Daily CBD Supplement Use Can Trigger Positive Drug Tests for Athletes
Ten weeks of daily broad-spectrum CBD supplementation produced detectable levels of WADA-prohibited cannabinoids in urine, with concentrations increasing after exercise.
Quick Facts
What This Study Found
Daily use of a broad-spectrum CBD product (150 mg/day) led to detectable urinary concentrations of CBG in 42% and CBDV in 68% of pre-exercise samples, rising to 74% and 84% post-exercise, despite no THC detection at any timepoint.
Key Numbers
150 mg/day CBD for 10 weeks; n=36; CBG detected in 42→74% of samples pre-to-post exercise; CBDV in 68→84%; significant post-exercise increases for CBD (p=0.043), CBG (p=0.0023), CBDV (p=0.033); zero THC detection
How They Did This
Randomized, placebo-controlled trial with 36 healthy individuals (31 CBD, 5 placebo) self-administering broad-spectrum CBD or placebo for 10 weeks, followed by a 90-minute moderate-intensity exercise bout with blood and urine sampling.
Why This Research Matters
Athletes using legal broad-spectrum CBD products may unknowingly test positive for prohibited cannabinoids under WADA rules, and exercise amplifies this risk — a critical finding for competitive sport.
The Bigger Picture
As CBD use grows among athletes for recovery and wellness, this study reveals an underappreciated anti-doping risk from trace cannabinoids in broad-spectrum products that regulators and sports organizations need to address.
What This Study Doesn't Tell Us
Small placebo group (n=5); single CBD product tested; exercise protocol was moderate intensity only; did not assess high-intensity or repeated exercise effects; short-term study without washout period assessment.
Questions This Raises
- ?Would isolate CBD products avoid this risk entirely?
- ?How long after stopping supplementation do prohibited cannabinoids remain detectable?
- ?Does exercise intensity correlate with cannabinoid release?
Trust & Context
- Key Stat:
- Evidence Grade:
- Randomized placebo-controlled design with objective biomarker outcomes, though limited by small sample size and single product tested.
- Study Age:
- Published 2026; reflects current CBD product formulations and WADA prohibited list.
- Original Title:
- Daily Use of a Broad-Spectrum Cannabidiol Supplement Produces Detectable Concentrations of Cannabinoids in Urine Prohibited by the World Anti-Doping Agency: An Effect Amplified by Exercise.
- Published In:
- Medicine and science in sports and exercise, 58(1), 121-131 (2026)
- Authors:
- Gillham, Scott H(2), Cole, Paige L, Owens, Daniel J, Chester, Neil, Bampouras, Theodoros M, McCartney, Danielle, Gordon, Rebecca, McGregor, Iain S, Close, Graeme L
- Database ID:
- RTHC-08278
Evidence Hierarchy
Frequently Asked Questions
Can CBD supplements cause a failed drug test in sports?
Yes — this study showed that broad-spectrum CBD products containing trace amounts of other cannabinoids like CBG and CBDV can produce detectable levels of WADA-prohibited substances in urine, even though THC was never detected.
Does exercise affect CBD drug test results?
Yes. Exercise significantly increased urinary concentrations of multiple cannabinoids including CBG and CBDV, likely due to release from fat tissue during physical activity.
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Cite This Study
https://rethinkthc.com/research/RTHC-08278APA
Gillham, Scott H; Cole, Paige L; Owens, Daniel J; Chester, Neil; Bampouras, Theodoros M; McCartney, Danielle; Gordon, Rebecca; McGregor, Iain S; Close, Graeme L. (2026). Daily Use of a Broad-Spectrum Cannabidiol Supplement Produces Detectable Concentrations of Cannabinoids in Urine Prohibited by the World Anti-Doping Agency: An Effect Amplified by Exercise.. Medicine and science in sports and exercise, 58(1), 121-131. https://doi.org/10.1249/MSS.0000000000003842
MLA
Gillham, Scott H, et al. "Daily Use of a Broad-Spectrum Cannabidiol Supplement Produces Detectable Concentrations of Cannabinoids in Urine Prohibited by the World Anti-Doping Agency: An Effect Amplified by Exercise.." Medicine and science in sports and exercise, 2026. https://doi.org/10.1249/MSS.0000000000003842
RethinkTHC
RethinkTHC Research Database. "Daily Use of a Broad-Spectrum Cannabidiol Supplement Produce..." RTHC-08278. Retrieved from https://rethinkthc.com/research/gillham-2026-daily-use-of-a
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.