Controlled Human Study Finds Hemp Seed Oil Produced Measurable Urinary THC Metabolites in 93.5% of Samples
- A controlled study at Ankara University found that repeated oral consumption of hemp seed oil produces detectable THC metabolites in urine, with 93.5% of samples from oral consumers testing positive.
- The study involved 15 volunteers divided into groups consuming hemp oil orally, applying hemp oil topically, or consuming hemp seeds, with urine samples collected over 10 days and analyzed using advanced chromatography techniques.
- Oral consumption of hemp seed oil resulted in the strongest and most persistent THC metabolite presence, mainly delta-8 THC-COOH, with concentrations plateauing after six days, while topical application showed minimal effects.
- The findings highlight the need for caution when interpreting low-level positive THC results in drug testing and suggest that differentiating between delta-8 and delta-9 THC metabolites can help identify the source of cannabinoid exposure.
A controlled human study found that repeated consumption of hemp seed oil can produce measurable THC metabolites in urine, with the compounds detected in 93.5% of samples collected from participants who consumed the oil.
The study, published in Forensic Science International, was conducted by researchers at Ankara University in Türkiye. Researchers said the findings could be important when interpreting low-level THC results in forensic and drug-testing settings.
Researchers analyzed 22 hemp seed oils and 12 hemp seed products before conducting a controlled administration study involving 15 healthy volunteers. Participants were divided into three groups of five, receiving hemp oil orally, applying hemp oil to the skin or consuming hemp seeds.
Urine samples were collected over 10 days and analyzed using an isomer-specific liquid chromatography-tandem mass spectrometry method capable of distinguishing metabolites associated with delta-8 THC and delta-9 THC.
Repeated oral consumption of hemp seed oil produced by far the strongest and most persistent results.
Total THC-COOH, a major THC metabolite commonly measured in urine testing, was detected in 72 of 77 urine samples collected from the oral hemp oil group, or 93.5%.
Concentrations remained relatively low. The highest median total THC-COOH concentration was 3.91 nanograms per milliliter, while the highest individual concentration recorded was 4.52 nanograms per milliliter. Researchers observed that levels began showing a plateau-like pattern after the sixth day.
Eating hemp seeds also resulted in repeated THC metabolite detections, although concentrations were lower. Applying hemp oil to the skin produced the weakest and least consistent results.
Researchers also found that delta-8 THC-COOH was more prevalent than delta-9 THC-COOH among participants consuming the oil orally. The ratio between the two metabolites ranged from 1.92 to 8.83.
The authors said the findings demonstrate that consumption of hemp seed products can result in measurable urinary cannabinoid levels even without traditional marijuana use.
They said the results support greater caution when interpreting low-level positive cannabinoid findings and indicate that distinguishing between delta-8 and delta-9 metabolites may help forensic toxicologists determine the potential source of a positive result.