Ask Doctor Leigh: Can cannabis affect male fertility?

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Using cannabis can have a big impact on your physical and mental health—for better, and sometimes for worse. That’s why it’s important to consult a healthcare provider before experimenting.

Here at GreenState, cannabis clinician Dr. Leigh Vinocur is here to answer your questions on healthy living with cannabis.

Editor’s Note: The answer to this question is meant to supplement, not replace, advice, diagnoses, and treatment from a healthcare provider.  Always consult a medical professional when using cannabis for medicinal purposes, and do not disregard the advice of your healthcare provider because of anything you may read in this article. 

Q: Can cannabis affect male fertility?

A: Unfortunately, the answers are not so clear cut and there have been conflicting studies on this topic. Prior studies, mostly done on animals such as rats, have shown cannabis can cause testicular shrinkage or atrophy, as well as reduced libido and sexual function, but the good news is that this has not been seen very much in human trials.

A Danish study published in the American Journal of Epidemiology reported poorer quality semen with a 28% reduction in sperm concentration and a 29% reduction in total sperm count in study participants ages 18-28 who used cannabis more than once a week.

Another study published in 2019 in Reproductive Epidemiology, contradicts the 2015 Danish study described above. Here the participants from a fertility clinic who admitted to smoking cannabis appeared to have a higher concentration of sperm when compared to participants that reported never using cannabis. However, since these patients were already seeing a fertility specialist this study population may not apply to everyone else and it was a relatively small number of study of patients.

Aside from concentration and total sperm count, there might be some concerns also with sperm motility, an important factor in male fertility. And with so many conflicting reports in 2019 the Journal of Urology published a review article looking at cannabis and male fertility.

They reviewed about 48 previously published studies looking at a variety of factors that affect male fertility. These include sperm shape, sperm motility and viability as well as fertilizing capacity. This review article concluded that cannabis MAY negatively impact male fertility and that more research is needed.

But this provides little help to those concerned and wondering what to do. And since the jury is still out, as a physician my recommendation is to err on the side of caution. That means have a frank discussion with your doctor, and if you are a man of reproductive age and you and your partner are trying to have a baby, try to cut back and or stop using cannabis during this time.  I even counsel my medical cannabis female patients to do the same during pregnancy. And if you are having trouble conceiving, make sure you see a medical professional who specializes in reproduction and fertility. Unfortunately, like many other questions and issues we face with medical cannabis, because of its federally illegal status, we still don’t have all the clinical research we need right now to make clearly decisive evidence-based recommendations.

Got cannabis questions? Ask Doctor Leigh. Send your questions to GreenState’s Assistant Editor Elissa Esher at and keep an eye out for new answers from Dr. Leigh Vinocur every month.

Dr. Leigh Vinocur is a board-certified emergency physician who also has a cannabis consulting practice for patients and industry. She is a member of the Society of Cannabis Clinicians and a graduate of the inaugural class, with the first Master of Science in the country in Medical Cannabis Science and Therapeutics from the University of Maryland School of Pharmacy.

The response to this question was not written or edited by Hearst. The authors are solely responsible for the content.

Leigh Vinocur, MD