A wide variety of factors can affect
male fertility
, including genetic problems, anatomical defects, hormonal abnormalities, and ingested substances, such as alcohol and marijuana. Because ingested substances are a potentially reversible factor in male fertility, 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 and is triggered when special 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), 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, exhausting itself before fertilization can take place.
Although researchers know that not all men who smoke marijuana will experience problems with fertility, 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, or 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. Many other chemicals that may impair fertility, such as cocaine, alcohol, or chemotherapy agents, interfere with testosterone production by stimulating the release of other chemicals that hamper fertility, or by directly damaging the sperm-producing cells within the testicles.
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)
To improve your chances of conceiving, see your healthcare provider for a complete checkup and 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.
