A new study has found a possible link between ibuprofen and male infertility.
The small study, published on Jan. 8 by the Proceedings of the National Academy of Sciences journal, found that a small sample of young men who took ibuprofen in doses that are used by athletes became more likely to develop a hormonal condition in middle age linked to infertility, according to CNN.
Ibuprofen, an NSAID (non steroidal anti-inflammatory drug), is used for minor pain relief and to reduce a fever, and is sold under brand names including Advil and Motrin.
Mike Tringale, a spokesman for the Consumer Healthcare Products Association, said the association "supports and encourages continued research and promotes ongoing consumer education to help ensure safe use of OTC medicines."
"The safety and efficacy of active ingredients in these products has been well documented and supported by decades of scientific study and real-world use," added Tringale.
The newly released findings are a continuation of a study that examined the effects of ibuprofen, aspirin, and acetaminophen, which is sold under the brand name Tylenol, on pregnant women. That study found that each of the three pain relieving medicines had an affect on male babies' testicles when their mothers took them during pregnancy.
The three drugs were found to be "anti-androgenic," said David M. Kristensen, the study's co-author and Copenhagen University Hospital senior scientist. This reportedly means that they have an effect on male hormones.
For the more recent study, which took place in Denmark and France, the research team used a sample of 31 males between 18 and 35, 14 of which took up to 600 milligrams of ibuprofen twice per day over a six-week period, and 17 of which were given a placebo.
The group who took ibuprofen saw a decrease in their ratio of testosterone to luteinizing hormones. The hormonal imbalance is reported to have led to compensated hypogonadism, which is linked to depression and decreased fertility.
The study's authors reported a "univocal depression of important aspect of testicular function, including testosterone production, after use of over-the-counter ibuprofen," according to USA Today.
According to Bernard Jegou, the Institute of Research in Environmental and Occupational Health in France director and study co-author, the effects on the study's volunteers who took ibuprofen for only a short time were reversible. He said it's unclear whether the effects are also reversible for those who have used ibuprofen regularly in the long-term and that more study is needed. It is also unclear whether the same anti-androgenic effects are seen at lower doses.
"If this serves to remind people that we are really dealing with medical drugs -- not with things which are not dangerous -- this would be a good thing," added Jegou.