Some hemp seeds contain far more THC than the legal limit allows | Research

The takeaway

Testing of consumer-grade hemp seeds found THC levels up to 1,250% above Canada's legal limit, raising concerns about unintentional THC exposure from food products.

Read this if you eat hemp seeds regularly and want to know whether they could contain meaningful amounts of THC.

THC levels up to 1,250% above the legal limit in consumer hemp seeds

What the researchers found

Researchers tested three brands of consumer-grade hemp seeds using four different extraction methods to measure THC and CBD content. Across nearly all brands and methods, THC levels exceeded Canada's legal limit of 10 micrograms per gram.

The most efficient extraction method (Soxhlet extraction) revealed THC concentrations as high as 1,250% of the legal limit. If someone consumed the recommended 30 grams of hemp seeds per day, they could potentially ingest up to 3.8 milligrams of THC, a dose that could produce noticeable effects in sensitive individuals.

THC and CBD levels varied significantly even within the same brand, reflecting the inhomogeneous nature of hemp seeds. It remained unclear whether the high THC levels were due to seed contamination from contact with THC-rich plant parts, or some other factor.

Why it matters

Hemp seeds are widely marketed as a health food, and many consumers have no idea they could contain meaningful amounts of THC. For people who are drug tested, are sensitive to THC, or are giving hemp seeds to children, these findings raise practical safety questions about a product many consider completely benign.

The numbers in context

Legal limit in Canada: 10 micrograms of THC per gram of hemp seeds. Maximum THC found: up to 1,250% of legal limit. Potential daily THC intake from 30g serving: up to 3.8 mg. Three brands tested with four extraction methods each.

How the study worked

Three brands of consumer-grade hemp seeds were purchased and tested using four different extraction procedures: Soxhlet extraction, sonication, maceration, and reflux. Total THC and CBD were quantified for each brand using each method. The researchers compared results across methods to determine which most accurately captured total cannabinoid content.

What this study cannot tell us

Only three brands were tested, which limits generalizability. The study used laboratory extraction methods that may not reflect how THC is absorbed during normal digestion. The actual bioavailability of THC from hemp seeds during eating could be lower than what extraction methods capture. No human subjects were involved to test actual effects.

How to read the evidence

This is a small laboratory study testing only three brands with no human subjects, providing preliminary evidence of a potential food safety concern.

When this study was published

Published in 2017. Hemp food regulations and testing methods may have been updated since.

The bigger picture

This study highlights a gap between food safety regulations and actual cannabinoid content in commercial products. As hemp-derived foods proliferate globally, the variability in cannabinoid content and the dependence of test results on extraction methods suggest that current quality control may not be catching all contaminated products.

Questions still open

How much THC from hemp seeds is actually absorbed during normal digestion? Could regular hemp seed consumption cause a positive drug test? Are regulatory testing methods for hemp seeds adequately capturing true THC content?

Common questions

Can hemp seeds get you high?

At the levels found in this study, a daily serving could deliver up to 3.8 mg of THC. While this is a low dose compared to recreational use, it could potentially produce mild effects in sensitive individuals, particularly those with no THC tolerance.

Could eating hemp seeds cause a failed drug test?

The study did not test this directly, but previous research has shown that consuming hemp foods can occasionally produce positive urine drug screens, particularly with frequent consumption of products containing higher-than-expected THC levels.

Read the original research

Cannabis sativa (Hemp) Seeds, Δ9-Tetrahydrocannabinol, and Potential Overdose.

Cannabis and cannabinoid research, 2(1), 274-281

View on PubMed ↗Publisher’s paper ↗

Citation

Yang, Yi; Lewis, Melissa M; Bello, Angelica M; Wasilewski, Ewa; Clarke, Hance A; Kotra, Lakshmi P. (2017). Cannabis sativa (Hemp) Seeds, Δ9-Tetrahydrocannabinol, and Potential Overdose.. Cannabis and cannabinoid research, 2(1), 274-281. https://doi.org/10.1089/can.2017.0040