Does weed impair male fertility?

Scientists have found no significant link between marijuana use and reduced sperm quality in men. 

According to the World Health Organization (WHO), a healthy sperm count is 15 million sperm per millilitre (ml) of semen or more. Anything below this threshold is considered low.

The new findings from a peer-reviewed study published last week in the Journal of Andrology by researchers from the Boston University School of Public Health analysed semen samples from 921 men. Of the participants, 22.6 per cent reported being regular cannabis users, and 3.3 per cent said they used it daily.

Also read: Causes and risk factors for male infertility

“Despite varying levels of cannabis use among the participants, we found no significant difference in sperm concentration, motility, or morphology when compared to non-users,” the researchers noted.

Although variations in sperm parameters were observed, they did not reach a level of statistical significance, suggesting that cannabis use, at least at the levels reported in the study, may not impair male fertility.

In Kenya, while the Narcotic Drugs and Psychotropic Substances (Control) Act, 2022 allows cannabis for medical and scientific purposes, recreational and commercial use remains illegal.

"Chronic cannabis use among human males has been associated with lower testosterone concentrations and alterations in other hormones relevant to semen quality,” the researchers observed while breaking down their findings, also noting that past studies have also shown associations of chronic cannabis use with poor semen quality, but results have been inconsistent across different hormonal and reproductive measures.

“In this sample, at least there was no pattern found. It doesn't settle the issue one way or the other, but it is another useful piece of evidence for scientists looking into the potential associated with cannabis,” the scientists stated.   

Also read: Doc, I have no sperm. What now?

"Further control for potential confounders, including body mass index, had little influence on the study results, and results were similar among non-smokers of tobacco.” 

While he agreed with the findings of the study, Dr Rajesh Chaudhary, the lead in-vitro fertilisation specialist at Fertility Point, pointed out that sometimes problems with sperm count and quality are associated with hormonal imbalance such as hypogonadism (reduced hormone production), a genetic problem such as klinifelter syndrome.

Klinifelter syndrome is a condition where men are born with an extra X chromosome, having had undescended testicles as a baby, a structural problem, previous surgery to the testicles or hernia repairs.

Klinifelter also manifests itself when testicles become overheated, or when men sink in excessive alcohol consumption, smoking, using drugs such as marijuana, cocaine or miraa and medications including testosterone replacement therapy, long-term anabolic steroid use, cancer medications including chemotherapy, some antibiotics and antidepressants, as well as being overweight or obese.

The expert added that there is a possibility of low sperm count being a hereditary issue, but the cases are very few.

“It is advisable to do a genetic test as well as a microdeletion test that provides information about the health of your still-developing baby,” he said.

Dr Chaudhary also told Nation that the quality of sex does not in any way affect the quality of sperm, and having a low sperm count can make it more difficult to conceive naturally, though successful pregnancies can still occur.

He said about one-third of infertility cases diagnosed today are due to male factors, and in Kenya, sperm morphology, motility and volumes have all been on the decline.

Dr Chaudhary explained that when men hit 45 years of age, their sperm quality declines because of DNA fragmentation, but that is now evident in young men.

World Bank data shows that Kenya’s fertility rates have declined from 7.3 children per woman in 1960 to 5.1 in 2000. In 2020, it fell to 3.3 children per woman.

But according to Dr Joachim Osur, a sexologist based in Nairobi, scientists must now go beyond cannabis.

“I think we need to think beyond just sperm to the overall effects of cannabis on sexual function and social wellbeing. Used for recreation, the risk of dependence on the drug and disruption in relationships can be massive. 

“When relationships are disrupted, multiple sexual dysfunctions such as erection failure happen,” he told Nation while urging researchers to be more comprehensive on the matter. 

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