Mineral sunscreen developed at UCLA reduces visible white cast

UCLA researchers engineered tetrapod-shaped zinc oxide for mineral sunscreen that produced about SPF 30 in tests and appeared warmer on skin, reducing the white cast seen with conventional zinc oxide formulas.

UCLA researchers have developed a mineral sunscreen that uses tetrapod-shaped zinc oxide particles to address the white, chalky cast common to many mineral sunscreens. The change in particle shape led to formulations that appeared warmer and closer to natural skin tones in laboratory tests and controlled skin applications. At the same zinc oxide concentration, the tetrapod-based lotions achieved about SPF 30 and remained more stable over time. This work is being discussed because improving cosmetic acceptance could affect how consistently people use sunscreen, which relates to efforts to prevent skin cancer. Key findings: - The team tested zinc oxide made by a patented high-temperature flame process that yields larger, four-armed "tetrapod" particles rather than the usual round nanoparticles. - Tetrapod particles form porous networks and resist clumping, which helps them stay evenly distributed in sunscreen formulas. - Sunscreens formulated with these tetrapods reached roughly SPF 30 at the same active concentration as conventional zinc oxide. - The tetrapod formulations showed fewer signs of separation or thickening over time compared with conventional formulations. - In lab tests and controlled skin applications, the tetrapod sunscreens reflected visible light differently and appeared warmer on skin without added coatings or pigments; researchers are working with UCLA Health dermatology, including the Skin of Color Clinic, to study skin microbiome interactions and further testing. Summary: The study suggests that altering zinc oxide particle shape can reduce the visible white cast that discourages some people from using mineral sunscreen, while maintaining comparable SPF and improved formulation stability. Researchers plan further testing and clinical study with dermatology collaborators to better understand skin interactions and move the approach closer to real-world use.