How Does Cannabis Affect Testosterone Levels?

Data from recent studies is promising.


It’s possible that your physician may have told you a pretty sobering fact — globally, sperm counts have gone down by as much as 50% in men, and one in eight couples in America are dealing with infertility issues. Because of that and a declining birth rate, physicians and researchers have been casting around for all sorts of culprits, from the phthalates behind the “new car smell” to radiation from cellular stations and laptop computers. And of course, they’ve also decided to ask questions about cannabis on top of it as well, too. Even though cannabis is a known aphrodisiac, there have been plenty of rumblings about whether or not cannabis is partly to blame for lowered sperm counts. There’s even a health supplement marketed to men that claims to compensate for their supposedly compromised virility.

Given the variety of scary rumors and moral panics that have historically surrounded cannabis, however, one has to ask: Is cannabis REALLY to blame for male infertility? Well, from what’s been discovered, the jury is still out, with far too many conflicting reports, both encouraging and discouraging, to tell for certain. But if it’s one thing that can be said, there’s no shortage of potential culprits for this phenomenon, with nothing definitive fingering cannabis as of yet.

The Good News

Over the past few years, there have been a few well-publicized studies that suggest moderate cannabis use may actually increase sperm count in adult males. A 2019 study conducted at the Massachusetts General Hospital fertility center collected 1,143 semen samples from 662 men over the course of 17 years. Over half of them, when asked about their drug use, had acknowledged smoking cannabis at one point in their life, with 11% being current users. To their surprise, they found the sperm concentration was significantly higher for the cannabis users — 62.7 million sperm/mL – than it was for the non-users (45.4 million sperm/mL), with no significant differences seen between current and former users. Total sperm count was also higher for the users as well. A similar Canadian study found that males at an andrology clinic not only had higher scores on a sexual health clinical inventory and higher total testosterone, they also had higher sexual frequency than non-users as well.

In addition, a 2020 study on past-year cannabis use conducted by researchers at Johns Hopkins University, the University of Miami and the University of Chicago turned its focus to testosterone. Analyzing data from the National Health and Nutrition Examination Survey, they looked into the testosterone levels of over 3000 men aged 18 and over who had reported using cannabis at least once in their lives. They found those who had used cannabis in the past year had higher testosterone levels than those who hadn’t, particularly those who had used at least two or three times a month. While the testosterone increases are small, and declined as their use increased, their elevated levels still held against non-users. Since testosterone is crucial in order to create healthy sperm, this discovery is good news indeed.

Bearing Mind

Naysayers will however point to more recent studies, particularly in animals, that show altered reproductive functions and hormonal imbalances. One particularly alarmist paper out of the Oregon Health & Science University looked into adult primates who were fed cannabis edibles and associated their usage with “decreased levels of testosterone and severe testicular shrinkage.” One Brazilian study which studied male patients at an infertility clinic noted that sperm count and testosterone levels were not influenced by their cannabis use, but shifts in hormones like estradiol (an estrogen) and prolactin, which can stimulate lactation in mothers, were.

In both the positive and negative studies, mechanisms for either elevated sperm counts in humans from Boston or decreased testosterone levels for primates in Oregon have not been determined. However, it’s clear that there’s more going on in the body than we can adequately measure for. And even doctors, confronted with better-informed patients, have to acknowledge this. “It is not going to work to use scare tactics to create fear among adolescent and young male patients, friends, and family who are using or considering smoking cannabis,” says Sherry Yafai, MD on the testosterone findings. “Lecturing the young male generation will only identify you as being out of touch with the latest research.”