The study - conducted by a team of researchers in Denmark and France - was placebo-controlled and recruited 31 healthy white males between the ages 18 and 35 years.
However, despite the change in LH levels, the men's testosterone levels didn't change. To compensate, the pituitary gland stimulates production of more testosterone - but eventually, the mechanism wears out and levels of the hormone drop throughout the body.
The researchers found that prolonged ibuprofen use suppressed "important aspects of testicular function, including testosterone production".
The study is a continuation of previous research on pregnant women linking mild ibuprofen exposure in fetuses to an increased risk of inherited medical conditions, testosterone blockages, and physiological effects on the testicles of male babies.
Half the group took 600mg of ibuprofen twice a day - the maximum recommended dose in the U.S.is 800mg up to four times a day - for 2 weeks.
It is known to increase the risk of heart attacks and stroke if taken regularly in high doses for a long time.More news: Trump to Attend Davos Economic Forum
All 3 drugs are considered anti-androgenic, meaning they disrupt male hormones..
Several experts have reacted to the study findings.
The researchers also pointed out the risk of those with compensated hypogonadism progressing to overt primary hypogonadism, which is characterized by "low circulating testosterone and prevalent symptoms including reduced libido, reduced muscle mass and strength, and depressed mood and fatigue".
Now, before you panic, there's no suggestion yet that occasionally relying on an ibuprofen will make your balls shrivel up and die. The consistency of the results, however, as well as the earlier epidemiological results, suggest that there might really be an issue here. Professional athletes, however, do tend to take ibuprofen frequently, so this research could spark a serious look into the way those under physical strain treat their aches and pains.
"The study shows that ibuprofen use results in selective transcriptional repression of endocrine cells in the human testis", the significance on the PNAS site reads.