New Study Warns Delta-9-THC and CBD Alters Sperm Function

At some point, most cannabis users have likely heard that weed negatively impacts male fertility. However, this idea has largely been regarded as an “old wives’ tale.” Cannabis is growing in popularity as a recreational substance since it has become more widely legalized across the US. With more adults of reproductive age looking to cannabis over alcohol as a way to decompress, the impact of cannabis on fertility is becoming less of a laughing matter. A new study published in the journal Human Reproduction warns that cannabis fertility issues should be taken seriously.

To understand the implications of this cannabis fertility study, you need to know a little bit about how sperm work. In order for sperm to fertilize an egg, they need to activate a type of “swimming” motion called “hyperactivation [1].” Hyperactivation is triggered by an influx of calcium that passes through a molecular channel called “CatSper.” This activation process is regulated by a number of compounds inside the cell, including endocannabinoids. If sperm cannot hyperactivate, they won’t be able to reach the egg and penetrate it within the small twelve-hour lifespan of the egg.

Here’s an extremely simplified overview of the process [1]:

1. Compounds in the sperm cell signal that it is time to hyperactivate
2. Calcium rushes through the CatSper channel on the sperm’s tail
3. The tail hyperactivates and starts “swimming”

The University of Geneva’s Department of Genetic Medicine and Development partnered with Hospital of Valais’ Service of Clinical Chemistry & Toxicology to study the effects of delta-9-tetrahydrocannabinol (delta-9-THC) and cannabidiol (CBD) on the sperm of male volunteers [2]. Researchers found the first direct evidence that THC and CBD are prime culprits behind cannabis fertility issues. Their study observed that THC and CBD both inhibited the influx of calcium through CatSper channels.

While many have suspected that THC impairs sperm, it might surprise many that CBD is also to blame for cannabis fertility issues. The research team notes that compared to CBD, THC appears to have further inhibitory interactions with the compounds that signal hyperactivation conditions [2]. With these new findings, fertility doctors and couples experiencing fertility difficulties can be better informed about the pitfalls of cannabis and male fertility. In addition to discontinuing marijuana use, CBD supplements should also be avoided when seeking to get pregnant.

References

1. Lishko, P. V., & Mannowetz, N. (2018). CatSper: A Unique Calcium Channel of the Sperm Flagellum. Current opinion in physiology, 2, 109–113. https://doi.org/10.1016/j.cophys.2018.02.004