UCLA cuts sunscreen's white cast with tetrapod zinc oxide
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- UCLA Health Jonsson Comprehensive Cancer Center researchers led by senior author Paul S. Weiss reshaped zinc oxide into microscopic four-armed "tetrapod" particles via a patented high-temperature flame process to address the chalky residue common in mineral sunscreens.
- The tetrapod formula reached SPF 30 at the same concentration as conventional zinc oxide nanoparticles, remained more stable over time, and reduced the white cast without added pigments or specialized coatings.
- First author AJ Addae, a UCLA chemical biology doctoral candidate, said the project started with his own frustration over how mineral sunscreen looks on his skin — a problem that had driven him to skip sunscreen altogether.
- The tetrapod particles form porous networks with built-in standoffs that prevent them from collapsing into clumps, producing a warmer, more even appearance on skin in lab tests and controlled skin applications.
- Researchers note that people with darker skin tones are considerably more likely to die from melanoma because it is often diagnosed at a later stage, making a cosmetically acceptable mineral sunscreen a potential public health gain.
- Findings were published in ACS Materials Letters; commercial availability will require additional testing, and the team is collaborating with UCLA Health's Skin of Color Clinic to study how tetrapods interact with the skin microbiome.
Why it matters: The chalky residue from zinc oxide is a documented cosmetic barrier that disproportionately discourages sunscreen use among darker-skinned patients — a group that research shows is considerably more likely to die from melanoma because diagnoses come at later stages. By redesigning zinc oxide's physical structure rather than its chemistry, the UCLA team preserved SPF 30 while structurally preventing the clumping that scatters visible light, opening a path to daily-use compliance that existing mineral formulas have failed to deliver.
