New Study Reveals Dangerous Health Risks Associated with Smoking Marijuana and Consuming Cannabis Gummies

Long-term cannabis use, whether through smoking or consumption of edibles such as gummies, has now been linked to a higher risk of heart disease, according to fresh research conducted by University of California, San Francisco scientists.

The study, recently published in JAMA Cardiology, found that both edible and smoked forms of marijuana negatively impact cardiovascular health by reducing blood vessel function. This reduction is a critical factor in the risk of developing serious heart conditions. The findings challenge any assumption that consuming cannabis in edible form is a safer alternative to smoking in terms of heart health.

The researchers evaluated 55 adults aged 18 to 50 who were outwardly healthy. Participants were organized into three distinct groups: regular marijuana smokers, individuals who ingested THC-infused edibles, and non-cannabis users. All cannabis-using participants reported using the substance at least three times per week for a minimum of one year. The average duration of the smoking habit was 10 years, while those consuming edibles had been doing so for about five years on average.

In September 2024, participants underwent specialized testing to assess their vascular function, specifically looking at how well their blood vessels performed and whether the endothelial cells lining these vessels showed any impairment. All regular cannabis users were found to have “decreased vascular function,” a condition that was comparable to individuals who smoke tobacco.

Notably, the blood vessel function among cannabis users was approximately half that of non-users. This degree of impairment in vascular function raises the risk of heart attacks, high blood pressure, and other potentially life-threatening cardiovascular events. Additional tests revealed that marijuana smokers also exhibited harmful changes in serum markers that impacted the cells lining both blood and lymphatic vessels—an effect that was not observed in edible users.

According to the research team, while both smoking and ingesting cannabis impaired vascular health, the mechanisms behind the impairments appeared to differ. "Chronic cannabis smoking and THC ingestion were associated with endothelial dysfunction [impaired functioning of the endothelial cells lining the inside of blood vessels] similar to that observed in tobacco smokers, although apparently occurring via distinct mechanisms," the researchers noted. They emphasized that their findings add to the growing body of evidence suggesting cannabis is not a benign substance for long-term users.

Medical professionals responded to the study by reiterating existing concerns around chronic THC exposure. One cardiologist not involved in the research stated, "We have known that the chronic use of THC-containing compounds can have negative health consequences – this study just reaffirms those prior studies." He also highlighted that the study’s small size and its reliance on Bay Area residents limited the findings’ generalizability.

Researchers acknowledged several limitations, including the variability in cannabis strains, the possibility of recall bias due to self-reported usage, and the inability to fully account for lifestyle factors such as stress, caffeine consumption, and secondhand smoke exposure. Additionally, the study measured only physiological endpoints rather than actual clinical outcomes like heart attacks, strokes, or mortality rates, which means that conclusions about long-term health impacts must be inferred rather than directly observed.

Despite these caveats, experts agree that the evidence points toward exercising caution when it comes to cannabis use, particularly for those concerned about their cardiovascular health. The study’s authors and outside clinicians alike recommend that all potential risks and benefits be carefully weighed, and that unnecessary cardiac risk should be avoided whenever possible. "If the risks outweigh the benefits, it should be avoided," one cardiologist said, underscoring the importance of informed medical decision-making.

The research was largely funded by public health and regulatory agencies, including the National Institute on Drug Abuse and several California state programs. Additional input from cannabis industry organizations may further inform the ongoing conversation about the safety profile of cannabis in all its forms as use becomes more widespread.