Pure CBD Does Not Trigger Positive Drug Tests for Weed, New Study Shows
While some evidence shows that CBD can convert to THC in the stomach, a new study suggests that pure CBD will not cause positive drug test results for weed.
Published on November 19, 2019

If you take federally legal CBD products, can you fail a drug test looking for weed use? A study published earlier this month found that many CBD products will create positive drug test results. But let's make one thing clear: Pure, pharmaceutical-grade CBD will not.

The study, conducted by researchers working with the Johns Hopkins University School of Medicine, was published in the November edition of the Journal of Analytical Toxicology

“The impact of CBD exposure on urine drug testing has not been well studied,” the researchers wrote. To better understand how CBD could affect drug screens, they gave human subjects 100mg CBD orally and through a vaporizer, then tested the subjects’ urine samples just before administration, then again each subsequent day for five days after CBD administration.

Here’s what they discovered. First, CBD products containing even trace amounts of THC can produce false positives for weed use on urine tests. Since pretty much every CBD product available right now comes from hemp — and hemp is just cannabis with miniscule amounts of THC — some of that THC ends up in the final product. While CBD is marketed as a non-intoxicating cannabis product, any THC in a CBD product could have disastrous results, especially for people working in safety sensitive positions or under federal contracts, which regularly test for THC.

THC-tainted CBD products have already led to at least one lawsuit. Earlier this year, a truck driver claimed a supposedly pure CBD product containing no THC sold in Colorado caused a false positive on a drug test. The trucker said he never consumed marijuana, only the products he believed were made entirely of CBD. The test result not only cost him his job, but his commercial driver's license (CDL), as well. 

Gallery — Free the Tree and Let Us Be:

But, back to the study. The second, and probably most insightful discovery, was that pure CBD only triggered a positive test result in 1 out of 218 urine samples. The single positive result may have been a fluke, though some evidence suggests even pure CBD may still show up hot on drug tests.

How could non-intoxicating CBD show up as THC on a test? Some scientists suspect CBD can convert to THC when exposed to acid. Scientists observed this CBD-to-THC conversion in lab settings, but observing the same thing in a natural acidic environment — like the human stomach — has never been proven. 

“These data indicate that acute dosing of pure CBD will not result in a positive urine drug test using current federal workplace drug testing guidelines,” the researchers wrote. “However, CBD products that also contain ∆9-THC may produce positive urine results for” THC metabolites. “Accurate labeling and regulation of ∆9-THC content in CBD/hemp products are needed to prevent unexpected positive drug tests and unintended drug effects.”

Regardless, all this means that urine tests for THC no longer reliably pinpoint whether someone consumed marijuana. Consuming hemp, which is cannabis that contains less than 0.3 percent THC by dry weight, can also produce positive test results for alleged weed use. When the US government federally legalized hemp late last year, it also inadvertently legalized THC — but only THC found in hemp. THC in marijuana, which is legally defined as cannabis with more than 0.3 percent THC by dry weight, remains a Schedule I drug at the federal level, the most restrictive category reserved only for substances that are supposedly addictive, dangerous, and offer no accepted medical use. 

And, for the record, the THC found in hemp is the same exact THC found in marijuana. The only difference between hemp’s THC and marijuana’s THC resides in largely arbitrary legal definitions.

Follow Randy Robinson on Twitter

Click to shop at our CBD store
Randy Robinson
Based in Denver, Randy studied cannabinoid science while getting a degree in molecular biology at the University of Colorado. When not writing about cannabis, science, politics, or LGBT issues, they can be found exploring nature somewhere in the Rocky Mountains. Catch Randy on Twitter and Instagram @randieseljay
Share this article with your friends!
By using our site you agree to our use of cookies to deliver a better experience.