Sunscreens Can Be Linked To Impaired Sperm Function: Fertility Study

So what is the link between a sunscreen and sperms, apart from the letter 's'? Danish researchers find that some ingredients in American and European sunscreen can damage sperm cell function.

Examining 29 of the 31 ultraviolet filters in sunscreens at the U.S. and the European Union, experts from the University of Copenhagen found that a few of these chemicals disturbed the calcium signals of sperm cells. Some ingredients had effects mimicking the female hormone progesterone.

"These results are of concern and might explain in part why unexplained infertility is so prevalent," said  Dr. Niels Skakkebaek, the study's lead researcher, and professor at the University of Copenhagen.

Sunscreen can damage the function of sperms when it seeps into the skin as well as the rest of the body. Looking at urine and sperm samples helped scientists to discover ultraviolet-filtering chemicals in all the urine as well as some blood samples.

Studying how the UV-filtering chemicals influence healthy sperm, researchers tested sperms in a buffer solution simulating conditions in female fallopian tubes. Skakkebaek and his team wanted to study calcium signalling, especially the sperm-specific calcium ion channel called CatSper.

Experts explained that the CatSper channel can bind to the progesterone in order to control sperm cell fertilization functions like sperm motility.

About 45 percent of the 29 UV filters were found to interfere with sperm function. About 13 UV filters set off a surge in the movement of calcium ions in the sperm cells when it bound with progesterone.

"This effect began at very low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens," said Skakkebaek.

Experts found that nine of the 13 UV filters impairing sperms were imitating the effects of progesterone, which showed that UV filters tend to put the body's endocrine system into disarray.

All the UV filters have been approved by the U.S. and the European Union for use in sunscreens.

"Our study suggests that regulatory agencies should have a closer look at the effects of UV filters on fertility before approval," Skakkebaek said.

The findings will be presented at the annual Endocrine Society conference in Boston, Mass., which will be held from April 1-4.