A standardized cannabis extract administered to Wistar rats at doses up to 56 mg/kg showed no significant effects on sex hormones, sperm quality, female fertility, blastocyst implantation, or embryonic development.
Reproductive toxicology researchers and clinicians advising on cannabis use and fertility.
No fertility effects at any dose tested
What the researchers found
None of the tested doses (0.28 to 56 mg/kg) significantly affected sex hormone levels in male or female rats. Male organ morphology and sperm characteristics were unaffected. Female fertility, blastocyst implantation, and early embryonic development were normal across all doses up to 7 days post-pregnancy confirmation. No direct toxic effects on the embryo were observed.
Why it matters
Concerns about cannabis effects on fertility are common among reproductive-age users. This preclinical study provides data that a standardized cannabis extract did not impair fertility markers in rats, though animal results require caution when extrapolating to humans.
The numbers in context
Doses tested: 0.28, 2.8, 28, and 56 mg/kg body weight. 7 groups of 20 animals each. No significant changes in sex hormones, sperm characteristics, fertility, or blastocyst implantation at any dose.
How the study worked
Seven groups of 20 Wistar rats each received different doses of a standardized Cannabis sativa extract (160.32 mg/mL). Assessments included clinical exams, biochemistry, organ weights, sperm production and morphology, histopathology, and female fertility/implantation outcomes per nonclinical toxicology guidelines.
What this study cannot tell us
Animal study with uncertain human translation. Rat reproductive biology differs from human in important ways. Short duration of exposure may miss effects that emerge with chronic use. Extract composition may not represent recreational products.
How to read the evidence
Well-structured preclinical study following standard toxicology guidelines with multiple dose levels, but animal results have limited direct applicability to human reproductive health.
When this study was published
2025 publication
The bigger picture
This study contrasts with some previous research suggesting THC can disrupt reproductive hormones. The use of a full-spectrum cannabis extract rather than isolated THC may account for differences, or the doses may have been insufficient to produce effects.
Questions still open
- Would chronic exposure over longer periods produce different results? Do specific cannabinoid ratios within full-spectrum extracts affect fertility outcomes? How do these animal findings compare with epidemiological data on cannabis and human fertility?
Common questions
Does cannabis affect fertility?
What doses were tested?
Read the original research
Cannabis sativa extract and fertility: Preclinical evaluation in male and female Wistar rats.
Reproductive toxicology (Elmsford, N.Y.), 136, 108982
Citation
Costa, Alana C; Pereira, Cícero A C; Gasparotto, Arquimedes; Garcia, Alana A K; Lourenço, Emerson L B; Joaquim, Helena P G. (2025). Cannabis sativa extract and fertility: Preclinical evaluation in male and female Wistar rats.. Reproductive toxicology (Elmsford, N.Y.), 136, 108982. https://doi.org/10.1016/j.reprotox.2025.108982
Explore the wider topic
- How to Talk to Your Teenager About Weed (Without Losing Them)
- My Kid's Friends Smoke Weed: A Parent's Guide
- I Smoke Weed But Don't Want My Kids To: Navigating the Hypocrisy
- Quitting Weed as a Parent: Why It Is the Hardest and Most Important Quit
- Quitting Weed as a Teen or Young Adult
- My Kid Is Smoking Weed: A Parent's Guide