Marijuana use may lead to higher sperm counts in men, despite past research

  • A study published Wednesday in Human Reproduction suggests that, contrary to prior research, marijuana could potentially increase a person’s sperm count.
  • Researchers analysed health surveys from men who sought fertility treatment at the Massachusetts General Hospital Fertility Center between 2000 and 2017.
  • They looked at each man’s semen volume, sperm count, sperm motility, and hormone concentrations, as well as past and present marijuana use.
  • They found that the men in the study who used marijuana at some point in their lives had higher sperm counts and sperm concentrations than those who never used marijuana.
  • Previous studies, however, have found that marijuana use can lead to lower sperm counts and sperm concentrations.

A study published Wednesday in Human Reproduction suggests that marijuana could potentially increase a person’s sperm count. This finding, which contradicts past research on the topic, shocked the researchers.

“We spent a good two months redoing everything, making sure that there wasn’t any error in the data,” Dr. Jorge Chavarro, lead author of the new study and an associate professor of nutrition and epidemiology, told Time. “We were very, very surprised about this.”

And rightfully so. In 2015, a study published in the American Journal of Epidemiology examined 1,215 healthy young men and found that those who used recreational marijuana more than once per week had lower sperm counts than those who used the substance less often or not at all. In December 2018, INSIDER reported on a small study from Duke University that suggested marijuana use could be linked to lower sperm concentrations, a factor that can affect a man’s fertility.

For this recent study, researchers analysed health surveys from over 650 men who sought fertility treatment at the Massachusetts General Hospital Fertility Center between 2000 and 2017, focusing on each man’s semen volume, sperm count, sperm motility, and hormone concentrations. They also asked the men about past and present marijuana use, though they did not ask about specific dosages or frequency.

Of those surveyed, 55% said they had smoked in the past, while 11% said they currently smoke.


Read more:
Hemp and marijuana come from the same plant, but only one will get you high

The researchers then compared each man’s semen and hormone analysis to his reported marijuana use. They found that the men who currently or previously used marijuana had higher sperm counts and sperm concentrations than those who never used marijuana. The men who had smoked marijuana also had lower levels of follicle-stimulating hormone, which has been associated with a greater risk of infertility, according to the National Institutes of Health (NIH).

Researchers said there is a ‘potential link,’ but not a direct correlation, between marijuana use and sperm count

Although researchers found a potential link between marijuana use and sperm counts, they warned that the findings are not definitive and do “not mean using marijuana is going to increase your sperm count,” Chavarro told Time.

One explanation is that the men in the study who smoked marijuana already had higher sperm counts than those who did not. Another reason, according to the researchers, is that men may be more likely to engage in “risk-seeing activities,” like smoking marijuana, if they have higher testosterone concentrations– something that aids in fertility.

MarijuanaMark Thiessen/APImagesGiven the illegal status of marijuana in some places and its social stigma, the researchers have reason to believe some participants they studied underreported their marijuana use in the surveys.

Additionally, researchers of the current study said the doses of marijuana used by participants may have varied from the doses of participants in past studies, therefore skewing the results. In the previously mentioned 2015 study, the men who used recreational marijuana more than once per week had lower sperm counts and lower sperm concentrations than the men who used marijuana less often. The men in that study who used marijuana at least once per week, in addition to other recreational drugs, had even lower sperm counts, the researchers found.

Given the illegal status of marijuana in some places and its social stigma, the researchers also have reason to believe some of the participants they studied underreported their marijuana use in the surveys.

“[Marijuana use] has potential effects on insurance coverage for infertility services of disclosing this information,” the researchers wrote.

They also noted other limitations of their study. First, participants were only asked about smoking marijuana, not consuming it in other forms, like an edible. Second, because the study’s sampling wasn’t diverse – 88% of the men were Caucasian, 84% were college educated, and the average age was 36.3 years old – the results may not apply to the general population.

With these limitations in mind, it is clear more research must be done to truly understand how marijuana use can affect a person’s sperm and, by extension, their fertility.


Visit

INSIDER’s homepage

for more.

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.