A newly released study by University of California San Francisco has uncovered compelling evidence that regular cannabis use, whether smoked or eaten as edibles, poses significant risks to cardiovascular health—on par with those seen in tobacco smokers. The findings, published in JAMA Cardiology on May 28, hold broad implications for communities worldwide, including Thailand, where cannabis reform remains a subject of careful debate and rapid market growth.
The research is particularly significant given that Thailand became the first Asian nation to decriminalise cannabis in 2022, sparking a “green rush” of dispensaries, edible products, and wellness treatments across the country. However, as debates over the benefits and drawbacks of cannabis legalization intensify, the new UCSF data brings overdue scientific scrutiny to the long-term health implications for the Thai public.
The UCSF study recruited 55 otherwise healthy adults between 2021 and 2024, each of whom reported regular cannabis use—specifically, consuming marijuana by smoking or by edible means at least three times per week for more than one year. Importantly, all participants refrained from nicotine use, allowing the team to isolate the effects of cannabis itself. Marihuana smokers averaged a decade of steady use; edible users, five years.
What researchers found is troubling: Both groups, whether they smoked marijuana or used edibles containing THC (the psychoactive compound in cannabis), experienced reduced vascular function. The drop in blood vessel flexibility and responsiveness was “roughly by half” compared to participants who did not use cannabis, a deficit closely linked in medical literature to higher risk of heart attack, hypertension, and related cardiovascular events (UCSF News).
Delving deeper, scientists observed that those who smoked cannabis showed alterations in their blood serum that were especially damaging to endothelial cells—the delicate lining that maintains healthy arteries and veins. Curiously, this particular harmful blood serum profile was absent in those who consumed only edibles, indicating that the mechanics of cardiovascular harm differ depending on the route of THC consumption. Nonetheless, both groups suffered comparable loss of vascular function, leaving researchers to conclude that cannabis harms the cardiovascular system by more than one mechanism.
Dr. Leila Mohammadi, one of the lead authors, said in official statements that the findings “suggest smoking marijuana negatively affects vascular function for different reasons than ingesting THC does.” Senior author Dr. Matthew L. Springer agreed, noting that “whatever the mechanism, the net effect is that all chronic users must be considered at elevated risk for cardiovascular disease until future research can clarify safe thresholds—if any exist” (UCSF News).
Medical experts worldwide have responded to the data with concern, particularly as many national policies began shifting toward looser cannabis regulations in the last decade. A cardiovascular researcher at the American Heart Association, unconnected to the UCSF project, said that “these results reinforce our longstanding warnings that cannabis is far from harmless, especially for those with pre-existing high blood pressure or a family history of heart disease” (ScienceDaily summary). Another expert opined: “It’s crucial for public health campaigns to bring nuance—cannabis may help with certain medical conditions but it can still harm the heart, especially if chronically consumed.”
For the Thai public, these revelations should not be understated. Thailand’s rapid embrace of commercial cannabis—including smoking lounges, THC-infused beverages, and a thriving edible market—has outpaced careful regulation and consumer education. Industry data tracked by government agencies suggest there are now over 6,000 registered cannabis businesses nationwide, particularly concentrated in tourist hubs like Bangkok, Chiang Mai, and Pattaya (Bangkok Post). Meanwhile, public messaging has largely emphasized economic opportunity and “wellness” rather than potential cardiovascular risks.
In practice, this could translate into thousands of Thais—especially youths and working-age adults—unknowingly exposing themselves to chronic vascular injury now documented in scientific literature. The cultural context is also crucial: while traditional Thai medicine often incorporates herbal remedies, and the recent policy shift was partly justified by “traditional use,” smoking or eating highly concentrated THC products bears little resemblance to age-old preparations.
Historically, Thailand’s health policy community has weathered similar debates. For decades, anti-smoking campaigns have sought to highlight the catastrophic toll of tobacco on public health, especially regarding heart disease and stroke. With the new UCSF findings, medical and regulatory authorities are being pressed to clarify cannabis messaging to reflect the actual risks: regular marijuana use poses a threat to cardiovascular health that equals, and in some ways mirrors, tobacco consumption.
Moving forward, experts urge the Thai public to “exercise the utmost caution” with cannabis use, particularly for those with histories of hypertension, heart arrhythmia, diabetes, or obesity—all of which increase one’s baseline vulnerability to heart disease. Physicians at Thailand’s leading public hospitals recommend routine screening for blood pressure, cholesterol, and vascular function among adults who report regular cannabis use, echoing the preventive standards already in place for tobacco.
Looking to the future, the UCSF team emphasizes that further research is vital—not only on dose-response and frequency relationships but also on whether risks dissipate after cessation or if certain vulnerable populations (like the elderly or those with underlying disease) face even greater danger. Policymakers, including those at Thailand’s health ministry and regulatory agencies, may need to consider these findings as they refine rules on sales, marketing, and public awareness.
For individual Thai readers, the actionable message is clear: just because cannabis is now legal does not mean it is harmless. Anyone considering regular cannabis use—whether for recreation, wellness, or medical reasons—should weigh these new cardiovascular findings and consult a healthcare professional, particularly if they possess risk factors for heart disease. As scientific understanding deepens, making informed decisions and maintaining regular health screening are the best protections amid evolving cannabis norms.
Sources for this story include the official UCSF summary, ScienceDaily overview, and recent reporting by Bangkok Post.