Addiction Drug Use Marijuana Research Shows Marijuana Smokers Have Lower Total Sperm Counts By Buddy T Buddy T Facebook Twitter Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism. Learn about our editorial process Updated on October 09, 2020 Medically reviewed Verywell Mind articles are reviewed by board-certified physicians and mental healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Steven Gans, MD Medically reviewed by Steven Gans, MD Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital. Learn about our Medical Review Board Print Diverse Images / UIG / Getty Images The prevalence of marijuana use among males of reproductive age has never been higher, while male factor infertility is also on the increase. Researchers believe that the spread of legal medical and recreational marijuana use in the U.S. may be a contributing factor in the increase in male infertility. The Link Between Marijuana Usage and Male Infertility Marijuana contains the cannabinoid drug THC (tetrahydrocannabinol), its primary psychoactive chemical, as well as other cannabinoids. Several studies have linked marijuana usage and male infertility but how the use of the drug affects infertility has been attributed to a variety of reasons. One study found that men who smoke marijuana frequently have significantly less seminal fluid, a lower total sperm count and their sperm behave abnormally. All of these factors could adversely affect fertility. The University at Buffalo study was the first to exam marijuana's effects on the specific swimming behavior of sperm from marijuana smokers and to compare the results with sperm from men with confirmed fertility. While researchers are still unsure of the exact reasons for these effects, the results of studies clearly reveal that the active ingredients found in marijuana impact sperm and negatively impact fertility, according to Lani J. Burkman, PhD, lead author on the study. "We don't know exactly what is happening to change sperm functioning," said Burkman, "but we think it is one of two things: THC may be causing the improper timing of sperm function by direct stimulation, or it may be bypassing natural inhibition mechanisms." Whatever the exact cause of these changes, the result is that sperm are swimming too fast and too early leading to decreased fertility. Changes in Sperm Enzyme Cap Researchers have linked this aberrant pattern to infertility in other studies as well. The Buffalo study also discovered in the andrology laboratory showed that human sperm exposed to high levels of THC displayed abnormal changes in the sperm enzyme cap, called the acrosome. Testing for Sperm Count Burkman and colleagues received seminal fluid from 22 confirmed marijuana smokers and subjected the samples to a variety of tests. The volunteer subjects reported smoking marijuana approximately 14 times a week, and for an average of 5.1 years. Control numbers were obtained from 59 fertile men who had produced a pregnancy. All men abstained from sexual activity for two days before the lab analysis. From both groups, samples were tested for volume, sperm-count-per-unit of seminal fluid, total sperm count, percent of sperm that was moving, velocity and sperm shape. Long-Term Health Effects of Smoking Marijuana Marijuana Smokers Had Less Sperm Results showed that both the volume of seminal fluid and the total number of sperm from marijuana smokers were significantly less than for fertile control men. Significant differences also appeared with hyaluronic acid (an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues) and velocity, both before and after washing, were assessed, the study found. Sperm "Burnout" Is Also an Issue Results suggest that not only is marijuana use linked to decreases in the number of sperm present and amount of seminal fluid, it also leads to "burnout." Because the sperm move too fast and too early, they are unable to reach and fertilize the egg at the right time. Marijuana Use May Be Risky for Borderline Fertility Men The researchers acknowledged that many men who smoke marijuana have fathered children. "The men who are most affected likely have naturally occurring borderline fertility potential, and THC from marijuana may push them over the edge into infertility," she said. "THC remains stored in fat for a long period, so the process may be quite slow. We can't say that everything will go back to normal. Most men who have borderline fertility are unaware of that fact. It's difficult to know who is at risk. I definitely would advise anyone trying to conceive not to smoke marijuana, and that would include women as well as men." The question remains whether fertility potential returns when smokers stop using marijuana. The issue hasn't been studied well enough to provide a definitive answer. Crossing the Fertilization Signals Later research by Burkman and associates found that marijuana use can inhibit the chemical signaling processes that take place during fertilization. Marijuana use can interfere with arachidonoylethanolamide (AEA) present in human seminal plasma, mid-cycle oviductal fluid, and follicular fluid. Sperm is exposed to these reproductive fluids as they move from the vagina to the site of fertilization in the oviduct. The researchers found that AEA-signaling may regulate sperm functions required for fertilization in human reproductive tracts, and that smoking of marijuana could impact these processes. Disrupting Sperm Functions Other studies have found that marijuana use can disrupt the endocannabinoid system (ECS), which is involved in the regulation of male reproduction. A variety of in vivo and in vitro studies found that marijuana disrupts the hypothalamus-pituitary-gonadal axis, spermatogenesis, and various sperm functions. Another study of the endocannabinoid system found that marijuana can inhibit the signaling function of FAAH (fatty acid amide hydrolase) which they found has a central role in an array of reproductive signals, which plays a role in controlling several steps of sperm biology. It is obvious from these various scientific studies that marijuana use can play various roles in male reproduction and none of them improve fertility. Marijuana Can Still Cause Negative Health Problems 6 Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Rajanahally S, Raheem O, Rogers M, et al. The relationship between cannabis and male infertility, sexual health, and neoplasm: a systematic review. Andrology. 2019;7(2):139-147. doi:10.1111/andr.12585 Hsiao P, Clavijo RI. Adverse Effects of Cannabis on Male Reproduction. Eur Urol Focus. 2018;4(3):324-328. doi:10.1016/j.euf.2018.08.006 Carroll K, Pottinger AM, Wynter S, Dacosta V. Marijuana use and its influence on sperm morphology and motility: identified risk for fertility among Jamaican men. Andrology. 2020;8(1):136-142. doi:10.1111/andr.12670 Fagundo AB, De la torre R, Jiménez-murcia S, et al. Modulation of the Endocannabinoids N-Arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) on Executive Functions in Humans. PLoS ONE. 2013;8(6):e66387. doi:10.1371/journal.pone.0066387 Grimaldi P, Di giacomo D, Geremia R. The endocannabinoid system and spermatogenesis. Front Endocrinol (Lausanne). 2013;4:192. doi:10.3389/fendo.2013.00192 Zou S, Kumar U. Cannabinoid Receptors and the Endocannabinoid System: Signaling and Function in the Central Nervous System. Int J Mol Sci. 2018;19(3) doi:10.3390/ijms19030833 Additional Reading Du Plessis, SS, et al. Marijuana, phytocannabinoids, the endocannabinoid system, and male fertility. Journal of Assisted Reproduction and Genetics November 2015 Lewis, SE et al. Endocannabinoids, sperm biology and human fertility. Pharmacological Research August 2006 Schuel, H, et al. Evidence that anandamide-signaling regulates human sperm functions required for fertilization. Molecular Reproduction and Development By Buddy T Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit Get Treatment for Addiction Advertiser Disclosure × The offers that appear in this table are from partnerships from which Verywell Mind receives compensation.