A new study published May 28 in JAMA Cardiology suggests that regular cannabis use—whether smoked or consumed via edibles—may significantly impair blood vessel function, posing potential cardiovascular risks similar to those seen in tobacco smokers.
The federally funded research analyzed 55 healthy adults aged 18 to 50 who reported using cannabis at least three times a week for over a year. The study found that cannabis users had vascular function reduced by roughly 50% compared to non-users, a degree of dysfunction comparable to that found in cigarette smokers.
Smokers in the study averaged 10 years of cannabis use, while those who consumed edibles averaged five. While both groups showed reduced blood vessel function, cannabis smokers had additional harmful blood serum changes that appeared to damage endothelial cells—the inner lining of blood and lymphatic vessels.
The mechanism by which THC, the psychoactive compound in cannabis, affects vascular health remains unclear. However, decreased blood vessel function is associated with higher risks for heart attack, hypertension, and other cardiovascular conditions.
“There is a popular belief that marijuana smoke is harmless,” the researchers noted. “However, marijuana smoke contains many of the same harmful chemicals and fine particles found in tobacco smoke.”
The findings come as marijuana use continues to rise nationwide. Cannabis is now the most commonly used illicit drug in the U.S., with about 52.5 million users in 2021, according to the CDC. Use among older adults is also climbing, with past-30-day use increasing from 4.8% in 2021 to 7% in 2023 for those over 65—a population potentially more vulnerable to adverse effects.
Despite increasing legalization for medical and recreational use across 39 states and D.C., experts are urging caution. “Our brains are more sensitive to psychoactive substances as we age,” said Dr. Benjamin Han, a geriatrician at UC San Diego.
While cannabis can offer benefits—like pain relief, seizure control, and nausea reduction—experts emphasize the need for more research into its long-term health impacts. As legalization spreads, the authors stress, understanding cannabis’s full effects on cardiovascular health is essential.
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