Marijuana Use May Epigenetically Impact Sperm Health

Marijuana Plant Epigenetics

Marijuana has been the topic of much recent debate across the United States, and its legalization has undoubtedly gained some ground. Almost all states in the US have legalized marijuana in some capacity, whether it be for medicinal or recreational purposes which could have a positive effect on both medicine and the economy.

Cannabis has provided some relief for patients suffering from various sicknesses like chronic pain, depression, PTSD, anxiety, and even HIV/AIDs and cancers. As the use of marijuana becomes decreasingly taboo, it is in the interest of public health that we conduct extensive research on all of the effects it may have on a person if it were ever to be completely normalized in our society for every day (legal) use.


Marijuana use does come with some side effects and risks. It can increase heart rate, potentially increase the effects of mental illness, and may impair judgment. However, not much is known about how the use of cannabis can affect the reproductive health of both men and women, or how it can affect the offspring of cannabis-using parents.

According to a recent study out of Duke Health, heavy marijuana use may epigenetically alter a man’s sperm, and could potentially affect the children they conceive. As we know, a father’s exposure to phthalates as well as past trauma, diet, and nicotine use can epigenetically alter his sperm, but it turns out that increased exposure to tetrahydrocannabinol (THC), the active ingredient in marijuana, can cause changes in structure and regulation of the DNA in sperm.

In this study published in Epigenetics, the research team led by Dr. Susan K. Murphy focused their efforts on determining the epigenetic effect that THC may have on the regulation of DNA methylation in two major cellular pathways: Hippo Signaling, and Pathways in Cancer, both of which are crucial to normal human development.

DNA methylation is the epigenetic process of adding a methyl group to the DNA, which results in altered gene expression and often the silencing of a gene. Increased DNA methylation to certain genes is often a characteristic of cancers and other potential health issues, making it an important mechanism to concentrate on.

The team gave a group of sexually mature rats a dose of THC every day for 12 days. The amount of THC they received was equivalent to what a causal human user would experience daily.

These rats were found to have experienced altered methylation patterns in more than 600 different genes, some of them associated with those two pathways, resulting in motility and structural issues for the sperm.

The research team also looked at sperm samples from 24 males: 12 males who were regular marijuana users (the person had smoked marijuana weekly for at least 6 months prior to the study) and 12 who were non-users.

Regular marijuana users not only demonstrated similar methylation patterns to those found in the rats, but they also experienced a significantly lower sperm concentration.

“What we have found is that the effects of cannabis use on males and their reproductive health are not completely null, in that there’s something about cannabis use that affects the genetic profile in sperm,” said Dr. Scott Kollins, a senior author on the study.

Dr. Kollins explained that although they are unsure what this information means regarding reproductive health, it is important to consider these effects as the drug becomes more readily available. If you are considering having a child, the researchers suggest to lay off marijuana usage 6 months prior just to be on the safe side.

Murphy reveals that this study is the first of its kind that exposed the sizeable difference in DNA methylation levels in active marijuana users. With regards to the two pathways that THC effects, Dr. Murphy is unsure how it may affect the offspring of cannabis-using parents, and suggests more research to be done on a much larger scale: “We don’t know whether they are going to be permanent. I would say, as a precaution, stop using cannabis for at least six months before trying to conceive.”


Source: Susan K. Murphy et al. (2018) Cannabinoid exposure and altered DNA methylation in rat and human spermEpigenetics 3:12 1208-1221

Reference: Samiha Khanna “Exposure to Cannabis Alters the Genetic Profile of Sperm” Duke Health News & Media  9 January 2019 Web.

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About Tim Barry 31 Articles
Tim received his B.S in Biology with minors in Chemistry and Business from DeSales University. He has been interested in epigenetics for over a decade and spent three summers researching DNA and Enzymes at Cold Spring Harbor Labs. He is impressed with how the dynamic nature of epigenetics can continually affect someone’s lifestyle and their future descendants. During his down time, Tim will be at the beach, playing golf, at the gym, or with his friends enjoying a fine glass of rye whiskey.


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