Can Hemp Seed Oil Cause a Failed Drug Test? Uncovering The Truth

Many people get nervous when they have to take a drug test, even if they haven’t used or consumed any illicit substances.

There’s even more concern about positive drug tests for cannabis use now that CBD and hemp-derived products are so popular. That concern even extends to the consumption of hemp seed oil, a dietary supplement commonly used as a source of essential fatty acids.

The good news: hemp seed oil (and other products made from the seeds) shouldn’t cause any problems. There’s no psychoactive THC in the seeds of hemp plants.

The bad news: there could be cross-contamination during the processing of the seeds, leading to the inadvertent presence of trace amounts of THC in products produced from hemp seeds. And the news is even more troubling for those using CBD extracted from the plants themselves.

Experts say that CBD use can indeed cause a failed drug test, although the likelihood depends on factors that include how often the products are used, dosage levels, how an individual’s body metabolizes the THC content found in most of the products, and the type of CBD that’s used.

However, there’s only about a 10% chance that those who consume low to moderate doses of hemp oil, hemp food products, or CBD products will test positive— and there are ways to be sure you won’t have to worry about the test at all.

Let’s look deeper into the subject.

Why Would Hemp Products Cause a Failed Test?

Most modern drug screenings look for signs of illegal or regulated substances, including marijuana.

Weed is a product of the cannabis plant and not the hemp plant, but hemp and cannabis plants are both members of the cannabis sativa family. They’re close relatives that contain virtually all of the same plant compounds — including psychoactive THC (tetrahydrocannabinol) and non-psychoactive CBD (cannabidiol).

The important difference is in the levels of each cannabinoid. Marijuana plants generally contain high levels of THC and low levels of CBD, while hemp plants contain very little THC and much higher amounts of cannabidiol. That’s why the CBD products sold in stores and online are derived from hemp and not cannabis plants.

Importantly, though, there is a small amount of THC in most hemp and CBD products. British law allows a minuscule 0.2% THC concentration in retail cannabidiol products; the US Food and Drug Administration (FDA) and regulatory bodies in most European nations set the limit at 0.3%.

That’s not enough THC to get you high — but in some circumstances, it might be enough to trigger a positive result on a cannabis drug test.

How Do They Test for Marijuana Use?

The most common method used to check for signs of cannabis use is a urine drug test. Two methods are commonly used to analyze the urine sample.

A cannabis immunoassay test, or in user-friendly terms, a “point-of-care” test, is done immediately and takes just minutes. This test uses antibodies that react with THC and one of its metabolites, THC-COOH. If the concentration of either substance in the urine sample is above a “cutoff level” (typically 50 nanograms per milliliter), it’s assumed to be a positive result.

However, immunoassay tests aren’t always reliable. They’re known for returning false positive or false negative results.

Positive tests are generally sent to a lab for confirmation with a more accurate (and more expensive) gas chromatography/mass spectrometry (GC/MS) test, which uses a lower cutoff level. If the level of either THC or THC-COOH is above that level (typically 15 or 20 ng/mL), it confirms the positive test result.

CBD products, as well as hemp seed oil which has been contaminated during processing, are more likely to trigger a positive result on an immunoassay test because of its higher cutoff level. There have been instances, though, when the products have triggered a positive result on the lab test as well.

Research on Hemp, CBD, and Drug Testing

The most often-cited study on THC and THC-COOH levels related to hemp seed oil was published in the July/August 1997 issue of the Journal of Analytical Toxicology.

The study reported that one person who had purchased the oil at a Miami, Florida store and used it every day for nearly a month tested positive for cannabis use on both immunoassay and GC/MS tests. Another person consumed a large number of hemp seed oil capsules (also purchased at a Miami store) at a single time and then tested positive for THC on both tests.

A previous report in the same journal documented positive cannabis test results for an individual who had eaten a hemp seed snack. And a study published in that journal more recently, in 2023, investigated the likelihood of a positive test when using CBD.

Researchers had subjects use three different types of CBD products consumed via oral ingestion and with the use of a vaporizer. It’s important to note that the products were sourced from cannabis plants and contained slightly more than the amount of THC that’s legal in Britain and the U.S. (0.39%, rather than 0.3% or 0.2%).

The scientists, though, say their findings remain important. Three of the 18 study participants, all of whom had vaped the CBD, tested positive for cannabis use on a lab test using a 20 ng/mL cutoff. Since the amount of THC in the products wasn’t substantially higher than the amount in most commercially-available CBD products, they say,

“It is possible that hemp products containing low amounts of THC may produce a cannabis-positive urine drug test.”

Avoiding a Positive Drug Test Result

So how do you make sure you won’t trigger a urine test when using hemp products? The conclusions and best advice differ for those who use hemp seed oil and those who consume CBD products.

Hemp Seed Oil

There’s no practical way for a consumer to know whether hemp oil or other products produced from the seeds of the hemp plant may have been contaminated during the production process. Sadly, that means there’s no foolproof method you can use to avoid inadvertent consumption of THC.

However, the research indicates that THC drug tests are most likely to be triggered either with very large doses of hemp seed oil or long-term use of large amounts. If you may be facing a drug test, the best approach to hemp products is to discontinue their use at least a month before testing and/or to avoid using heavy doses.

CBD Products

The same advice would make sense for regular users of CBD products like oil, capsules, edibles, vape juice, and perhaps even creams. But there’s an even better way to ensure that CBD use won’t trigger a cannabis urine test.

Here’s the background you need to know first. CBD products are produced in three different forms.

• Full-spectrum CBD: These products contain all of the cannabinoids and other plant compounds sourced from hemp. They include the low levels of THC that may be problematic when taking a urine test.
• Broad-spectrum CBD: These products are almost the same as full-spectrum CBD, but the THC has been removed during processing. The extraction process may still leave trace amounts of THC in the products, though.
• CBD Isolate: These products contain only cannabidiol, with no trace of THC remaining.

That should make the “safe route” obvious. CBD isolate products are THC-free and eliminate the possibility that you’ll trigger a positive test for cannabis use. And broad-spectrum CBD products dramatically lower the chances that you’ll test positive.

Full-spectrum CBD products are the most effective of the three, but all contain roughly the same amount of cannabidiol and provide almost all of the same benefits. Purchasing only CBD isolate is the only reliable way to be sure you won’t be surprised when faced with a surprise drug test.

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