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Can You Trust the Label on Your Pot Brownie?

A new study finds that most medical marijuana products are inaccurately labeled.
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(Photo: Atomazul/Shutterstock)

(Photo: Atomazul/Shutterstock)

When Californians and Washingtonians go to medical marijuana dispensaries to buy their therapeutic pot brownies, are they getting what they're paying for? Likely not, according to a new study. After testing baked goods, drinks, candies, and other edible products from medical marijuana dispensaries in Seattle, San Francisco, and Los Angeles, a team of scientists found that most THC labels—marijuana's psychoactive chemical—are not accurate.

For those who depend on marijuana to manage symptoms such as pain or nausea, incorrect labeling can be more than frustrating; it can be harmful. If a label overstates its THC content, patients won't get the effect they need, leaving them in discomfort and pain. A label that understates its THC content, on the other hand, might give users side effects they didn't bargain for, like a stronger sense of euphoria.

The scientists—a team from Johns Hopkins University, the University of Pennsylvania, and a private lab called Werc Shop—tested 75 products, across 47 brands. They found that only 17 percent of the products accurately represented their THC content. Twenty-three percent understated their THC content, and 60 percent overstated it. Some had barely any THC at all.

Only 17 percent of the products accurately represented their THC content.

The goods also didn't contain much cannabidiol, another important therapeutic chemical found in the marijuana plant. Studies show that marijuana-based medicines work best when they have a 1:1 ratio of THC to cannabidiol, the researchers write in their paper, published yesterday in the Journal of the American Medical Association. But the products the researchers looked at had a median THC-to-cannabidiol ratio of 36:1.

What's a medical marijuana user to do? People often find it easier to get the right dose of marijuana from smoking it, but with smoking comes tar and other chemicals, similar to those in cigarettes, that irritate the lungs and could cause long-term health problems. (Regular marijuana smokers are more likely than non-smokers to report they have chronic bronchitis.) Plus, it shouldn't be up to patients to avoid what should be accurately labeled in the first place. Like any other drug or supplement, medical marijuana products should be subject to random checks for quality—and companies to penalties if they miss the mark.

Quick Studies is an award-winning series that sheds light on new research and discoveries that change the way we look at the world.