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Marijuana Use Linked to Higher Sperm Count

It was once thought that men that used marijuana would also have a lower sperm count. Studies were even conducted to back up the belief. Now however, the latest study conducted in Massachusetts has blown that theory out of the water. More while more research needs to be done. This current study though, provide good news for men that enjoy cannabis use, and are worried about their fertility and reproductive health.

New Study

The new study that sheds light on how marijuana can affect a man’s sperm count is titled “Marijuana smoking and markers of testicular function among men from a fertility center.” It was published in the February 6, 2019, issue of the scientific journal, Human Reproduction 

In the study, 662 men were observed. Some said they had never used cannabis. Others were regular users, and some used it, but only occasionally. The study took place over a seven-year period from 2000 to 2017. It was conducted at the Massachusetts General Hospital Fertility Center. The men provided sperm and blood samples, and answered questions about their marijuana use.  
Image of sperm count
Most men in the study, 55 percent, had used the drug at some point in their life. However, they weren’t active users. A smaller portion, 11 percent of the men, stated that they currently used the drug regularly. 

The men that stated they had used cannabis showed an average sperm count of 63 million sperm per milliliter of semen. Those who had never used cannabis had just 45 million sperm per milliliter. Researchers also took into consideration other factors that could affect sperm count. These included alcohol use, age, and whether or not the participants smoked cigarettes.

The study also found that five percent of marijuana users had lower sperm counts than average. However, 12 percent of those that never used the drug had lower than average sperm counts.  

The data collected seems to show that cannabis use may lead to higher sperm counts in men. But, the study also states that others factors may be at play.  

Researchers took into consideration that men with higher sperm counts would also have higher testosterone levels. They suggested it may be these elevated levels, and not cannabis use, that leads them to engage in riskier behaviors, such as drug use.

For the time being, researchers involved in the study did say that the endocannabinoid system is affected by cannabis. They concluded that lower levels of marijuana could increase a man’s sperm levels. Those that use it more often may have the opposite effect.

Perhaps it’s this reason that this study contradicts so many studies that have been done in the past.

Previous Studies 

Just four years ago, a study in the American Journal of Epidemiology studied twice as many men than this most recent study. In that study 1,215 men were studied to decipher what effect cannabis had on sperm count. It was found that men that used marijuana more than once a week had lower sperm counts than those that didn’t use the drug at all.

A study done at Duke University in December of 2018 backed up those findings. That study also found that cannabis use can negatively affect a man’s fertility.  

Researchers in Massachusetts expected to conclude the same findings, and were surprised when they didn’t.  

“Our findings were contrary to what we hypothesized at the start of the study,” said Feiby Nassan, a postdoctoral research fellow at the Harvard T.H. Chan School of Public Health, and the lead author in the study.  

Scepticism Remains 

With so many studies presenting conflicting ideas on men’s fertility and marijuana use, it’s clear more research needs to be done. In this most recent study, researchers also noted that erasing the stigma may encourage men to come forward about their cannabis use.

In its conclusion the study said, “The most important limitation of the study is the possibility of under reporting of marijuana use given its status as an illegal drug during most the study, its social stigma and potential effects on insurance coverage for infertility services of disclosing this information.”

In addition to this limitation, the study had others as well. One of those was that the study did not take into consideration the entire general population. Instead it focused on men that were predominantly white, had a college education, and were an average age of 36. All participants were also already seeking fertility treatment before the study began.

Cannabis use increases sperm countThe researchers involved in the study also admitted that more work had to be done on the subject before results can be considered conclusive. 

U.S. lead researcher, Dr. Jorge Chavarro, from the Harvard T.H. Chan School of Public Health stated, “These unexpected findings highlight how little we know about the reproductive health effects of marijuana, and in fact of the health effects of marijuana in general.”


So, does marijuana have a positive or negative effect on a man’s sperm count and reproductive health? The jury is still out on that one. However, what may still hold true is that cannabis may not have the negative impact it was once thought to. Increasing legalisation, and reducing the stigma may allow researchers to finally come to stronger conclusion.



MSNL Team MSNL Team / 25th February 2019

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