A recent study conducted at the Copenhagen University Hospital reports that a number of UV filters found in sunscreens disrupt sperm cell function. 13 out of 29 UV filters (found in sunscreens on the market in the US and European Union) were found to increase calcium ion influx in sperm cells to disrupt the fertilization process, and 9 of the 13 did so by mimicking the female hormone, progesterone.


Sunscreen has always been highly praised and recommended for protection from the sun’s ultraviolet (UV) radiation. UV filters (compounds in sunscreen) absorb UV rays and effectively block UV rays from penetrating the skin and causing DNA damage, thereby preventing skin cancer. While UV filters normally provide protection from UV ray absorption, UV filters themselves are absorbed by the skin and new research suggests that their absorption may cause some negative side effects.

Previous research shows that UV filters have been found in human blood samples and also in 95% of urine samples. Now, researchers at the Copenhagen University Hospital have discovered that some UV filters found in common sunscreens disrupt sperm cell function in humans. Researchers tested 29 different UV filters, (all of which are allowed in sunscreens in the US or in the European Union), on live, healthy human sperm cells. Sperm cells were tested in a solution that resembled the conditions of female fallopian tubes and observations were made once UV filters were added.

Researchers discovered that of the 29 UV filters tested, 13 (45%) induced an increase in calcium ion influx into the sperm cells. Calcium ion levels play a major role in sperm cell function. Researchers also found that of the 13 UV filters which caused increased levels of calcium, 9 of them were able to activate calcium influx through the CatSper calcium ion channel, by mimicking the effects of progesterone. CatSper is responsible for male fertility and is the main sperm receptor for progesterone (a female hormone). When progesterone normally binds to CatSper, it causes a temporary influx of calcium ions and activates several sperm functions required for sperm motility and egg fertilization.

The effects of UV filters on sperm cell function were present even at low levels of UV filters; much lower than the levels present when we apply sunscreen to our whole body. Researchers suggest that these UV filters are “endocrine disruptors” and hope that their results encourage the formation of clinical trials where fertility is considered when testing sunscreen. Of the 13 UV filters which mimic progesterone, 8 are already approved for use in the US and are found in many sunscreens, make up, moisturizers, and lip balms. Watch out for these 8 progesterone-mimicking UV filters in your US sunscreen: avobenzone, homosalate, meradimate, octisalate. octinoxate , octocrylene, oxybenzone, padimate O.




Written By: Alexandra Lostun, BSc

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