Will CBD Make Me Fail a Drug Test?

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From dog treats to lube, toothpicks to hair gel, you can find CBD in almost anything. While there’s a lot to love about this trendy product, there’s one not-so-lovable, seldom advertised aspect of CBD: It can make you fail a drug test.

Dr. Leigh Vinocur, a practicing physician and member of the Society of Cannabis Clinicians, told GreenState some of her patients have failed drug tests after using CBD for medical reasons, and employees around the country have run into the same issue. Though the cases are rare, enough research has confirmed CBD can trigger a false positive that some at-home drug tests have gone so far as to print a warning that the test may react with cannabidiol in their user manual or packaging.

Vinocur said that the most common reason her patients have failed drug tests after using CBD is that the test reacted to the THC contained in full-spectrum CBD products. 

RELATED: CBD or THC? Common drug test can’t tell the difference

“Right now, federal law says CBD products must contain 0.3% THC or less,” Vinocur told GreenState. “But CBD is not specifically regulated by the FDA, so there’s always a slight possibility there is more THC in your full spectrum CBD products than you think.”

The good news—false test results caused by full-spectrum CBD are an easy fix. You can always make sure you are purchasing CBD from a reputable company by checking their product analytics to ensure they contain less than 0.3 percent THC.

Or, to be safe, Vinocur suggests her patients only use CBD isolate (i.e. CBD products containing pure CBD – no terpenes or THC) two to three weeks before taking a drug test. A recent study by the University of Utah Health Sciences Center at Salt Lake City, in which researchers inserted CBD isolate into three different batches of urine samples and tested each with three popular THC screening tests, showed it yielded no false positives.

The bad news—CBD isolate isn’t entirely fool-proof. Even after using only CBD isolate for weeks, one of Vinocur’s patients continued to fail a urine drug screen. It isn’t common, and there is too little research on cannabis drug testing to definitively explain why. But, for those who do find themselves in this situation, Vinocur said the reason may be one of two things: either the test is mistaking the CBD in your pee for THC, or CBD has morphed into THC in your stomach.

“If you look at the chemical structure of CBD and THC, they’re very similar,” Vinocur said. “This means two things: first, there’s a chance tests can mistake CBD for THC, and second, it’s surprisingly easy for CBD to transform into THC. Acid can convert CBD into THC, and we have acid in our stomachs, so it might be possible that CBD could convert to THC in a person’s stomach, especially if their stomach is highly acidic.”

Though the idea is controversial and scarcely researched, there is a chance this bizarre transformation might be involved in another cannabis mystery: the “high” some people experience after using CBD products. Marisa Zeppieri-Caruana, founder of the award-winning health blog, “LupusChick,” who consistently uses and advertises CBD products for chronic pain, told GreenState she felt like she was feeling the classic effects of THC after taking a quarter of the recommended amount of a reputable CBD oil containing less than 0.3 percent THC.

“Within a few minutes after I put the oil under my tongue, everything felt like it was in slow motion,” Zeppieri-Caruana said. “My reactions were slow and I wasn’t in control over myself – like there was a separation between me and my body… I definitely wouldn’t have been able to drive.”

RELATED: Why do I feel high on CBD? 4 Reasons and what to do about it

If you’re still not passing a drug test after using CBD isolate for medical purposes, Vinocur suggests having a transparent conversation with your employer about your health and, if possible, getting a note from your doctor explaining how CBD could interfere with your results. Keep in mind, though, that some employers (such as the Department of Transportation) will not accept CBD use as an excuse for failing a drug test.

Elissa Esher is Assistant Editor at GreenState. Her work has also appeared in The Boston Guardian, Brooklyn Paper, Religion Unplugged, and Iridescent Women. Send inquiries and tips to elli.esher@hearst.com.