Introduction: Cannabis sativa (hemp) seeds are popular for their high nutrient content, and strict regulations are in place to limit the amount of potentially harmful phytocannabinoids, especially D9-tetrahydrocannabinol (D9-THC). In
Canada, this limit is 10 lg of D9-THC per gram of hemp seeds (10 ppm), and other jurisdictions in the world follow similar guidelines.
Materials and Methods: We investigated three different brands of consumer-grade hemp seeds using four different procedures to extract phytocannabinoids, and quantified total D9-THC and cannabidiol (CBD).
Discussion: We discovered that D9-THC concentrations in these hemp seeds could be as high as 1250% of the legal limit, and the amount of phytocannabinoids depended on the extraction procedure employed, Soxhlet
extraction being the most efficient across all three brands of seeds. D9-THC and CBD exhibited significant variations in their estimated concentrations even from the same brand, reflecting the inhomogeneous nature of seeds and variability due to the extraction method, but almost in all cases, D9-THC concentrations were higher than the legal limit. These quantities of total D9-THC may reach as high as 3.8mg per gram of hemp seeds, if one were consuming a 30-g daily recommended amount of hemp seeds, and is a cause for concern for potential toxicity. It is not clear if these high quantities of D9-THC are due to contamination of the seeds, or any other reason.