The health impacts of cannabis use have long been debated, but emerging research is providing clearer answers and the findings are deeply concerning.
A Risk You Can’t Ignore
People under 50 who use cannabis are more than six times more likely to have a heart attack than those who don’t. And the story doesn’t end there.
Researchers at the University of California San Francisco found that using cannabis, whether smoking or eating edibles, three or more times a week significantly affects how your blood vessels function, reducing their performance by about 50 per cent. These are the same vessels responsible for carrying oxygen and nutrients through your body. When they don’t work properly, your risk of clots, heart attacks and strokes goes way up.
It’s Not Just Smoking That’s Dangerous
What’s especially concerning is that this isn’t limited to smoking. Edibles, often thought of as the safer option, can have just as damaging an effect on your heart. That’s a major shift in what we thought we knew.
What About Cannabis and Cancer?
You’ve probably heard people say cannabis helps with cancer, but a study from the University of California San Diego tracked over 1,000 colon cancer patients and found daily cannabis users were 56 per cent more likely to die within five years of their diagnosis. Those diagnosed with cannabis addiction had an even higher risk, as they were 24 times more likely to die within that same timeframe.
The likely reason is THC, the main psychoactive compound in cannabis, which may promote inflammation and potentially help cancer cells grow. It’s a dangerous myth to believe it’s harmless or healing in these cases.
The Australian Picture
Cannabis is the most commonly used illicit drug in Australia, with over 11 per cent of Aussies reporting recent use in 2022 to 2023. That’s happening alongside another alarming reality, as cardiovascular disease remains Australia’s leading cause of death, claiming one life every 12 minutes.
When you put the two together, it’s clear that adding cannabis to the mix is a risk we can’t afford to ignore.
Bottom Line
If you’ve been thinking cannabis is a safe, natural option with no downside, the evidence says otherwise. Whether it’s your heart or your cancer outlook, the risks are real and growing.
Source:
University of California – San Francisco
Journal reference:
Mohammadi, L., et al. (2025). Association of Endothelial Dysfunction With Chronic Marijuana Smoking and THC-Edible Use. JAMA Cardiology. doi.org/10.1001/jamacardio.2025.1399.
