Danish and French researchers say the use of Ibuprofen can alter the testicular physiology of men and consequently lead to infertility.
The researchers said other analgesics like Paracetamol might also lower fertility but they only focused on Ibuprofen because of its increasing popularity.
Previous research by the team, which focused on pregnant women, had found that the use of Paracetamol and Ibuprofen during pregnancy affected the testicles of male babies.
In addition to producing sperm, the testicles secrete testosterone, the primary male sex hormone.
David Kristensen, study co-author and senior scientist at department of neurology at Copenhagen University Hospital, said the drugs disrupt male hormones.
“The three drugs even increased the likelihood that male babies would be born with congenital malformations,” he said.
The team used 31 male volunteers between the ages of 18 and 35.
14 of them were given daily doses of Ibuprofen, which professional and amateur athletes take. The remaining 17 volunteers were given a placebo.
Within 14 days, the luteinising hormones of men taking Ibuprofen, which are secreted by the pituitary gland and stimulate the testicles to produce testosterone, became coordinated with the level of ibuprofen circulating in their blood.
At the same time, the ratio of testosterone to luteinising hormones decreased, which is a sign of dysfunctional testicles.
This resulted in hypogonadism, which is associated with infertility and increased risk of cardiovascular diseases like stroke and heart failure.
Bernard Jégou, co-author and director of the Institute of Research in Environmental and Occupational Health in France, said the short-term effects in males are reversible but it is not known if the long-term effects are reversible.
The study was published on Monday in the journal Proceedings of the National Academy of Sciences.