No Fun in the Sun: Sunscreen Blamed for Poor Sperm Quality

According to scientists at the international research center Edmarc at Rigshospitalet in Copenhagen, Denmark, men's sperm contains far less spermatozoa that it used to some 70-80 years ago. This is at least partially blamed on chemical UV filters associated with reproduction disorders in animals and potentially affecting the quality of human sperm as well.

"UV filters are among the potentially hormone-destructing chemicals we are exposed to, but they tend to be overlooked in research," Edmarc Research Director Anna-Maria Andersson told the Swedish daily Svenska Dagbladet.

Edmarc researchers found that 13 of the 29 UV filters approved for use in sunscreen in the EU and the US affected the sperm in a manner similar to the female hormone progesterone, which is used as a homing signal to swim towards eggs, which leads to fertilization failures, Professor Niels Skakkebaeck noted. If the UV filters make spermatozoa confused, it could hypothetically be one of the reasons why and more couples seek help for infertility.

Furthermore, at least four of these sperm-affecting UV filters are known to pass through the skin and into the bloodstream. Once a substance is present in the blood, it may affect the body. In addition, mixing small doses of different UV filters that in itself do not interfere with sperm cells gave the same effect.

"This means that together these substances can have a cumulative effect, even if they occur in very low concentrations, a so-called 'cocktail effect,'" doctoral student Anders Rehfeld said.

Åke Bergman, a professor of Environmental Chemistry and Head of the Swedish Center for Toxicology (Swetox), was not the least amazed by the Danish findings.

"We all know that the skin is a bad barrier for many substances. When applying sunscreen, skin cream or cosmetics, there is a significant danger that substances in them will then proceed into the body," Åke Bergman said.

Just to show how wide-spread UV filters are, nine out of ten children exhibited measurable levels of at least one UV filter in their urine in the summertime. To the researchers' surprise, however, many also measured traceable UV filter levels even in winter, which Anna-Maria Andersson ascribed to the same substances being used in food packaging, plastics, paints and textiles. A further study revealed that young women aged 16-21 had the highest levels of UV filters, which once again was attributed to cosmetics, such as night cream.

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