Physical versus chemical sunscreens

You may have seen controversial articles in recent magazines regarding the safety of sunscreens. Some beach resorts have promoted limited sunscreen use due to its effects on undersea coral. Other concerns regard sunscreen absorption through the skin and its potential hormonal side effects.

There are two types of sunscreens: Physical (mechanical blockers) and chemical (skin filters).

The mechanical blockers are zinc oxide and titanium dioxide. They sit on top of the skin and block all harmful skin rays. They are made from natural minerals that are non-allergenic and not harmful to you or the environment. On the other hand, even in the most elegant formulations, they are visible (though they don’t have to be neon colors!).

Due to the visibility of the physical sunscreens, other chemicals, which filter out (absorb) sun rays were developed and created a new category of chemical sunscreens. The most common are: oxybenzone, avonbenzone, octisalate, octocrylene, homosalate and octinoxate. These chemicals are absorbed into the skin, so they don’t show or wash off easily, but they have downsides. First, they don’t always block all the types of harmful rays (UVA, UVB and UVC). Second, they are more likely to be allergenic. And finally, there is insufficient evidence on the significance of systemic absorption, the most concerning of these chemicals being oxybenzone.

In 1972, the FDA thoroughly evaluated sunscreens for “generally recognized as safe and effective” (GRASE). Since then, there have been new chemicals and new toxicity studies. In February 2019, the FDA issued a request for updated research on absorption and toxicity from the sunscreen manufacturers. The data was submitted in May 2019 and the FDA is expected to render a report in November of 2019.

So what types of sunscreen should you use until the report findings are publicized? 

The vast majority of sunscreens we offer at Surface Clinical are of the physical category and contain zinc oxide and titanium dioxide. These include Alastin, Colorscience, ZO Skin Health, and most of the Elta products. The only products we offer with a chemical filter are Elta Clear 46, Elta Aero, Elta Daily, Elta Daily Tinted, and Elta Sport. The latter products contain octinoxate in an FDA approved 7.5% concentration.

Don’t let the uproar discourage your use of sunscreens! Sunscreens reduce the incidence of skin cancer by 40% and melanoma by 50%. The key here being application and re-application throughout the day.

In summary, just because something is slightly absorbed doesn’t necessarily mean it is enough to be harmful. But it is appropriate for the FDA to be sure of safety, hence the need for a new, updated report. We will keep you posted.

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