CBD products often have more THC than claimed, research suggests. For example, a 2017 study in JAMA found that 18 of 84 CBD products, all purchased online, had THC levels possibly high enough to cause intoxication or impairment.
And those elevated levels might also be high enough to cause you not to pass a drug test.
That’s what Horn, the truck driver from New York, alleges happened to him after taking a product advertised to contain “zero THC.”
After losing his job because of the failed drug test, the lawsuit says Horn purchased a sample of the CBD product, had it tested, and found that, contrary to the claim, it did contain THC—enough, the lawsuit alleges, to cause a THC level in his urine of 29 nanograms per milliliter (ng/mL). That’s double the amount that typically triggers a positive result, says Sample at Quest Diagnostics.
Mislabeled CBD products are a growing problem for American workers, Sample believes. “It’s buyer beware,” he says. “There’s not always truth in labeling on the products.”
And he believes those high levels could be due in part to how THC levels are measured in hemp plants. While those plants are supposed to contain no more than 0.3 percent THC, that’s based on the dry weight of the plant. “But dry weight doesn’t necessarily equate to what’s in the finished product,” Sample says.
Plus, he says, in some cases that percentage is based on the weight of the whole plant, or on the weight of the buds or flowers, which tend to have more THC.
Adding to the confusion is that each state can determine how it samples and tests hemp plants for THC content, says Aline DeLucia, senior policy analyst for the National Association of State Departments of Agriculture. When sampling the hemp plant, “the closer you get to the flower, the higher the THC content. So some states collect the top 6 inches of the plant, while others do it differently,” DeLucia says. But “everybody is onboard that we need some kind of uniformity.”
And once CBD is turned into a “finished” product, such as an oil, a lotion, a tincture, a pill, or a vape liquid, few states dictate how those should be tested for THC, save for Oregon and soon Vermont. State agriculture departments, DeLucia says, don’t have jurisdiction over testing these products for safety.
Last, some states allow medical CBD products obtained through permitted channels to contain more than 0.3 percent THC. For example, the cutoff in Georgia and Virginia is 5 percent, Sample says, a level that is definitely high enough to cause impairment and a failed drug test.
Best bet: To increase the likelihood that a product doesn’t have more THC than claimed, look for a manufacturer that can provide a Certificate of Analysis, or COA, for its product. That document shows the results of a company’s testing for THC, CBD, and various contaminants. Though that testing is voluntary (except in Indiana and Utah) and the results aren’t confirmed by independent experts, for now it’s the best information available. If a store or website can’t provide you with a COA, look for another product. Read more about how CBD products are tested.