How Cannabis Impacts Male Fertility? What The Latest Research Studies Reveal

male fertility cannabis

In recent years, there has been an increasing interest among the scientific community to explain how cannabis impacts male fertility.

This has to do with the fact that the dominant group of cannabis users is still young and middle-aged men. Basically, men in their reproductive years.

With the legalization of recreational marijuana use in some American states and Canada, there is a justified assumption that the number of male pot smokers will only rise in the near future.

So, what is the true correlation between cannabis and male fertility? Is weed good or bad for men’s reproductive health?

Limited research and no easy answer

We already know that legal substances like tobacco and alcohol (and some illegal ones, e.g. drugs) have a detrimental effect on both male and female reproductive health.

Another disturbing fact is that over the past 40 years, sperm count per milliliter of semen has declined for an astonishing 40%, or 1% for every passing year. Today’s men are half as fertile as their grandfathers were.

In this alarming epidemic of male infertility, where does marijuana stand?

The answer is not an easy one.

While studies about marijuana effects on sperm and male fertility have been limited, some previous studies suggest that cannabis has a negative impact on sperm quality.

The results of those studies show that cannabis reduces the amount of seminal fluid, total sperm count, and even indicate the abnormal motion behavior among remaining sperm cells.

Last year we wrote about this topic and covered some of the most prominent research papers that were available at the moment. The general conclusion was that there is a negative effect of cannabis use on sperm production, but only in the short run.

In other words, weed should only be avoided if a man is planning to start a family. That’s because it takes about three months for each sperm cell to be created. If a man undergoes cannabis abstinence for 3+ months, his new sperm cells shouldn’t be affected by previous cannabis consumption.

2019, and unexpected new findings

Now let’s put on hold all that we’ve mentioned so far. In February this year, a new study by the Harvard T. H. Chan School of Public Health in Boston was published in the journal Human Reproduction. Their findings were surprising, to say the least.

Contrary to their original hypothesis, scientists discovered that men who smoked cannabis at some point in their lives had significantly higher sperm concentrations than those who had never used marijuana before.

The researchers conducted a study among 662 men who were patients at the Massachusetts General Hospital Fertility Center in the period between 2000 and 2017. All men belonged to couples that had a problem with conception and were seeking help at a fertility clinic.

On average, the men were 36 years old, non-smokers, mostly Caucasians, with a college degree. They all provided a total of 1143 semen samples, while 317 men also provided blood samples that were used for the analysis of the reproductive hormones.

In order to gather information on the history of marijuana consumption, participants were asked to fill in a self-administered questionnaire.

More than half (55%) of the men reported having smoked marijuana (at least 2 joints) at some point in their lives. Among those participants, 44% said that they had used cannabis in the past, while 11% of them classified themselves as current cannabis users.

Before conducting an in-depth analysis, researchers hypothesized that marijuana consumption would be associated with worse semen quality. This was based on previous research findings, although most of those studies were conducted on animal models or on men with long histories of drugs, tobacco, and alcohol use.

Higher sperm count, lower FSH

Analysis of the semen sample showed that men who had smoked marijuana at some point had notably higher sperm concentration and lower serum FSH concentration than men who had never used marijuana.

FSH (Follicle-stimulating hormone) is a reproductive hormone that regulates testosterone levels and helps in the production of the Sertoli cells that are essential for sperm production (spermatogenesis) and correct function of the testicles.

This hormone at elevated levels could be linked to infertility, so lower FHS concentration generally means a good thing for spermatozoids (if not too low).

Jorge Chavarro, associate professor of nutrition and epidemiology at Harvard Chan School of Public Health and one of the coauthors of this study, admitted that his team was really surprised by the results they got.

“We spent a good two months redoing everything, making sure that there wasn’t any error in the data. We were very, very surprised about this.” Chavarro said in an interview with Time magazine.

Surprising as the results may be, it seems that scientists still don’t know what to make of them. They are pretty sure that smoking marijuana is not going to cure your infertility, but it appears that low levels of marijuana intake can improve the function of the testicles and lead to better sperm and reproductive hormone production.

When it comes to higher doses, marijuana has the completely opposite effect. This has been supported by all the previous studies on the topic of marijuana effects on sperm.

The most plausible explanation of these unexpected results is that men who have higher testosterone levels are more prone to risk-seeking behavior, which includes smoking cannabis for its psychoactive effects.

Basically, this would mean that men who already have better sperm quality tend to smoke more pot, not the other way around.

No general consensus

Confusing as it may be to have two different interpretations of the same results, the effect of marijuana intake on male fertility (and body in general) is still unclear and there is no evidence that the general consensus will be reached in the foreseeable future.

This just proves how complex cannabis and its health effects are, and how little we know about this incredible plant.

Maybe it’s better to leave the final word to aforementioned Jorge Chavarro when he says: “We could have found what we thought we were going to find, and maybe wouldn’t have been as surprised and would have ended up writing a very different paper. But the fact that we showed the exact opposite forced us to look very, very deeply into the marijuana health effects literature. There is not that much. We are operating mostly on assumptions and good intentions and hunches.”

Weed and sexual desire – the positive link we all knew was there

Another interesting research has been getting nods among cannabis users, and it’s about a positive link between weed and sexual desire. What many of us knew has now been scientifically proven. Weed does make you feel horny, and sex while high is often better than regular one!

A population-based study, conducted by the Stanford University of School Medicine, has been published in the Journal of Sexual Medicine (JSM). They used self-report questionnaires to gather data of 28,176 women and 22,943 men, all aged between 25 and 45 years old.

The results showed that women who didn’t use cannabis reported that they had sex six times on average in the past four weeks. On the other hand, women who consumed cannabis on a daily basis had sex 7,1 times in the same time frame.

The trend is similar for men. Those who don`t smoke weed had sex 5,6 times in the four-week period, while that figure goes to 6,8 for daily cannabis users.

What these numbers are really telling us is that marijuana users have more sex than those who don`t smoke the plant. And the same behavior goes for all pot users, regardless of their age, sex, race, health, marital or parental status.

Weed and erectile function

A similar study was published in the same journal in February last year. Researchers were trying to find the association between marijuana use among young men and their erectile function.

They conducted a survey among 1265 sexually active young men and found that there is a statistically significant, positive effect of cannabis use on men’s erectile function.

But that’s not all. They also discovered that weed increases men’s sexual desire, orgasmic function, intercourse satisfaction and their satisfaction in general.


Even though our current understanding of how marijuana impacts a man’s fertility potential is far from being conclusive, there seems to be enough evidence to build a pro-marijuana case when it comes to enhanced sexual pleasure.

Knowing that sex is very beneficial for overall health, we can suggest some moderate cannabis smoking before sex, and you can decide for yourself whether it’s making you more relaxed and aroused.

And if you want to get the best experience out of it, check out our list of 13 Strains to Skyrocket Your Arousal that will surely help in your quest for the best sex.


  1. Feiby L Nassan Mariel Arvizu Lidia Mínguez-Alarcón Paige L Williams Jill AttamanJohn Petrozza Russ Hauser Jorge Chavarro: Marijuana smoking and markers of testicular function among men from a fertility centre, 2019, 715–723
  2. A. Suarez-Sarmiento, C. Walker: Association between Habitual Cannabis use in Young Men and IIEF Sexual Domain Scores, The Journal of Sexual Medicine, Volume 15, Issue 2, S67
  3. Sun, Andrew J. et al. Association Between Marijuana Use and Sexual Frequency in the United States: A Population-Based Study, The Journal of Sexual Medicine, Volume 14, Issue 11, 1342 – 1347
About the author
Helena Miles

Experienced journalist with a decade-long experience of researching cannabis. She has been featured in many prominent outlets, such as The Growth Op, National Post and The Province.

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