As New Scientist recently reported, lignin, a natural polymer derived from wood, has gained significant attention as a sustainable and effective ingredient for sunscreen formulations — boosting SPF values to 180+, per the source. Similarly, C&T previously reported that lignin can increase SPF as well as reduce the need for traditional UV filters and address the white cast issue.
In recent months, several advances in lignin-based sunscreens have been published, demonstrating their potential to revolutionize UV protection. Following are four examples.
Pink Birch Lignin for SPF 180+ Broad-Spectrum Protection
A study published in ChemSusChem describes how pink lignin can be extracted from birch in such a way as to retain its natural UV-blocking properties while addressing the challenge of its dark color. To address its limited long-wave UV absorption, the lignin is then encapsulated with chemical sunscreen actives. Incorporation of the lignin into sunscreens achieved SPFs of 130+ and 180+, researchers reported. The formulations also demonstrated good photostability, with only an 18% reduction in SPF after 7.5 hours of UV exposure.
Grafted Lignin Spheres for Clearer, High-SPF Sunscreens
Research reported by EurekAlert!, from the Journal of Bioresources and Bioproducts, highlights a novel approach to modifying lignin by grafting benzotriazole side chains. This process produces beige-colored particles with enhanced UV-blocking capabilities. When combined with titanium dioxide, SPFs of up to 66 were achieved while maintaining transparency on the skin.
Lignin Nanoparticles for Natural-Based Sunscreens
Another study worth highlighting, from the journal Carbon Resources Conversion, investigated the use of lignin nanoparticles as additives to develop natural-based sunscreens with high UV protection. The research highlighted the significant improvement in SPF achieved by incorporating lignin nanoparticles, as opposed to the original lignin oligomers, into sunscreen formulations — reportedly due to the more exposed chromophore on the surface. This study also underscored the potential of lignin nanoparticles to replace synthetic UV filters, reducing environmental impact while maintaining high performance.
Lignin Nanoparticles from Softwood and Hardwood for Broad-Spectrum Protection
Finally, a recent study published in Wood Science and Technology explored lignin nanoparticles derived from spruce and eucalyptus kraft lignins as sustainable additives for sunscreen formulations. The research emphasized their effectiveness in providing broad-spectrum UV protection and enhancing sunscreen performance; spruce being the more effective of the two. Furthermore, the study highlights the versatility of lignin nanoparticles, e.g., improving emulsion stability.
Implications and Future Directions
These advancements in lignin-based sunscreens demonstrate their potential as a sustainable and effective alternative to traditional UV filters.
Future research could focus on scaling up production methods, improving the aesthetic qualities of lignin formulations, and exploring additional applications in cosmetics and other industries.
