How Cannabis Affects Male Fertility
4 min

How Cannabis Affects Male Fertility

4 min
Growing Seedshop

The chance at creating life is an opportunity not all have. Some research would have you believe that cannabis can decrease fertility. However, a more specific analysis shows promise of the opposite.

These days, everywhere you look you see scaremongering about cannabis. According to these sources, lack of motivation, poorer health and infertility are all part of the hit list for regular users of weed. Despite this negative stereotype, numerous research papers continue to be released showing beneficial uses and health enhancing effects that the cannabinoids within cannabis can have on the human body. Let's look at one of the most alarming aspects of health cannabis is fabled to effect: fertility, or more a lack it. Poor fertility can dash the hopes of many a man or women trying to conceive, so it is rather alarming to see research that suggests a link between the regular smoking of marijuana and a decrease in sperm count among young men. Yet, is all as it seems? We are not so sure.


Now, never one to laugh in the face of science, a paper published in the American Journal of Epidemiology has presented some interesting findings – findings that would suggest that yes, cannabis does lower sperm count.

The study took a sample of 1,215 Danish males between 18-28 years over the period of 2008 to 2012. Data was collected from a compulsory medical examination men go through to determine fitness for military service. The procedure consisted of providing a semen and blood sample as well as a physical examination. As part of the examination, they were asked a series of lifestyle questions about the use of recreational drugs in the last three months, with 45% of participants admitted to smoking marijuana. It was found that those who smoked regularly (once a week) displayed a 29% reduction in sperm count. Users who had reported other recreational drug user alongside cannabis had their sperm count reduced by 55% and sperm concentration by 52%. The paper later goes on to discuss the link between tobacco and decreased fertility. Factoring that in, the Danish researchers still claimed a link between weed and lower sperm levels.


Firstly, the problem faced by research such as this is the uncontrollable factors that cannot be considered or taken into account. In this case, the questions posed simply asks about their consumption of cannabis in the general sense. Cannabis, as we know, is a complex organic matter made up of a series of cannabinoids that all affect the body and mind in different ways - dependent on the concentration and ratios of each cannabinoid. By assuming the general label of marijuana, the research is no closer to determining what “within” weed may be causing this lowered sperm count. Strains can have huge variations in their genetic makeup based on the effect the user wishes to experience. However, this is a factor that the vast majority of cannabis research, both negative and positive, fail to take into account. There are very few that have actually looked at the differences between the types of cannabis.

The sample size is also a factor when looking at the validity of the results produced. Giving the variation in hormone production from person to person and the direct impact this can have on semen levels; diet, exercise, and genetic heritage can all play a part in the respective levels. Not only this but at different stages in our life these levels can also vary. A significantly larger sample size is required, taking males from different nationalities and/or areas of the same country. This would allow a broader and more diverse sample size to be used when trying to establish if weed specifically is having an impact on male fertility. Alongside this the researchers also state that;

“We cannot exclude the possibility that the men who used marijuana generally have an unhealthier lifestyle and health behaviour, which may also affect their semen quality and hormone levels.”

This statement points out one of the biggest flaws with the research, and many like it. All it does is establish correlation, not causation. It is impossible to say from a survey whether cannabis really is the cause. It could just be the case that Danish men who smoke cannabis on a regular basis also get very little exercise or eat poorly. It is hard to make generalisations with this kind of evidence – concrete causation is needed. This is not to say the research is invalid; it certainly gives us a good insight into a potential link, but it needs to be investigated much more deeply.


Now that we understand some of the limitations faced by research such as this, what do the results show when things get more specific? A new study published in the FASEB Journal looked at how CB2 receptors could be stimulated to help produce sperm, not limit or reduce it as previously thought.

This development centres around the cannabinoids receptors all over our body. Forming part of the endocannabinoid system they can be found in pretty much every cell of the body. They tend to be stimulated by CBD and CBN rather than the psychoactive component THC.

While the research doesn't claim cannabis is necessarily good for fertility it shows that cannabinoid receptors can play a part in male fertility and that the right application and concentration of cannabinoids is crucial to understanding. The research involved using three different groups of mice. The first group was administered with a specific activator for the CB2 receptor, (JWH-133), while the second group was given an inhibitor of the same receptor and the third group a saline solution. The first group given the CB2 activator showed an acceleration in a process called “Spermatogenesis”. This process is when germ cells develop into sperm cells, something that can take in humans over two months.

It is worth noting that this is still a research topic in its infancy, but it could pave the way for a different mindset with regards to the consumption of cannabis. As more and more research is published looking at the impact of cannabinoids on our bodies, we can hope to better understand cannabis and how it can be implemented in improving quality of life. It is all too easy to assume that cannabis is a harmful drug when it is the stance often taken by governments and media; negativity breeds negativity, but by shifting the focus on research we can start to improve people's lives. What better way to improve it than by giving people a chance at creating life?



Written by: Lucas
Lucas is a part-time writer and full-time visionary. An anonymous psychonaut blending into society with his suit and tie, he works to bring evidence-based rationality to the masses.

      Find out about our writers  

Read more about
Growing Seedshop
Search in categories