Oh, the times, they are a changing… Medical Marijuana is now legal in 38 states, Washington DC, and Guam. Of those, recreational “Maryjane” is also legal in 19 states, including New Jersey. Societal benefits that have been claimed include the elimination of a formerly low-level crime, and the generation of tax dollars for the public good. Critics point to increased numbers of emergency room visits for marijuana intoxication, increased numbers of auto accidents, and possible long-term effects of the now more potent forms of “Weed” on the developing brain. Regardless of your opinion, there is no denying that Marijuana use is climbing internationally, in the US, and in the state of New Jersey.
While it is tempting to focus on Marijuana’s psychoactive effects from THC (∆9-tetrahydrocannabinol), it is important to recognize that there are endogenous cannabinoids which are generated in various sites in the body which bind to receptors in a number of organs including the brain and also including the testes. One theory behind THC’s reproductive effects is that THC may compete with endogenous cannibinoids in the testes, with a disruptive effect on sperm production. In fact endogenous cannabinoid receptors (CB1 and CB2) can be found in the hypothalamus, pituitary gland, Leydig cells (testosterone producing cells in the testes) Sertoli cells (cells that participate in sperm maturation and support in the testes) as well as in the vas deferens and on sperm cells (spermatozoa) themselves.
Cooper and Sloan et al (Lead author Thomas Walsh) published a report In the January 2022 AUA News entitled “Evaluation of the Impact of Marijuana Use on Semen quality.” The authors report on a prospective study looking at semen quality in men who reported present or past consumption of marijuana compared to “never-users”. According to the authors, multivariate logistic regression analysis showed that both current and past users demonstrated significantly increased odds of having abnormal strict morphology. Current users also had significantly increased odds of having below normal WHO reference semen volume as well as total motility.
The authors also referenced two recent European studies showing increased risk of poor sperm morphology and reduction in sperm concentration and total sperm count by Pacey et al in Human Reproduction 2014 p 1629 as well as Gundersen et al in 2015 American Journal of epidemiology p 473. The article concluded with their recommendation against marijuana use in men trying to conceive a pregnancy with their partners.
Continuing on this theme, a review in the 2018 European Urologic Focus by Hsiao and Clavijo (Apr;4(3):324-328) entitled “Adverse effects of Cannabis on Male Reproduction” reports a number of small cohort studies that show semen analysis parameters associate cannabis use with lower sperm concentrations. T
The review also references a 2006 study from Fertility and Sterility by Whan et al that tried to clarify the impact of THC on sperm function by incubating moving sperm with different concentrations of THC. Those authors showed that THC produced a dose-dependent reduction in the numbers of progressively motile sperm (2–21% reduction) and a significant inhibition of the spontaneous acrosome reaction.
Anecdotally, I have seen improvements in sperm capacitation results as reflected by the Cap-ScoreTM test with cessation of marijuana use. My recommendation to my male patients who are avid users is to reduce smoking to no more than weekly if possible, and not to expect improvement in sperm function or semen analysis results until they have reduced their intake for at least 3 months. In general, lifestyle changes including reduction in recreational substances, exercise, better diet, better sleep, better nutrition can all be beneficial to reproductive health.