, was associated with lower fasting glucose and changes in measures of pancreatic beta-cell function over 13 weeks. The trial tested purified cannabinoid preparations, not cannabis consumption, and was not designed to determine whether cannabis prevents type 2 diabetes.
The meta-analysis therefore provides a reason for further investigation, not a medical recommendation. Until larger and more rigorous studies clarify the relationship, cannabis should not be considered a proven strategy for preventing or treating type 2 diabetes. People with diabetes or prediabetes should discuss cannabis use and any proposed cannabinoid products with a qualified health professional, particularly because product potency, formulations, and potential side effects vary widely.
