Experts recommend applying sunscreen to protect your skin from the harmful ultraviolet rays. A new study, however, has found that in certain combinations, sunscreens may also have a harmful impact on the skin.
Published in the journal Photochemical and Photobiological Sciences, the study discovered that sunscreens that contain zinc oxide may lose efficacy after two hours in the sun. They may also become hazardous when combined with other chemicals present in most sunscreens.
According to researchers, when zinc oxide is used beneath or on top of other organic sunscreens, it does not filter as much UV radiation compared to either product alone. A mixture degrades the organic UV filters thereby not only decreasing efficiency but also producing potentially hazardous byproducts.
For the study, researchers prepared five combinations including active compounds in a sunscreen and other lotions containing zinc oxide. Two significant variations in photostability and phototoxicity were noticed. The chemical was shown to be hazardous after only two hours of sun exposure. When sunscreen becomes harmful to the skin, it exposes one to further radiation, which can lead to sunburn, blisters or sun poisoning.
Commenting on the study, Dr Sachith Abraham, consultant – dermatology, Manipal Hospital, Old Airport Road, Bengaluru, tells indianexpress.com, “As per the study, using multiple ingredients together causes issues. The drugs may be interacting with each other to create the problems. Using one ingredient like zinc oxide or titanium dioxide or other sunscreen agents in limited combination may mitigate the risk of side effects.”
“More randomised controlled studies needed to confirm the findings. We have to take a cautious approach after seeing this study, but it needs to confirmed with further studies in humans also,” he added.