Smoking cannabis may increase sperm count

Smoking cannabis may increase sperm count

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By Ananya Mandal, MDFeb 7 2019Reviewed by Kate Anderton, B.Sc.

A new study has found that men who have smoked cannabis at some point in their lives have higher sperm counts than men who have never smoked the drug. The findings were published in the latest issue of the journal Human Reproduction.

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The study, which was conducted by researchers at Harvard University, looked at 1,143 semen samples of 662 men who were registered at different fertility clinics between 2000 and 2017. These men were asked about their cannabis habits and previous drug-taking behavior.

The researchers noted that around half of the men enrolled in the study had previously tried or had currently used cannabis.

After examining the samples, the researchers found that only around 5 percent of the men who had smoked cannabis before had clinically low sperm counts, compared to 12 percent of the men who had never tried cannabis before.

They noted that the average age of the men at the time of sample collection was 36 years and of these participants, 55 percent had used marijuana at some point in their lives.

According to the authors of the study, the reason behind this could be the effects of cannabis on the endocannabinoid system of the body. This system sends signals to the brain and these signals may play a role in fertility, they explain.

The scientists also noted that the men who had tried or were using cannabis had a higher level of the male hormone testosterone. This could also be responsible for their higher sperm count.

An equally plausible interpretation is that our findings could reflect the fact that men with higher testosterone levels are more likely to engage in risk-seeking behaviours, including smoking marijuana.”

Dr. Feiby Nassan, Study Author

Dr. Jorge Chavarro, Associate Professor of Nutrition and Epidemiology at the Harvard T. H. Chan School, warned that this study only showed that little knowledge we have about marijuana and its effects on reproductive health and fertility.

In a statement, Chavarro said that the results cannot be taken on face value and need to be “interpreted with caution”.

There have been numerous studies in the past showing that cannabis worsens sperm quality and reduces fertility among men. Hence, Nassan and team did not expect to see an increase in sperm count, and this was entirely contrary to their hypothesis. She also warned that the participants could have under-reported their use of cannabis.