Chronic Cannabis Use Linked to Increased Cardiovascular Risk

Cannabis use is soaring across the United States, but a new study from the University of California, San Francisco (UCSF) challenges the widespread belief that marijuana is a harmless substance—especially when consumed as edibles. Published in JAMA Cardiology on May 28, 2025, the research reveals a surprising and concerning link between chronic cannabis use and impaired cardiovascular health.

Researchers studied 55 healthy adults aged 18 to 50 who did not use nicotine or face secondhand smoke exposure. Participants were divided into three groups: marijuana smokers, edible users, and non-users. Those in the cannabis groups used THC at least three times weekly. The team measured vascular function by assessing how well the brachial artery in the arm dilated in response to increased blood flow—a key indicator of cardiovascular health.

The results were striking: non-users showed an average artery dilation of 10.4%, while smokers and edible users exhibited significantly reduced dilation of 6.0% and 4.6%, respectively. For context, healthy individuals typically range from 8.0% to 15%. This means cannabis use—regardless of intake method—can reduce vascular function by nearly half, increasing risks of heart attacks and strokes.

Digging deeper, the UCSF team explored how THC affects endothelial cells lining blood vessels. They discovered that blood from chronic cannabis smokers inhibited nitric oxide production—a molecule essential for vessel dilation. Interestingly, this effect was absent in edible users, suggesting different mechanisms of vascular impairment depending on consumption method, which warrants further investigation.

These findings add to a growing body of evidence linking chronic cannabis use with cardiovascular damage. A 2024 study in the Journal of the American Heart Association reported a 25% higher risk of heart attack and a 42% higher risk of stroke among daily cannabis users. As legalization expands and usage rises, understanding these risks becomes critical for public health messaging and clinical guidelines.

Why does this matter? Because many people assume edibles are a safer alternative to smoking, but this study shows that both forms can impair artery function significantly. It’s a wake-up call for consumers, healthcare providers, and policymakers alike to reconsider cannabis safety and invest in further research to unravel the complex cardiovascular effects of THC.

In a landscape where cannabis is increasingly normalized, this study serves as a crucial reminder: not all that is natural is risk-free. The vascular impairments linked to THC use could translate into serious health consequences over time. As the scientific community races to understand these effects, users should approach cannabis with informed caution.

Future research will need to confirm these findings in larger populations and explore the distinct biological pathways through which smoked and edible cannabis affect cardiovascular health. Meanwhile, public health messaging must evolve to reflect these emerging risks and guide safer consumption practices.