Researchers at the Harvard T.H. Chan School of Public Health released a study on Tuesday which revealed that men who have smoked marijuana at some point in their life have significantly higher concentrations of sperm, and were loaded with higher serum testosterone levels compared to men who have never smoked marijuana.
“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,” Jorge Chavarro, Associate Professor of Nutrition and Epidemiology said in a statement. “Our results need to be interpreted with caution and they highlight the need to further study the health effects of marijuana use.”
Massachusetts General Hospital Fertility Center also came to the conclusion that the commonly held phallic fallacy that smoking marijuana might exacerbate semen quality is ultimately a bust, giving the shaft to past studies, which suggested negative effects on male reproductive health. Experts said the majority of those studies focused on animal models or on men with histories of drug abuse.
Between 2000 to 2017, scientists collected 1,143 semen samples from 662 mostly college-educated white men. Among the participants, 55 percent reported having smoked about two joints at some point. Of those, 44 percent said they were past marijuana smokers and 11 percent classified themselves as current smokers.
“Our findings were contrary to what we initially hypothesized. However, they are consistent with two different interpretations, the first being that low levels of marijuana use could benefit sperm production because of its effect on the endocannabinoid system, which is known to play a role in fertility, but those benefits are lost with higher levels of marijuana consumption,” Feiby Nassan, lead author of the study and a postdoctoral research fellow at Harvard Chan School said in a press release. “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 behaviors, including smoking marijuana.”
The study was published in Human Reproduction.