New Waterproof Sunscreen Cools Skin By 11°F And Blocks UV Rays And Solar Heat 

Sunscreen has always been a staple for protecting skin from harmful UV rays, but researchers at Tsinghua University in Beijing have taken it a step further by introducing a groundbreaking sunscreen that not only blocks UV rays but also actively cools the skin.

This product can lower skin temperature by up to 6°C (11°F) compared to traditional sunscreens. The prototype was developed using radiative cooling technology, a process that dissipates heat by reflecting or emitting it away from the body. Key to this innovation is the optimization of titanium dioxide (TiO2) nanoparticle size, a component already present in mineral sunscreens. By fine-tuning these nanoparticles, the researchers achieved a formula that reflects both UV light and solar heat, providing dual benefits of sun protection and temperature regulation.

In tests, the sunscreen demonstrated SPF 50 protection, remained waterproof, and lasted for up to 12 hours under simulated sunlight exposure without losing effectiveness. Real-world trials in hot and humid conditions showed that users experienced significantly cooler skin temperatures, up to 6°C (10.8°F) lower than bare skin and 6.1°C (11°F) cooler than when using commercial sunscreens.

This innovation is particularly promising for outdoor workers like construction crews, delivery drivers, and farmers, as it could help mitigate heat stress while providing robust sun protection. The product’s formulation, which includes TiO2 nanoparticles, water, ethanol, moisturizing cream, pigments, and polydimethylsiloxane, is cost-effective at just $0.92 for 10 grams—comparable to existing sunscreens.

Another appealing feature is its customizability. Using kaolin pigments, the sunscreen can be tailored to match a wide range of skin tones, making it more inclusive and accessible.

The findings, published in the journal Nano Letters, show us the need for adaptive strategies as global temperatures rise due to climate change. Unlike cold weather, where layering clothes offers an easy solution, extreme heat poses unique challenges.