Sunscreen paralyzes sperm

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Applying lotion before sunbathing protects the skin from dangerous UV radiation. However, sun protection may have fatal consequences for men: some UV filters rob the sperm of the turbo booster that they need for successful egg cell fertilization.

Sun creams contain chemical, sometimes mineral UV filters that absorb or reflect harmful solar radiation and thus protect the skin from sunburn and skin cancer. A team of scientists from the University of Copenhagen tested the effects of these substances on healthy sperm. To do this, the researchers mixed 29 different, common UV filters with sperm from healthy donors in a buffer solution that was similar to the conditions in the female fallopian tube.

Early start

The result: 13 of the substances tested disrupted sperm function. More precisely, the ion balance of the little swimmers. This plays an important role in the fertilization of the egg cell. The female sex hormone progesterone binds to certain ion channels in the cell membrane of the sperm, causing an abrupt influx of calcium ions. And that gives the swimmers the boost they need to overcome the last hurdle.

However, some UV filters in sun creams also bind to these calcium channels and activate them too early so that the sperm has no chance once it has reached the egg cell. "Obviously the filters have hormone-like properties," says Niels Skakkebaek, head of the study. A few years ago, studies indicated that chemical UV filters have hormone-like effects on aquatic organisms. "The results are worrying and may explain in part why we have such a high rate of unexplained infertility," says Skakkebaek.

Normal amounts will do

Even small amounts of sunscreen were enough to measure an effect. “They were below the dose you would expose yourself to when you put on all the sun lotion,” says Skakkebaek. Previous studies had shown that components of sunscreen enter the blood and urine through the skin.

The 13 UV blockers complained about include common substances that can also be found in Germany in sun creams or cosmetics with UV protection, such as lip balm. These include octyl salicylate, avobenzone, octocrilen, octinoxate, oxybenzone or padimat-O. The exact effect of sunscreen on fertility can only be precisely defined after clinical studies with men. However, Skakkebaek demands that in future, before UV filters are approved, their effect on sperm should also be tested. (away)

Source: Endocrine Society press release, April 1st, 2016: Some Sunscreen Ingredients May Disrupt Sperm Cell Function.

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