The other day a patient came to see me who looked like the picture of health. He was tan and wore a tight-fitting polo shirt that revealed a heavily-muscled torso. But his testicles were small and soft, and he and his wife had been trying without luck for more than a year to have kids. His wife was checked out and everything seemed fine on her end. So what was going on?

 

I immediately suspected the man was using some kind of supplement to boost his testosterone and build muscle mass. A couple of days later when his blood work came back it was obvious: his testosterone level was 3 times higher than normal. Bingo. Without knowing it, this guy had effectively sterilized himself. Unfortunately, this guy is not alone. Hundreds of thousands of men are compromising their fertility in their quest for bigger muscles, better athletic performance, or better sex.

 

Here’s what happens. Every guy’s brain is equipped with a tiny testosterone “thermostat” that constantly monitors the level of this key hormone in his blood. When levels fall, the brain sends signals to the testicles to boost production, and when levels rise, signals tell the testicles to shut down. Adding extra testosterone tricks the brain. Sensing the high levels, the brain shuts down testosterone production and sperm production, both of which happen in the testicles. As a result the testicles shrink, soften, and the man’s fertility plummets. He may still have normal erections and orgasms, so he probably won’t realize anything’s wrong, but he’ll be shooting blanks.

 

When I explained all of this to my patient, he was shocked.  He had no idea. He agreed to stop taking the supplements he was using and I prescribed a medication to help kick-start his body’s natural testosterone production machinery. His sperm count will probably start to return to normal in three months or so. If his experience is like my other patients who have unwittingly sterilized themselves with supplements, he should be none the worse for wear in 6 months and his chances of having children should be normal.

 

The problems with testosterone supplements apply even to supplements such as dehydroepiandrosterone (DHEA) and androstenedione.  These substances get converted to testosterone in the body, so all of the risks noted above apply to them. The array of products now available is so huge and the number of brand names so large that a comprehensive list isn’t feasible. In general, however, any supplement containing the following ingredients or which include the following words should be suspect:

• testosterone
• dehydroepiandrosterone (DHEA)
• androstenedione
• androstenediol
• prohormone
• prehormone
• “hormone”
• “anabolic”

 

The safest approach is to avoid all nutritional supplements if you are trying to have a baby because many contain hormones or hormone precursors that can hurt fertility and ingredients are often labeled in deceptive ways.