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Marijuana and Male Fertility – What You Need To Know

ohn S. Rinehart, M.D., Ph.D., JD

It is very likely that Illinois will soon be the 11th state to legalize recreational marijuana or cannabis but what about the impact of cannabis on male fertility?  Dr. John Rinehart, founding partner at Reproductive Medicine Institute, with offices in Bloomingdale, Oak Lawn, and Evanston explains more about the relationship between cannabis and male fertility.


Cannabis has been around a long time but recent changes in legislation and societal attitudes has led to a rise in the use of cannabis. However, now that so many people are using cannabis, and many legally, efforts are underway to accurately determine the dangers and benefits of cannabis use.


One area receiving increasing attention is the effect of cannabis use on male fertility. Unfortunately, there is very little well-done research in the newly expanding research area of male fertility and cannabis use. While there is much to learn about the interaction of cannabis and male fertility, there is information available that might help people decide about their use of cannabis if they are trying to conceive.


What is cannabis?


Cannabis is a psychoactive drug derived from the hemp plant, Cannabis Sativa. Cannabis has been used for centuries, having been found in Egyptian mummies, and Marijuana, Hashish, Bhang, and Ganja are the most widely used illegal drugs in the world.

The leaves, stems, and flower buds of the plant are used for marijuana whereas, resin form the flower is used to make hash. Poles from Yahoo News and Gallup report that over half of all Americans have tried marijuana with the Yahoo report reporting that 33 million people use pot at least once or twice per months. The report estimated that as many as 55 million Americans identified themselves a “current users” which is almost as many Americans that smoke cigarettes (59 million). The cannabis plant produces over 421 chemicals of which only a fraction (61) are cannabinoids (derived from the cannabis plant).


Smoking the plant alters these basic chemicals so that in the end over 2000 chemicals are produced. Cannabinoids react with a number of cells in many different organs. The cannabinoid will attach to a protein called a receptor and it is the receptor which directs the action of the cannabinoid on the cell’s function. Two receptors for cannabinoids are called CB1 and CB2. CB1 is found in the brain in areas that are associated with memory, cognition, anxiety and pain. CB2 receptors are found in the spleen and other areas outside of the brain and may explain the effect of cannabinoids on the immune system.


Cannabis has both psychological and physiological effects which include feelings of euphoria, lack of concentration, and relaxation. Physiological effects include changes in blood pressure, dry mouth increased appetite and slowed respiration. Cannabis does affect the same reward system which is affected by alcohol, cocaine, and opioids and thus cannabis can be addictive is a similar fashion to the other drugs.


Sperm recognize cannabinoids.


Sperm have both CB1 and CB2 receptors which are located on the tail, the midpiece and part of the head of sperm. Both CB1 and CB2 receptors have also been found on Sertoli cells. Sertoli cells are helper cells responsible for sperm maturation.


Cannabinoids can affect sperm production by interacting with CB1 receptors found in the brain. Endocannabinoids have been found to lower LH levels. LH is necessary for proper functioning of the Leydig cells in the testes. Leydig cells produce testosterone and lower levels of LH lead to lower levels of testosterone. Males have a different expression of CB1 receptors and thus are more sensitive to cannabinoids.


Recently, research has focused on the process of methylation of DNA. The DNA code provides a blueprint for how a human is constructed and is passed from generation to generation largely in an unaltered form. However, how the code is interpreted varies between individuals and can be affected by environmental factors. This gives the system the core stability of the DNA but provides for flexibility to adapt to short term environmental influences. A chemical structure, termed a methyl group, can be attached or removed from the DNA chain which affects how the DNA is interpreted. Thus, knowledge about the methyl status of the DNA may provide information about how obesity, smoking cigarettes and smoking cannabis affect human functioning.


Recent research has demonstrated the cannabis does alter the methylation status of DNA in sperm. Sperm fertilize eggs by being brought into the egg and thus the altered DNA is used to form the DNA of the fertilized egg. Usually, the methylation status of this early embryo is reprogrammed, and the influence is limited. However, it has now been discovered that much less of the DNA has its methyl groups removed and thus the paternal influence may persist in the infant.


Does cannabis affect sperm?


The short answer is yes. Almost all semen characteristics are affected to the negative by cannabis. Research is conducted on both animals and humans. Animal and human studies demonstrate a reduction in sperm concentration. The shape of sperm has been found to be affected by cannabis.


Perhaps the best studied sperm characteristic is motility. Here a hypothesis is that by binding to the CB1 receptor, cannabis reduces the ability of the mitochondria to produce energy. Sperm need energy to move so a reduction in the sperm’s energy supply will result in a reduced motility. Not only do sperm have to reach an egg in the fallopian tube but they have top enter the egg and initial development of the embryo. Cannabis may reduce the ability of sperm to fertilize but this is not well established yet.


Most importantly: does cannabis use decrease conception?


Honest answer: don’t know. There is no credible, large study that addresses this issue. That is truly disappointing. So, what is a couple to do? Much like alcohol and cigarette smoking, cannabis might decrease a couple’s change of conceiving. So, until better evidence is obtained, prudence would say to use these substances in moderation if at all. This would be particularly true for a male with a reduction in the semen characteristics.


If you are experiencing difficulty getting or staying pregnant, our expert team at RMI wants to help with seven convenient Chicagoland locations in: Bloomingdale, Northbrook, Chicago, Oak Brook, Oak Lawn, Evanston and Elmhurst. Contact us today at 630-403-0074 or send a message here.