UCLA researchers have developed a new mineral sunscreen formulation designed to reduce the white, chalky appearance often left by traditional products containing zinc oxide. The research, led by the UCLA Health Jonsson Comprehensive Cancer Center, found that changing the shape of zinc oxide particles could help address one of the main cosmetic issues that discourage daily sunscreen use.
Mineral sunscreens are recommended for people with sensitive or acne-prone skin and are classified as safe and effective by the U.S. Food and Drug Administration. However, many Americans avoid using them because they tend to leave a noticeable white cast on the skin, especially among those with darker skin tones.
The study explored whether altering the physical structure of zinc oxide particles would make a difference. Most commercial sunscreens use round nanoparticles of zinc oxide, which can clump together and scatter visible light, resulting in a white or gray tint. The UCLA team tested an alternative: larger particles shaped like microscopic four-armed tetrapods produced through a patented high-temperature flame process.
“Because of their structure, these tetrapod-shaped particles have standoffs and form porous networks instead of collapsing into clumps,” said AJ Addae, a UCLA chemical biology doctoral candidate and first author of the study. “They can’t pack tightly and aggregate, so they stay evenly distributed in the sunscreen.”
Tested at equal concentrations to conventional formulations, sunscreens made with tetrapod-shaped zinc oxide achieved an SPF of about 30—comparable to standard products—and remained stable over time without separating or thickening. Laboratory tests showed that these new formulations reflected light in a way that appeared warmer and closer to natural skin tones without added pigments or coatings.
“When I spread it on my own skin, I didn’t get that white cast I usually see with zinc oxide,” said Addae. “That was the moment I realized this could really work.”
Senior author Paul S. Weiss explained: “This isn’t just about cosmetics. If improving how sunscreen looks leads to more consistent use, it could have real implications for skin cancer prevention.” He noted that encouraging broader use across different skin tones may be particularly important for those who are less likely to use sunscreen regularly and face later-stage diagnoses if they develop melanoma.
Other contributors included Jennifer Uyanga; Justin Carman (Addae’s thesis co-advisor); both from UCLA chemistry; and Yogendra Kumar Mishra from University of Southern Denmark. Funding came from sources including the National Science Foundation.
The team is collaborating with UCLA Health’s department of dermatology—including its Skin of Color Clinic—to further investigate how these particles interact with the skin microbiome before potential commercialization.
“The best sunscreen is the one people will actually use,” Addae said. “If zinc oxide can be made to look better on more skin tones without sacrificing protection, it could help more people protect themselves from the sun’s most dangerous effects.”
