There are many medications that can lower a sperm count or even stop sperm production. Today I would like to discuss the detrimental effects of testosterone supplementation on a man’s sperm production.
In my practice, I have cared for many patients whose partners have fathered children easily in the past but who have now been found to have no sperm in their semen. In these cases, men may undergo a semen analysis. When questioned, many of these men admit that they have picked up a new vice of taking testosterone or a steroid that mimics testosterone (anabolic steroids).
Testosterone is needed in high concentrations to stimulate spermatogenesis (production of sperm) within the testes. Some men are taking the steroids to improve weight training leading to muscular growth. Other men reason that if they take testosterone, they will make more sperm. In fact, taking testosterone has the opposite effect on sperm production. Taking testosterone or hormones that mimic testosterone (anabolic steroids) in high enough doses, and for a prolonged period of time, will stop the testicles from producing sperm!
Let me explain how this works. The testes are controlled by 2 main hormones: FSH (follicle stimulating hormone) and LH (luteinizing hormone). These hormones are made by the anterior pituitary.
Think of the pituitary like a thermostat. Thermostats sense their surrounding temperatures and turn on and off accordingly. For example, during the summer, if the temperature of a room gets too hot, the thermostat senses this and turns on the cool air. If the room gets too cold, the thermostat senses this as well and turns off the cool air.
The pituitary works in the same manner. If the pituitary senses that there is not enough testosterone present, it sends more LH to the testicles so that they will produce more testosterone. Likewise, if the pituitary senses that there is too much testosterone present, it will decrease or even stop production of LH leading to a depressed testosterone production or a total cessation of testosterone all together.
However, if the testosterone production stops, so does the sperm production. So, men who take testosterone supplementation or steroids that mimic testosterone will depress sperm quantity. If men take testosterone in high enough doses and for a prolonged period of time, sperm production can be completely turned off, leading to a complete absence of sperm in the semen.
Fortunately, once a man stops taking the testosterone or hormone that mimics testosterone, the pituitary senses that there is a lack of testosterone in the system and restarts sending LH to the testes. This in turn restarts the production of sperm. Depending on how long and how high of a dose of testosterone taken, a healthy amount of sperm can be available within about 2-3 months. Unfortunately, some men who have been taking testosterone in high enough dosages and for a prolonged period may never be able to resume sperm production.
If you are having trouble getting pregnant, ask your partner to consider testing for male infertility. If your partner has no sperm in his semen and he is taking testosterone supplements or anabolic steroids, or even over the counter work out supplements (which can contain hormones that mimic testosterone), ask your doctor what the next steps should be in order to return his sperm count back to normal.
Sources: Speroff L, Fritz MA, Clinical Gynecologic Endocrinology and Infertility, 8th ed. Philadelphia: Lippincott Williams & Wilkins, 2010: 1249-92.
Dr. Lowell T. Ku, M.D. is an award winning and leading Reproductive Endocrinology and Infertility specialist at Dallas IVF, one the nation’s premiere infertility centers. Doctor Ku clarifies the many confusing terms used in the world of Infertility using straightforward explanations.