Effects of Marijuana on Sperm Motility

A wide variety of factors can affect ]]>male fertility]]>. Genetic problems, physical defects, hormonal abnormalities, and substances that are taken such as alcohol and marijuana are just a few. Because substances are a potentially reversible, study of this factor is particularly interesting and important.

Some fascinating recent research has looked at how marijuana may affect male fertility. Researchers at the University of Buffalo examined sperm from men who had smoked marijuana on a regular basis for an average of five or more years. Sperm samples revealed a number of significant abnormalities:

• Decreased number of sperm (sperm count)
• Low volume of seminal fluid (the ejaculatory fluid that carries the sperm)
• Abnormally formed sperm
• Abnormal patterns of sperm movement (sperm motility)

In particular, the researchers looked closely at the abnormal patterns of sperm motility. In order to fertilize an egg, sperm must “swim” up the female reproductive tract. Normally, just as the sperm approaches the egg, it begins to swim more vigorously. This is called hyperactivation. It is triggered when chemicals called anandamides bind to special receptors on the sperm cell. Under normal conditions, hyperactivation allows the sperm to swim vigorously enough to successfully fertilize the egg.

Researchers have determined that the same special receptors that accept anandamides also accept tetrahydrocannabinol (or THC). THC is the major active chemical in marijuana. Researchers believe that when a man smokes marijuana, THC binds to the anandamide receptors on the sperm and causes it to enter hyperactivation too early. The sperm exhausts itself before fertilization can take place. 

Researchers know that not all men who smoke marijuana will experience problems with fertility. However, they suspect that marijuana smokers who already have somewhat borderline fertility are the most likely to experience problems. Furthermore, researchers have yet to determine how long THC is stored in body fat. It is also unclear whether sperm motility will ever completely return to normal after an individual stops smoking marijuana.

These recent discoveries about the direct effects of THC on sperm are unique. Chemical like cocaine, alcohol, or chemotherapy agents, interfere with testosterone production by directly damaging the sperm-producing cells within the testicles or by stimulating the release of other chemicals. These chemicals hamper fertility.

Additional substances that may impair male fertility include:

• Opiate drugs
• Cigarette smoking
• Certain antibiotics (nitrofurantoin, erythromycin, tetracycline, gentamycin, neomycin)
• Cimetidine (anti-ulcer drug)
• Cyclosporine (antirejection drug used after organ transplants)
• Antigout medicines (colchicines, allopurinol)
• Sulfasalazine (medication for inflammatory bowel disease)
• Anabolic steroids (the type of steroids used by bodybuilders, athletes)