Medically Reviewed by
Jason Crawford

Article Last Updated on January 8, 2023

As the popularity of marijuana and marijuana-derived products is increasing, so does research on its health benefits and side effects. Legalization has opened a brand new trajectory towards weed for both experienced users and rookies.

Science has resolved a lot of questions regarding the cannabis plant, but a lot of them still remain unanswered. One of them is about the relationship between marijuana use and fertility. Over the decades, there has been a fair amount of research on this topic, but there hasn’t been one official consensus. Therefore, the use of weed and its effects on fertility are still being studied.

In the following article, we’ll discuss the effects that smoking weed may have on male and female fertility and try to get some perspective on this question.

Infertility in Men and Women

Fertility problems are not uncommon among couples and both men and women are equally likely to suffer from them. Infertility means that active attempts at conceiving for longer than six months have been unsuccessful. When couples face these issues, they often see fertility specialists in order to undergo fertility treatments, like in vitro fertilization (IVF).

Briefly, male infertility most often manifests as decreased sperm health, like having low sperm count and low sperm motility (the ability of sperm to move and swim), or unusually shaped sperm. These changes can result from various medical conditions and/or ejaculation disorders.

Female infertility manifests as ovulation disorders or problems in the uterus and fallopian tubes which can affect the menstrual cycle, mostly caused by a variety of medical conditions, like polycystic ovary syndrome (PCOS), hormonal imbalances, endometriosis, and others.

The Effects of THC on the Body

As you may have already known, the human body has its own endocannabinoid system which is a biological system composed of neurotransmitters called endocannabinoids. These endocannabinoids attach to different cannabinoid receptors located in the nervous system.

The endocannabinoid system is responsible for maintaining homeostasis in the body. It’s involved in many processes, like hunger, memory, immune response, communication between cells, sleep, and even reproduction (Dunne, 2019).

Now, the cannabinoids in marijuana, THC (tetrahydrocannabinol) in particular (the psychoactive ingredient that gets you high), also attach to these cannabinoid receptors and affect many bodily functions.

Science on Marijuana Use and Human Reproduction

While various studies on marijuana and its health benefits have been carried out, compared to other conditions, its effect on human reproduction is more or less understudied. There have been some old and new studies, animal trials as well as human trials, but few of them were on a larger scale, and some of them are conflicting.

Let’s look at what has been found so far regarding male and female fertility, and smoking weed.

Female Fertility

Speaking of how weed interacts with the body’s endocannabinoid system, a 2016 report published in the Yale Journal of Biology and Medicine that focuses on marijuana and female fertility explains that weed may negatively impact the ovulation cycle, leading to reduced fertility.

The endocannabinoid system plays a role in the process that produces mature eggs from ovarian follicles because there are endocannabinoid receptors located in follicle cells. So, when these receptors are impacted by the cannabinoids in weed, the report states, they seem to get mixed up and work differently, causing dysregulation in the flow of the normal reproductive function.

Similarly, a recently published animal study in the Journal of the Endocrine Society suggests that THC can negatively impact female eggs by impairing their ability to produce viable embryos. It implies that the development of the embryos will be poor, making them unable to last past the first week of development, and eventually leading to decreased fertility over time.

On the other hand, a 2018 clinical trial that involved 758 male and 1076 female participants who were smoking weed while actively trying to conceive, has deduced that neither smoking weed nor frequency of marijuana use had any impact on fertility for both men and women, even though the hypothesis was different.

Male Fertility

When it comes to cannabis use and male fertility, there have been more animal-based studies than human trials, and many of them have demonstrated that smoking weed has a negative impact on the male reproductive system.

One human trial was conducted in a 2015 clinical study with 1215 young men between the ages of 18-28 of which 45% had been smoking marijuana for 3 months prior to the study. The researchers found that regular marijuana users had lower sperm concentration and sperm motility, and a lower sperm count by 29%. Overall, their semen quality was poor, and it was even worse for participants who were taking other recreational drugs combined – their sperm concentration was reduced by 52%.

To add to the discrepancy, a different study published in the journal Human Reproduction contradicts this by claiming that regular users who smoke marijuana had higher sperm counts compared to men who had never used weed. Similarly, another study suggests that marijuana use was strongly associated with an increased testosterone concentration.

So, Should You Avoid Weed if You’re Trying to Conceive?

It’s obvious that the relationship between the effects of marijuana and fertility is complicated because of the conflicting scientific findings. It could be said that marijuana use can have the biggest impact on people with pre-existing fertility issues, but given the inconclusive evidence, it would be wrong to take anything at face value.

Some people who use marijuana do not have any problems with fertility, so you can see that in some cases it’s highly individual the way one’s reproductive system would react to the use of marijuana.

Given that starting a family is a very big step in anyone’s life, we would say that playing it safe would be the better option. Quitting smoking weed may be difficult or easy depending on how frequently you’ve been using it, but it’s the safer option nonetheless.

If you have both been regular marijuana smokers, then quitting will definitely lower the risk of negative health effects leading to infertility. Needless to say, it’s also recommended that both the female and the male partners quit, instead of just one.

There is still a lot left to explore and understand regarding marijuana use and reproductive health. There is a lot of room left for clinical trials to be conducted before we have any certain answer to this question, so for now, we can only say that you’ll probably have more chances to conceive if you lay off the joint for a little while.

Additional Sources

Caitlin Dunne, P., & Caitlin Dunne, P. (2020). The effects of cannabis on female and male reproduction | British Columbia Medical Journal. Retrieved 30 October 2020, from https://bcmj.org/articles/effects-cannabis-female-and-male-reproduction 

Walker, O.S., Holloway, A.C. & Raha, S. The role of the endocannabinoid system in female reproductive tissues. J Ovarian Res 12, 3 (2019). https://doi.org/10.1186/s13048-018-0478-9

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


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