The Emerging Link Between THC & Fertility
As cannabis use becomes more normalized, emerging research is drawing attention to its potential impact on reproductive health. Specifically, regular use of THC (tetrahydrocannabinol)—the primary psychoactive compound in cannabis—may negatively affect fertility for both individuals who menstruate and those who produce sperm. While further studies are needed, current findings suggest that THC and fertility may be more closely connected than previously understood.
How THC Affects the Menstrual Cycle and Hormone Regulation
A pivotal 2021 study conducted by the Oregon National Primate Research Center at Oregon Health & Science University explored the effects of daily THC consumption on menstrual cycles and reproductive hormone levels in non-human primates (Ryan et al., 2021). Over a three-month period, eight subjects were given gradually increasing doses of THC edibles, reaching a maximum of 2.5 mg—comparable to typical human dosage escalation patterns.
The results were significant:
As THC dosage increased, menstrual cycles became irregular and prolonged.
Subjects showed increased levels of follicle-stimulating hormone (FSH)—a key hormone that regulates ovarian function.
These disruptions in cycle regularity and hormone levels suggest a potential cause-and-effect relationship between THC use and reproductive hormone imbalance. While this study was conducted in non-human primates, it lays the groundwork for future human studies examining cannabis and menstrual health.
THC and Sperm Health: What the Research Says
THC’s effects on sperm parameters are also under increasing scientific scrutiny. A 2021 prospective study involving 409 individuals undergoing fertility evaluation found notable differences in semen quality based on cannabis use history (Hehemann et al., 2021):
17% of participants were current cannabis users; 25% had used it in the past.
Current and past users were more likely to show abnormal sperm morphology, specifically poor shape and structure.
Users also had a higher likelihood of producing lower semen volume than the World Health Organization’s reference standards.
Interestingly, the same study found higher sperm motility (movement ability) among cannabis users, suggesting that THC may not universally impair all aspects of semen quality. However, the overall findings lean toward a detrimental impact on male fertility, particularly regarding morphology and volume.
Conclusion: Proceed with Caution
While cannabis may offer certain therapeutic or recreational benefits, individuals trying to conceive should be mindful of the emerging evidence linking THC to fertility challenges. The effects may differ based on dosage, frequency, and individual biology—but the potential for hormone disruption and impaired reproductive function is significant enough to warrant caution.
As research evolves, healthcare providers may soon offer clearer guidelines for THC use and reproductive planning. In the meantime, those concerned about their fertility should consider speaking with a licensed medical provider before using cannabis products regularly.
References
Hehemann, M. C., Raheem, O. A., Rajanahally, S., Holt, S., Chen, T., Fustok, J. N., Song, K., Rylander, H., Chow, E., Ostrowski, K. A., Muller, C. H., & Walsh, T. J. (2021). Evaluation of the impact of marijuana use on semen quality: A prospective analysis. Therapeutic Advances in Urology, 13, 175628722110324. https://doi.org/10.1177/17562872211032484
Ryan, K. S., Mahalingaiah, S., Campbell, L. R., Roberts, V. H. J., Terrobias, J. J., Naito, C. S., Boniface, E. R., Borgelt, L. M., Hedges, J. C., Hanna, C. B., Hennebold, J. D., & Lo, J. O. (2021). The effects of delta-9-tetrahydrocannabinol exposure on female menstrual cyclicity and reproductive health in rhesus macaques. F&S Science, 2(3). https://doi.org/10.1016/j.xfss.2021.05.001
