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Effects of Marijuana on Sperm Motility

June 10, 2008 - 7:30am
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Effects of Marijuana on Sperm Motility

Image for marijuana and 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)

What Can You Do?

To improve your chances of conceiving, see your healthcare provider for a complete checkup. Use the visit to talk over healthy lifestyle choices such as:

  • Quit smoking.
  • Stop using marijuana or any other recreational drugs.
  • Reduce your consumption of alcohol.
  • Maintain a reasonable level of exercise activity—exercising too intensively may decrease fertility.
  • Discuss any antibiotics you have been taking and their potential impact on your fertility.
  • Avoid environmental poisons and hazards, including pesticides/insecticides, organic solvents, lead, ionizing radiation, heavy metals, and toxic chemicals.
  • Discuss the possible benefits of the supplement carnitine, which is showing increasing promise in studies as a treatment for male infertility.


American Society for Reproductive Medicine

Urology Health


BC Health Guide

Health Canada


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BUPA investigative news. British United Provident Association website. Available at: http://www.bupa.co.uk/health_information/html/health_news/211003sperm.html. Accessed December 14, 2003.

Highlights from the American Society for Reproductive Medicine 59th Annual meeting. American Society for Reproductive Medicine website. Available at: http://www.asrm.org/Media/Press/ext_fac_maleinf.html. Accessed December 14, 2003.

Nudell D, Monoski M, Lipshultz L. Common medications and drugs: how they affect male fertility. Urologic Clinics of North America. November 2002;29:965-973.

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The Surgeon General’s warning on marijuana. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/00001143.htm. Accessed December 14, 2003.

Ng CM, Blackman MR, Wang C, Swerdloff R. The role of carnitine in the male reproductive system. Ann NY Acad Sci. 2004;1033:177-188.

Garolla A, Maiorino M, Roverato A, Roveri A, Ursini F, Foresta C. Oral carnitine supplementation increases sperm motility in asthenozoospermic men with normal sperm phospholipid hydroperoxide glutathione peroxidase levels. Fertil Steril. 2005;83:355-361.

Balercia G, Regoli F, Armeni T, Koverech A, Mantero F, Boscaro M. Placebo-controlled double-blind randomized trial on the use of L-carnitine, L-acetylcarnitine, or combined L-carnitine and L-acetylcarnitine in men with idiopathic asthenozoospermia. Fertil Steril. 2005;84:662-71.

Last reviewed March 2008 by ]]>Rosalyn Carson-DeWitt, MD]]>

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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