The study, led by Leila Mohammadi at the University of California, San Francisco (UCSF) and published in the peer-reviewed medical journal JAMA, examined the potential connection between THC smoking and ingestion, and endothelial dysfunction—where the inner lining of blood vessels, the endothelium, is unable to function properly and could lead to an array of cardiovascular problems, per The Cleveland Clinic. This cross-sectional study of 55 participants discovered that vascular endothelial function was impaired in both chronic marijuana smokers and tetrahydrocannabinol (THC) edible users, whereas serum from marijuana smokers but not THC-edible users blunted nitric oxide production in cultured endothelial cells. These studies highlighted impaired blood vessel function and a higher likelihood of heart attacks among marijuana users, echoing risks previously associated with tobacco smoking but “via different mechanisms.” Such findings could challenge previous assumptions that marijuana is a benign alternative to tobacco.