Harvard study confirms what Michigan stoners already know about using weed

New research from Harvard Medical School shows that cannabis users aren’t at greater risk of emphysema or lung damage. Tobacco users, though? Not so lucky.  

MICHIGAN—If you’ve ever lit up and worried about what it’s doing to your lungs, you’re not alone. But according to new research published in the journal Current Problems in Diagnostic Radiology, that fear might be misplaced—at least when it comes to cannabis.

Researchers at Harvard Medical School analyzed chest scans from nearly 300 people and found a clear pattern: Tobacco smokers showed major lung damage. Cannabis users did not.

In fact, just 4% of marijuana-only users showed signs of emphysema, compared to 62% of cigarette smokers. The study also found far less airway inflammation in weed-only smokers. 

But here’s the thing: The study didn’t focus specifically on cannabis smokers. It looked at cannabis users—a group that may have included people who vape, eat edibles, use tinctures, or otherwise consume in non-combustive ways. So, while the results present some good news for cannabis consumers, it’s hard to say exactly how much combustion played a role.

What the study does suggest is that cannabis, as a substance, doesn’t appear to produce the same kind of long-term lung damage that tobacco does—especially when consumed through less harmful delivery methods.

And it’s not a fluke. This study adds to a growing body of research showing that cannabis and tobacco do not carry the same risks—and don’t affect your lungs the same way.

A 2018 study in Chest found no link between long-term cannabis use and lung cancer. Multiple studies—including one from the National Academy of Sciences—have also found no significant connection between marijuana use and COPD, emphysema, or upper respiratory cancers. 

NORML’s deputy director, Paul Armentano, put it bluntly:

“It makes no sense from either a public health standpoint or from a political standpoint to continue to treat marijuana as if it is more dangerous, or even equally as dangerous, as tobacco,” Armentano said in a statement. “The science is clear and consistent; it is not.”

What Michigan Smokers Should Know

Weed has been legal in Michigan for several years, but that doesn’t mean the stigma is gone. Plenty of cannabis consumers still worry that lighting up might be wrecking their lungs.

This study should offer some real peace of mind. It backs up what a lot of Michiganders have already seen firsthand: Cannabis isn’t causing the same long-term damage that tobacco does.

Whether you’re a medical user managing chronic pain or just a recreational smoker unwinding after work, you can feel better knowing the science is catching up to your lived experience.

It also adds weight to the growing push for smarter policy. Michigan has a well-regulated market, but cannabis is still stuck in federal legal limbo. Studies like this give advocates and lawmakers more firepower to demand more changes—like expanding access to medical research. Because at this point, pretending weed is as dangerous as cigarettes isn’t just wrong—it’s holding us back.

READ MORE: 7 quick hits of cannabis news from across Michigan

Want more cannabis news delivered right to your inbox? Click here to sign up for The MichiGanja Report—our free weekly newsletter about all things marijuana.