A new study between the University of Leeds, the University of Oregon and Oregon State University is shedding some UV light on the go-to SPF ingredient of zinc oxide and how it reacts to other ingredients—and it’s making for some interesting observations surrounding the mineral.
“On its own, zinc oxide is an effective and harmless UV blocker,” Richard Blackburn, Professor of Sustainable Materials at Leeds’ School of Design, said in a statement. “Our research raises concerns about how the individual formulation ingredients react with each other during use and this isn’t currently tested by the industry. Once exposed to sunlight for two hours, zinc oxide destroys the UVA protection provided by other ingredients. In this context, putting on sunscreen could actually make things worse because people believe they are being protected from harmful UV rays and may stay in the sun longer.”
During the testing, the research teams found that “the UVA protection factor was reduced by between 84.3 percent and 91.8 percent in the sunscreen mixed with zinc oxide particles, while the original sunscreen without zinc oxide only showed a 15.8 percent loss in UVA protection factor, after UV exposure for two hours.”
“This is an interesting study and it does underline the importance to evaluate the interaction of various ingredients in skin care products, including sunscreens,” says Davie, FL dermatologist Marianna Blyumin-Karasik, MD. “Their interaction may result in decreased efficacy, as well as potential irritating reactions.”
But, Dr. Blyumin-Karasik stresses, pure zinc oxide sunscreens are still considered the safest, organic, clean and water-resistant as well as broad-spectrum coverage in appropriate formulations. “They are also safer for our environment. However, like any other sunscreen, they do not last longer than an hour-and-a-half. So frequent reapplication and applying a generous amount during sun-exposure activities is what we advocate as dermatologists.”
“As everyone knows, to a dermatologist, sunscreen is life, and I never leave home without it,” says Saddle Brook, NJ dermatologist Dr. Fredric Haberman, who refers to ISDIN Eryfotona Actinica as his current “life-saving” sunscreen.
And, even in light of this latest study, Dr. Haberman stresses that the evidence supporting safety in sunscreen is very reassuring. “Scientific studies support wearing sunscreen on a regular basis to protect against skin cancer. Sunscreen ingredients have been used in the United States safely for many years.”
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