Sunscreen Side Effects May Impact Male Fertility: Study

Sperm fertility has been on the decline worldwide for decades, and new research suggests that side effects of sunscreen exposure may be a contributing factor. 

In a study presented earlier this month at the Endocrine Society’s annual meeting in Boston, researchers from the University of Copenhagen found that ultraviolet (UV) filters used in sunscreen may mimic the effect of progesterone, affecting sperm function. The findings are considered preliminary until published in a peer reviewed journal.

Researchers tested 29 of 31 UV filters approved for use in the U.S. and Europe, and they dissolved the sunscreens and applied them to sperm samples provided by healthy volunteers.

UV filters affect sperm by mimicking effects of progesterone. Since progesterone can affect sperm function, UV filters may as well. Half of the UV filters tested were found to stop sperm from functioning properly.

Progesterone plays vital role in the sperms ability to mature and fertilize a female egg. It controls the attraction of the sperm cell toward the egg, and the sperms ability to move and break through barriers to reach the egg.

Researchers explained that UV filters mimic progesterone and disrupt the entire process. UV filters have an additive effect, so even at low quantities, when the UV filters are combined together it may still affect sperm.

Many hygiene products on the market contain sunscreen additives, including body lotion, moisturizer and other products. Consumers think they are doing the right thing by protecting themselves with sunscreen and other products, but may be compounding the effects the UV filters have on the body, the researchers warned.

This is not the first study to link sunscreen to potential infertility. Research published in 2014, revealed a link between sunscreen products and infertility among men. The study showed some chemicals, like benzophenone, decrease a man’s fertility by 30%.

UV filters are easily absorbed through the skin and penetrate into the blood stream. Prior research has found UV filters in more than 95% of urine samples tested. While the accuracy of urine as a measure compared to blood is limited, it shows how abundant UV filter use is among consumers.

Researchers say this may explain, at least partly, why infertility is so prevalent. Fertility rates have fallen worldwide over last 50 years and the chemicals found in everyday products may play a large role.

Prior research has shown different endocrine disruptors may also impact the functionality of human sperm, among numerous other possible health effects

Researchers emphasized that it is still important to protect the skin from sun exposure to prevent other health problems, like skin cancer. However, there are other ways to protect the skin from the sun, including reducing sun exposure during midday hours, as well as wearing hats and other clothing to cover the skin.

While sunscreen and other endocrine disruptors may affect fertility, so do other factors, such as smoking, marijuana, excessive alcohol, and obesity. By focusing on some of the other factors, it can help reduce the overall effect on the body and fertility, experts say.