As more and more states legalize marijuana, there has been a corresponding increase in its utilization. In fact, it’s been estimated that 16.5% of adults in the US regularly use marijuana. Understandably, this has led to increased interest in possible health benefits and risks, including its potential effects on male fertility.

There is evidence that the active ingredient in marijuana, tetrahydrocannabinol (THC), interacts with organs involved in the production of sperm. For example, THC interacts with receptors on the pituitary gland, which is involved in testosterone synthesis, a necessary hormone for sperm production.

Overall, high quality studies in humans are lacking, and existing evidence is somewhat mixed. In fact, one study found that sperm concentrations were increased in men who had previously smoked marijuana at some point in their lives. Additionally, some studies have found an association with higher testosterone levels and marijuana use.. That being said, these studies are not without their flaws, and the majority of existing evidence suggests that marijuana use negatively affects semen parameters, particularly frequent use.

“Typically, I do discuss with my patients that the evidence is somewhat mixed, but I usually recommend guys at least cut back on their marijuana consumption if not stop completely,” says Dr. Luke Machen.