Stopping THC Consumption Can Reverse Male Fertility Outcomes

In 2022, Oregon Health & Science University (OHSU) researchers revealed that persistent cannabis consumption could significantly affect male fertility and reproductive outcomes in nonhuman primates. However, it was not established if these consequences were irreversible. Now, a new study conducted by the same team and published in Fertility & Sterility confirms that cessation of THC usage can alleviate these detrimental effects.

Delta-9-tetrahydrocannabinol (THC), the primary psychoactive constituent in cannabis, is prevalently used by men of reproductive age worldwide. Many users remain unaware of its potential adverse effects on reproductive health, primarily because of a scarcity of safety data. This study delves into the reversibility of these impacts.

“It’s so important that we research, understand, and educate about the implications of THC on reproductive health, especially as use continues to increase among individuals of reproductive age and more states legalize cannabis,” said the study’s corresponding author Jamie Lo, M.D., M.C.R., associate professor of obstetrics and gynecology, OHSU School of Medicine, and Division of Reproductive & Developmental Sciences at the Oregon National Primate Research Center (ONPRC).

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Utilizing a nonhuman primate model, researchers examined the impact of THC by administering progressive doses over roughly seven months. They specifically assessed changes in the male primates' reproductive organs, testes tissue, and sperm quantity and quality. The study found that THC exposure led to a marked reduction in testes size and negatively affected male reproductive hormones, which can adversely impact overall fertility. Furthermore, THC exposure influences sperm by altering the regulation of genes crucial for nervous system development, including those associated with autism spectrum disorder.

After stopping THC exposure for around four months, researchers found that these detrimental effects were partially reversible, implying that damage from persistent THC use can be partly remedied.

Although more research is necessary to fully comprehend the biological mechanisms behind this reversal process, this study provides an initial comprehensive understanding of the benefits of stopping THC use during family planning. It also offers insights into the minimum duration of abstinence from THC required to repair damage after long-term use. Practitioners can use the results of this study to effectively counsel patients on THC-related risks and recommendations before attempting conception.

“We understand that for teens and young adults, family planning might not be top of mind,” said Jason C. Hedges, M.D., Ph.D., associate professor of urology in the OHSU School of Medicine, Division of Reproductive & Developmental Sciences at ONPRC. “However, THC, even in moderate doses, could impact their fertility outcomes, so this is a serious concern for us as healthcare providers. The more we can understand and define this issue, the better information we can provide patients to optimize their reproductive health.”