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Experts claim EHMC in sunscreens can damage DNA

An active substance in some sunscreens is unstable when subject to UV light.

Ethylhexyl methoxycinnamate also known as EMHC, an active substance in some sunscreens and other personal care products intended for daily use, is unstable when subject to UV light and undergoes a transformation that can cause damage to the DNA in human cells.

This crucial discovery has been announced by the experts from the Research Centre for Toxic Compounds in the Environment (RECETOX) at Masaryk University. They also add that the substance is gradually being phased out, especially in sunscreens.

Although EHMC is used as protection against harmful radiation from the sun, it is not immune to its effects as the UV light changes the spatial arrangement of the EMHC molecules. This process is called isomerization. Isomers are substances with the same number of atoms and hence the same chemical formula, but a different spatial arrangement, which can affect their properties.

“While the characteristics of the original form of EHMC have been investigated, the biological impact of its isomer has not,” says Pavel Čupr, the leader of the expert team.

This led RECETOX researchers to initiate a study, which confirmed that the substance has a significant genotoxic effect under laboratory conditions. “This means that it is capable of damaging human DNA and potentially cause genome mutations that could be the cause of serious diseases,” says Anežka Sharma, a PhD student who participated in the study.

These are the findings of a series of tests that the experts used to examine the impact of the transformed EHMC on the trigger mechanisms of DNA repair and any potential direct damage it might cause to the genetic information in the cells.

Genotoxicity was tested on both bacterial and human cells, including liver stem cells. The results of the tests on bacteria were available and published first. A further search for personal care products that contain EHMC revealed that their number on the market has gradually been falling.

The compound is present not only in sunscreens but also in other cosmetic products for daily use as it helps protect against damage caused by sunlight during storage and use. This is why it can also be found in face creams including night creams, hair sprays, and perfumes.

According to Pavel Čupr, the research results show that the use of this substance needs to be reassessed and he intends to make sure that the decision makers – such as the EU institutions that have the impact of substances on humans on their agenda – are made aware of the findings.