Here are a few facts that appear unrelated:
- Athletes sometimes have weird endocrine profiles (low testosterone levels, messed up testosterone-to-luteinizing hormone ratios, etc.).
- The preferred pain reliever of most athletes is ibuprofen, aka Advil.
- Fertility rates in the Western world continue to decline, year after year.
Now, those who worship at the altar of logic know that causality doesn't imply correlation, but a recent study of the effects of ibuprofen on the physiology of human testicles makes you think there's plenty of cause to be correlatin' the facts listed above.
Researchers at University of Texas Southwestern Medical Center found that relatively short-term use (14 days) of ibuprofen can induce a state of "compensated hypogonadism" in human males. That's a condition where men have normal levels of testosterone but higher levels of luteinizing hormone (LH), which is the stuff that stimulates the testicles to produce testosterone.
What that means is that your balls start to act like old men themselves. LH knocks on the chemical door throughout your life and when you're younger, your balls "hear" the knock and answer the door (make more testosterone).
When you're old, your balls don't hear the knocking and keep watching reruns of CSI. LH has to knock louder and louder (send more and more LH) for the balls to hear, but oftentimes, they don't and fall asleep in the Barcalounger.
The doctors found that regular use of ibuprofen can bring about this condition way early. It's a problem because conditional hypogonadism is often followed by real hypogonadism (low testosterone and all its related ailments).
But that's not all. They also found that regular use of ibuprofen affects other aspects of testicular function, including a diminished sperm count.
This study was a bit unusual (but admirable) in that they tested the effects of ibuprofen on both real live young men and in adult testicle explants from donors (ex vivo). They also did some additional testing in test tubes (in vitro).
First, they gave a daily 600-mg. dose of ibuprofen to young, healthy volunteers and evaluated their testicular physiology after 14 days and again after 44 days. They also exposed the testicular samples to doses that were equivalent to the oral doses given to the young men, testing them at 24 hours and again at 48 hours.
The ibuprofen didn't affect the testosterone or estradiol levels of the young men at all, either after 14 days or 44 days. However, it did affect their LH levels and their LH/free testosterone levels. LH increased by 23% after 14 days and 33% after 14 days, in effect creating a state of conditional hypogonadism (explained above).
Further, the ibuprofen affected Sertoli cell activity, and that's where sperm cells are made. Specifically, it reduced inhibin B/FSH ratios by 4% after day 14 and 12% after day 44, along with reducing AMH levels by 9% after day 14 and 7% after day 44. Add 'em up and it means potentially gimpy sperm and not many of them, to boot.
The results in the ex vivo samples were even more dramatic. Testosterone levels dropped after administrating ibuprofen. The effects were dramatic, dose-dependant, and worsened with time. In fact, ibuprofen "generally inhibited all steroids from pregnenolone down to testosterone and 17B-estradiol."
The samples of testicular tissue also suffered impaired Sertoli cell function, which was also seen in the testicles of the human subjects. (The impairment to the testicles is likely reversible upon cessation of ibuprofen use, though.)
Lots of athletes use ibuprofen to ease their aches and pains. More and more evidence suggests that this is bad strategy. For one, it's almost unequivocal that ibuprofen, along with other NSAIDS, impairs the post-exercise acute inflammatory phase, which is crucial to muscle growth.
As such, taking ibuprofen to quell annoying pain allows you to work out harder, but the drug also prevents you from growing additional muscle.
Furthermore, indiscriminate and excessive use of ibuprofen might actually be harming the testicles' ability to make sperm, thus contributing to falling male fertility rates. The researchers went so far as to say that the striking dual effect of ibuprofen on Leydig and Sertoli cells suggests that ibuprofen, of all the chemical classes considered, has "the broadest endocrine-disturbing properties identified so far in men."
Not good. As always, more studies are needed, but in the meantime, use something like the polyphenol curcumin for post-workout pain management. It does the job without affecting testicular physiology or muscle adaptation to exercise.
- Kristensen DM et al. Ibuprofen alters human testicular physiology to produce a state of compensated hypogonadism. PNAS. 2018 Jan;115(4):E715-E724.