AJ Addae, an innovative scientist and cosmetic entrepreneur who studies chemical biology at UCLA, took a hands-on approach to tackling this problem.
"They leave this white cast on my skin, and it deters me from wanting to use sunscreens," Addae said.
It's an issue people with dark skin have dealt with since zinc oxide sunscreens have been around. Addae knew there had to be an elegant solution.
"The best sunscreen is one that you'll wear, and that's really all where my motivation is for this," she said.
She teamed up with her professor Dr. Paul S. Weiss with the UCLA Jonsson Comprehensive Cancer Center to understand the problem.
"We took apart conventional sunscreens that use zinc oxide and learned that the white cast comes from agglomeration of these round, somewhat irregular particles of zinc oxide," he said.
The round particles cause the clumping. So what would happen if they could make zinc oxide in a different shape?
"The tetrapods have these legs on them that make them stand apart," Weiss said.
They collaborated with a University of Denmark researcher who had done previous work with tetrapods.
"It forms these networks, really nice, sustained networks of zinc oxide that disperse really well and smoothly and evenly on the skin," Addae said.
But would it protect skin as well as its round, clumpy counterpart?
In their American Chemical Society paper, they proved it did.
"We were happy to see that it did absorb really similarly to other zinc oxide types that are on the market," she said.
Not only was it effective, Addae said tetrapod zinc oxide requires no solvent, making it a greener option.
Scientists said the Food and Drug Administration hasn't approved a new UV filter since 1999 so getting a new type sunscreen passed regulators is difficult. This product would already be approved for use.
While chemical sunscreens are available, Addae says many consumers, like herself, prefer zinc oxide.
"I think it's going to be a good step in the right direction for getting everyone to wear sunscreen and prevent skin cancer," she said.
She's working with UCLA to bring the product to market.