New Study Finds Yet Another Link Between Cannabis and Heart Disease

The debate about the safety of cannabis rages on, with more studies indicating that the herb may not be completely harmless. One particular study published as a preproof in JACC: Advances suggests a link between cannabis use and cardiovascular disease (CVD) events in adults under 50. While you might be skeptical about this claim, the data are quite compelling.

Key Findings of the Study

The 2025 study, led by doctors Ibrahim Kamel, Benjamin Horn, and other medical practitioners, compared data from over 4.6 million adults under the age of 50. About 2% of these adults used cannabis, and the study discovered that compared to the non-cannabis users, these individuals had:

• 6x higher risk of heart attack (Average risk [AR], 0.558% vs 0.09%)
• 4x higher risk of ischemic stroke (AR, 0.405% vs 0.094%)
• 3x higher risk of major adverse cardiovascular events (AR, 1.187% vs 0.366%) 
• 2x higher risk of heart failure (AR, 0.861% vs 0.424%)
• 50% higher risk of dying from a cardiovascular or non-cardiovascular issue (AR, 1.262% vs 0.841%)

These shocking numbers suggest an association between cannabis use and an increased risk of cardiovascular events and mortality.  According to Kamel, “The striking thing is that we found that there were risks in every single cardiovascular endpoint that we looked at: myocardial infarction (MI), heart failure, all-cause mortality. Everything had a risk, with the highest [being for] MI.”

Because of his findings, Kamel strongly recommends that doctors screen younger patients with cardiovascular concerns for cannabis use. Doing so could help rule out cannabis for patients with preexisting CVD, at high risk of CVD or CV events, or identify it as a possible cause of a patient’s heart problems.

Two Sides to Cannabis’s Effects on Cardiovascular Health

Cannabis’ effect on heart health has never been a one-sided story. You have Kamel’s research and other studies, such as a 2022 Stanford Medicine report, that show smoking cannabis may increase the risk of experiencing heart issues, including a premature heart attack.

According to Kamel and his colleagues, cannabis negative effects on the heart likely stem from cannabinoids disrupting regular heart rhythm, causing arrhythmias. They also pointed out that cannabis use may trigger a surge in pro-inflammatory cytokines that damage blood vessels and prevent them from relaxing. Both can contribute to the reduced function of the heart’s small blood vessels.

Let’s not forget earlier studies like the Role of Cannabis in Cardiovascular Disorders and the Impact of Marijuana on the Cardiovascular System, which state that heavy cannabis use may cause:

• Blood pressure spikes
• Irregular heart rhythms and ventricular tachycardia
• Ischemic stroke
• Heart muscle disorders
• Blood artery inflammation

All of which may result in severe cardiac events.

Then you have the flip side of the research coin, which suggests other cannabinoids like CBD might help alleviate heart issues. Take, for example, the 2017 study of cannabidiol (CBD), which indicates that the cannabis compound could reduce blood pressure and arrhythmias in response to stress with a single dose. Test subjects in the study took 600 mg of CBD and experienced reduced resting systolic blood pressure and decreased stroke volume after cold stress.

Another study shows that CBD may help protect the heart in test animals by reducing irregular heartbeats and the size of heart damage if taken before a heart attack. Interestingly, these effects were stronger with higher doses. There’s also a 2015 lab study that revealed CBD’s potential for relaxing blood vessels and improving blood flow by working with CB1 receptors and TRP channels.

Lastly, a 2019 preclinical investigation suggests that CBD is a vasodilator that expands blood vessels, reducing vascular resistance and improving blood flow. This effect may help the heart pump more efficiently to minimize high blood pressure, arrhythmia, and other cardiovascular disorders. However, clinical support for the role of CBD in CVD is just starting out.

The conflicting outcomes of these studies show that cannabis effect on the heart is complex and requires more research. Kamel even pointed out that while his study team screened out cigarette smokers, “Users of cannabis may also use cocaine and other substances that were not accounted for in the analysis.” Cannabis smoking also wasn’t assessed, and these other substances may also have played a role in why Kamel’s participants experienced cardiovascular issues.

Should You Just Avoid Cannabis?

You should always talk to your doctor before taking or stopping cannabis, as your situation and CV risk may vary. But you don’t necessarily have to quit cannabis altogether if it’s improving your quality of life. After all, you aren’t going to toss your smartphone because you heard it might be emitting cancer-causing radio waves. So, if cannabis helps relieve your stress, anxiety, pain, and other issues, quitting it may not be your best option. Instead, you should look into using cannabis in a way that’s less likely to hurt you, or other non-THC cannabinoids.

For instance, smoking and vaping cannabis deliver therapeutic effects faster than other consumption methods. However, inhaling anything but fresh air into your lungs can cause respiratory problems. Fortunately, you may reduce the likelihood of such health troubles by ingesting instead of smoking cannabis. You can also try cannabis tinctures or even suppositories.

Furthermore, high-THC cannabis may be more likely to cause heart issues. One study of the Cardiovascular Effects of Marijuana showed that high THC doses can raise blood pressure and heart rate in the short term, while lowering these in the long term. However, repeated or prolonged cardiovascular strain from acute cannabis use may increase the risk of experiencing heart attacks, strokes, and other complications.  

A notable caveat to this study is that participants weren’t specifically asked about cannabis smoking. They just mention general cannabis use, which confounds these results. That’s because any kind of smoking can be harmful, decrease oxygen levels, increase carbon monoxide, provoke anginal symptoms, disrupt endothelial vasculature, clot blood, and generate other risky particles in the process that may contribute to CVD and related events.

Read: New Discovery: This Supplement Could Help Mitigate Cannabis Negative Impacts on the Heart

How Can You Use Cannabis with Fewer Health Risks?

Since cannabis affects everyone differently, it helps to consult your doctor before trying it. Your doctor may advise against it if you have a family history of heart disease, take certain medications, or have a condition that increases CV risk (e.g., diabetes, high blood pressure) or something else that interacts poorly with cannabis.

Even if your doctor gives the all-clear, you never know, so minimize health risks with these cannabis safety tips:

• Choose Low-THC or Hemp Products: If using cannabis recreationally, you don’t need over 90% THC to have a good time. Products with less than 10-20% THC are typically enough to cause euphoric effects and may be less likely to endanger your heart or mental health. You should also consider hemp products like CBD or CBG oils for even less THC (<0.3%) and non-impairing daytime use to truly minimize these risks.
• Eat More Soy: Genistein, a molecule found in soybeans and fava beans, is shown to lessen cannabis impact on the heart. Incorporate more tofu, soy milk, soy sauce, and other soy and fava bean products into your diet to protect your heart while using cannabis.
• Smoke and Vape Less: You can get your desired cannabis effects from edibles, tinctures, and other concentrates that won’t endanger your cardiovascular or respiratory health.
• Start Low, Go Slow: Taking too much cannabis can cause undesired effects, such as paranoia, anxiety, and palpitations, none of which are good for your heart. Avoid overdosing by starting with a small dose, especially if you’re new to cannabis.
• Stay Hydrated and Eat Well: Proper nutrition and hydration support cardiovascular health and may help minimize blood pressure fluctuations from cannabis use.
• Pay Attention: If you feel discomfort, dizziness, or chest pain after using cannabis, seek medical attention.