Lignin-based sunscreens show promise as sustainable UV protection

RESEARCHERS in China are developing wood-based sunscreen formulations as a more sustainable alternative to conventional products.

Two teams from the South China University of Technology (SCUT) have used lignin as a key ingredient to increase the SPF effectiveness of sunscreens.

Sunscreen is widely used to protect against ultraviolet (UV) radiation, which can lead to skin and eye damage and increase the risk of skin cancer. However, some studies have linked certain sunscreen ingredients to coral reef bleaching and other environmental impacts, prompting interest in bio-based alternatives.

SCUT’s study found that lignin-based sunscreens could match or surpass the SPF of conventional formulations, while maintaining a light colour and favourable cosmetic characteristics.

Nanotechnology

The research tested two types of lignin: a pale yellow lignin derived from poplar wood and a pale pink lignin extracted from birch. Both materials were milled and processed using ultrasonic extraction before being incorporated into moisturising cream formulations.

The poplar lignin achieved an SPF of 20 while the birch-derived lignin reached an SPF of 19. To improve performance, the researchers combined lignin with established UV filters avobenzone and octinoxate, increasing SPF values beyond 50, the upper labelling threshold commonly used in commercial sunscreens.

Human testing

The researchers are now evaluating one of the nanoparticle-based formulations in human tests to assess safety and performance.

Future work will focus on improving UV-shielding properties while maintaining “precise structural regulation” and colour.