Advil and Motrin, brand names for ibuprofen, a staple in medicine cabinets everywhere, may be putting male fertility at risk, according to a Danish study.

The study published this week in the Proceedings of the National Academy of Sciences found that men who took ibuprofen had disrupted production of their male sex hormones, which led to a condition called “compensated hypogonadism,” according to Business Insider.

The study looked at a small group of men — only 31 — ages 18-35 over six weeks.

The men who took ibuprofen during that time had a condition called compensated hypogonadism, which can lead to fertility issues and erectile dysfunction, according to the study. Researchers said the condition was mild in the men.

An email sent to Johnson & Johnson, the makers of both Advil and Motrin, seeking comment on the study, has not yet been returned.

But David Møbjerg Kristensen, lead author of the study at the University of Copenhagen, told The Guardian that unchecked use of the anti-inflammatory drug should be a concern for men.

“Our immediate concern is for the fertility of men who use these drugs for a long time. These compounds are good painkillers, but a certain amount of people in society use them without thinking of them as proper medicines.”