THC Could Have Potentially Harmful Effects for Men

Legalizing marijuana in many states across the US has led to more access for scientific study. But marijuana users should steel themselves in case of unfavorable results.

A new study by Duke University Medical Center indicates that THC, the high-inducing compound in marijuana, might have negative effects on men’s sperm.

According to a Duke Health press release, the compound appears to affect something called epigenetics (1).

Epigenetics involves genetic changes in the way those genes express themselves, rather than changes to the DNA sequence. At times, those changes can be transferred to future offspring.

The Duke study involved 24 participants, including THC-users and non-users. According to the press release, THC appears to affect two major cellular pathways and alters the DNA’s normal development.

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The research is unclear whether those changes are transferred to children, the press release says. However, researchers are showing concern over the level of access men have to this potentially harmful compound. They are recommending caution until further research can make a final conclusion.

The study’s paper details that their findings are consistent in rat experiments as well (2). Hundreds of different genes were affected in both rat and human groups.

In addition, the paper cites a previous study’s findings: mice born to parents who had been exposed to THC showed a greater chance of “self-administering heroin as adults.” This effect raises questions about the influence THC may have on human children.

What’s more, the researchers found the genetic changes compounded the more THC that participants used. In humans, the researchers confirmed that cannabis users hold lower sperm counts than non-users, the paper says.

Duke researchers do have plans to continue their studies, according to their statement. The current study provides insight into the matter but cannot make definitive statements due to its study size.

In addition, the amounts of THC varied widely among participants who used cannabis. Users also consumed alcohol at a slightly higher rate than non-users, though not clinically significant.

Researchers hope to find out whether these genetic changes can be reversed and how they may affect children in future studies. The study was published online in Epigenetics this month.


  1. Duke University Medical Center. (2018, December 19). Exposure to cannabis alters the genetic profile of sperm: Whether genetic changes can be reversed or are passed on to children is still unknown. ScienceDaily. Retrieved December 26, 2018 from
  2. Murphy, S. K., Itchon-Ramos, N., Visco, Z., Huang, Z., Grenier, C., Schrott, R.,…Kollins, S. H. (2018). Cannabinoid exposure and altered DNA methylation in rat and human sperm. Epigenetics. doi: 10.1080/15592294.2018.1554521.