Sunscreen and Sperm: Can Chemical UV Filters Alter Sperm Function?

In an article published online on September 1 in Endocrinology, Rehfeld et al discussed their results after testing 29 UV filters. They found that 13 of 29 filters tested had in vitro effects on Ca²⁺: 4-methylbenzylidene camphor, 3-benzylidene camphor, menthyl anthranilate, isoamyl p-methoxycinnamate, ethylhexyl salicylate, benzylidene camphor sulfonic acid, homosalate, ethylhexyl methoxycinnamate, octcrylene, butyl methoxydibenzoylmethane, and diethylamino hydroxybenzoyl hexyl benzoate.

This study was prompted by a prior study by Schiffer et al (EMBO Rep. 2014;15:758-765) on multiple endocrine disrupting chemicals of which 33 of 96 tested chemicals induced Ca²⁺ signals in human sperm cells in vitro. Of these previously tested chemicals, some of the chemical sunscreen filters were the most potent, leading to the current study.

Rehfeld et al sought to determine how the UV filters affected calcium signaling, which is a pathway that is essential for sperm cells to be able to swim healthily. These calcium-signaling pathways usually are triggered by progesterone, but the authors showed that 13 of 29 UV filters (45%) also commenced calcium signaling. This effect began at low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens.

What’s the issue?

Are these chemical UV filters mimicking progesterone in vivo and could it be interfering with sperm motility? A suboptimal progesterone-induced Ca²⁺ influx has been associated with reduced male fertility and CatSper (cation channel of sperm) is essential for male fertility (Hum Reprod. 1995;10:120-124).

The UV filters tested are widely available in Europe and the United States. Although this study was in vitro, the in vivo effects will need to be explored. It has been reported by Chivsvert et al (Anal Chim Acta. 2012;752:11-29) that some UV filters can be transcutaneously absorbed into bodily tissues, which could be potentially important for men trying to conceive or for reproductively challenged couples.

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