Marijuana Intake Linked To Improve Sperm Counts In Surprising Study
The use of some substances, including marijuana and cocaine, may reduce sperm counts. Men who smoke cigarettes may have lower sperm counts than men who do not smoke according to previous health research. But of recently, new study prove men who smoke marijuana could have higher sperm counts.
Men who smoke marijuana have significantly higher sperm counts than men who never touched the drug, according to a study published Feb. 6 in the journal Human Reproduction. The study looked at men who were seeking help at a fertility clinic, not the general population.
The findings are “not consistent” with previous research, which has suggested that marijuana has a harmful effect on men’s testicular function, the researchers said.
However, the study doesn’t mean men should start smoking pot to up their sperm counts. The findings are far from conclusive, and more research is needed to understand whether smoking marijuana could indeed, at certain levels, have a positive effect on sperm production.
Related: Pot Smoking May Lower Sperm Count
But the study does highlight how little researchers know about the effects of marijuana on reproductive health, study senior author Dr. Jorge Chavarro, an associate professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health in Boston, said in a statement. “We know a lot less than we think we know.”
Marijuana and sperm
The study was not a large one, and was done on men seeking fertility treatments. Harvard scientists checked 662 subfertile men who came to the Massachusetts General Hospital Fertility Center between 2000 and 2017. Their cannabis use was self-reported.
The men answered survey questions about how often they smoked marijuana or used other drugs, and they also provided sperm and blood samples. Of the subjects, they found that 365 men who had previously smoked cannabis in moderate amounts had significantly higher sperm concentration than the 297 men who had never smoked. Note that the scientists adjusted for factors known to affect sperm production, including age, abstinence time, smoking, and intake of coffee, alcohol and cocaine.
The researchers found that men who reported ever having smoked marijuana had an average sperm concentration of 63 million sperm per milliliter of semen, compared with 45 million sperm per milliliter of semen among those who had never used marijuana. The findings held even after the researchers took into account some factors that could have affected sperm concentration, such as age, cigarette smoking and alcohol use.
What’s more, only 5 percent of the marijuana smokers had lower-than-normal sperm concentrations — that is, lower than 15 million sperm per milliliter of semen. Among men who never smoked marijuana, 12 percent had lower-than-normal sperm concentrations.
Among men who had ever smoked marijuana, those who used it more often had higher testosterone levels than those who used it less often.
“Our findings were contrary to what we hypothesized at the start of the study,” study lead author Feiby Nassan, a postdoctoral research fellow at the Harvard T.H. Chan School of Public Health, said in the statement.
But the study can be interpreted in several ways. It may be that low or moderate levels of marijuana use have a beneficial effect on sperm production, but heavier use reverses this effect. Or, it could also be that men with higher testosterone levels are more likely to engage in “risky” behaviors such as drug use; and the researchers found the link between marijuana and sperm count “because men with higher testosterone, within normal levels, have higher sperm counts and are more likely to smoke cannabis.”
It’s known that moderate- to heavy-use of tobacco or alcohol is tied to lower sperm counts, but whether marijuana has the same effect is up for debate, said Dr. Sarah Vij, a urologist at the Cleveland Clinic who was not involved with the study.
And yet, the study still found that men who said they used marijuana at least a year ago had higher sperm counts than men who used it more recently.
The researchers also noted that their study was conducted among men who visited a fertility clinic, and so the results may not necessarily apply to the general population. In addition, men in the study self-reported their marijuana use, and it’s possible that some participants were not truthful about their marijuana use, due to the social stigma or illegal status of the drug in Massachusetts at the time the data was collected.