A 90-day toxicology study found a CBD-dominant hemp extract (55-75% CBD) was non-mutagenic and well-tolerated in rats, with a no adverse effect level of about 186 mg/kg/day.
Read this if you use CBD products and want to understand the formal safety testing behind them.
186 mg/kg/dayNo observed adverse effect level for CBD-rich hemp extract in 90-day rat study
What the researchers found
HempChoice Hemp Oil Extract (55-75% CBD, 1-15% other cannabinoids, 1-15% terpenes) was tested across multiple safety studies. It was non-mutagenic in Ames and micronucleus tests. In a 14-day study, doses up to 96 mg/kg/day were well tolerated. In the 90-day study, no treatment-related changes were found in body weight, food consumption, behavior, or eye health. Some hematology and clinical chemistry changes occurred but were within normal range and reversed during the 28-day recovery period. Liver histopathology showed adaptive (not adverse) changes that also resolved. The NOAEL was 185.90 mg/kg/day.
Why it matters
As CBD products proliferate, formal toxicological safety data is essential for regulatory decisions. This study provides the type of standardized safety assessment (GLP-compliant) that regulators require for novel food or dietary supplement approval.
The numbers in context
- CBD content: 55-75% of extract
- Other phytocannabinoids: 1-15%
- Terpenes: 1-15%
- 14-day range-finding: tolerated up to 96.03 mg/kg/day
- 90-day NOAEL: 185.90 mg/kg/day
- 28-day recovery period: all changes reversed
- Non-mutagenic in Ames and micronucleus tests
How the study worked
Standard battery of toxicology studies: bacterial reverse mutation (Ames) test, mammalian cell micronucleus test, 14-day range-finding study, and 90-day repeated dose study with 28-day recovery in Sprague-Dawley rats. Assessed body weight, food consumption, clinical observations, ophthalmology, hematology, clinical chemistry, gross pathology, and histopathology.
Who was studied
Male and female Sprague-Dawley rats
What this study cannot tell us
Rat toxicology may not perfectly predict human responses. The extract is a specific commercial product; other CBD products may have different compositions and safety profiles. Long-term effects beyond 90 days not assessed.
How to read the evidence
Standard regulatory toxicology battery in rats. Strong methodology for safety assessment but limited to a single commercial product.
When this study was published
Published in 2023. Contributes to the growing body of formal CBD safety data for regulatory review.
The bigger picture
Regulatory bodies worldwide are evaluating CBD as a novel food ingredient. Studies like this provide the standardized safety data needed for informed regulatory decisions, complementing the clinical and epidemiological evidence.
Questions still open
- How does this NOAEL translate to recommended human doses?
- Would longer-term exposure reveal additional safety concerns?
- Do other CBD products with different terpene and cannabinoid profiles have similar safety margins?
Read the original research
Toxicological safety assessment of HempChoice® hemp oil extract; a proprietary extract consisting of a high concentration of cannabidiol (CBD) in addition to other phytocannabinoids and terpenes derived from CannabissativaL.
Heliyon, 9(6), e16913
Citation
Dziwenka, Margitta; Coppock, Robert; Davidson, Michael H; Weder, Marc A. (2023). Toxicological safety assessment of HempChoice® hemp oil extract; a proprietary extract consisting of a high concentration of cannabidiol (CBD) in addition to other phytocannabinoids and terpenes derived from CannabissativaL.. Heliyon, 9(6), e16913. https://doi.org/10.1016/j.heliyon.2023.e16913