Bisher AKIL, MD

The Sunscreen in your blood

In Uncategorized on January 23, 2020 at 6:16 pm

Chemical sunscreen ingredients are systemically absorbed after one application, and some ingredients can stay in the blood for at least 3 weeks, according to an FDA study published in JAMA.

In a lab setting, 48 adults were randomized to receive one of four formulations of chemical sunscreens containing avobenzone (in most sunscreen products) , oxybenzone, octocrylene, homosalate, octisalate, or octinoxate. Sunscreen was applied once on the first day and four times on days 2 through 4. Participants had 34 blood samples collected over 21 days.

The maximum plasma concentration of avobenzone over days 1 through 21 — the primary outcome — was 7.1 ng/mL for lotion, 3.5 ng/mL for aerosol and nonaerosol spray, and 3.3 ng/mL for pump spray. For all six active ingredients, most participants had maximum plasma concentrations that were at or above the FDA’s 0.5 ng/mL threshold (for possibly waiving additional safety studies) for as long as 23 hours after a single application. For homosalate and oxybenzone, over half of participants had above-threshold plasma levels 21 days after application.

The authors say their findings reinforce the need for further studies on sunscreen safety. Editorialists conclude: “In the absence of clear data demonstrating harm, the use of chemical sunscreen may still be considered appropriate; the use of mineral-based sunscreen is a well-established safe alternative.”

Source; Reported NEJM Journal watch, Juanary 22,2020

Link:  Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active IngredientsA Randomized Clinical Trial; Murali K. Matta, et al; JAMA. 2020;323(3):256-267. doi:10.1001/jama.2019.20747


Comments: Sunscreen, also known as sunblock, is a lotion, spray, gel, foam, stick or other topical product that absorbs or reflects some of the sun’s ultraviolet (UV) radiation and thus helps protect against sunburn. Diligent use of sunscreen can also slow or temporarily prevent the development of wrinkles, dark spots and sagging skin. Depending on the mode of action, sunscreens can be classified into physical sunscreens (i.e., zinc oxide and titanium dioxide, which stay on the surface of the skin and mainly deflect the sunlight) or chemical sunscreens (i.e., UV organic filters, which absorb the UV light). This study emphasizes the preference to using mineral-based sunscreens- BA

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