Quite recently an "amazing new sunscreen" formula was approved for sale in the United States - it contains mexoryl, otherwise known as ecamsule. It was touted as the miracle sunscreen with "incredible" UVA absorption, and people decried its prior absence from US markets as governmental conspiracy.
This KLRC article debunks the exaggerated hype about this compound based on data published by L'Oreal - the very company that owns exclusive rights to mexoryl's use in sunscreens.
Mexoryl has been touted by the popular media and various high profile dermatologists as "the" new sunscreen - some interviewed have called it "almost perfect." Incidentally, the person most quoted is Dr. Darrell Rigel, NYU Dermatology (and advisor to L'Oreal; judge for yourself if a conflict of interest exists.).
In light of Anthelios SX 's acquisition of FDA approval, KLRC did its own evaluation based not on an agency conflicted 'authority' opinion, but the science at hand. Amazingly, it found a paper published in Photochemistry and Photobiology in 2000 by scientists at L'Oreal comparing mexoryl's UVA absorption to that of ethylhexylmethoxycinnamate, another popular petrochemical sunscreen active ingredient, and long known as mostly a UVB absorber. You can read this paper here, but the results are summarized by the graphic above with the zinc oxide absorption curve superimposed for comparison.
Mexoryl may be the perfect sunscreen in a dermatologist's dreamworld where L'Oreal's financial compensation enables him to retire and live on a yacht, but the facts suggest otherwise. First, even the now-ancient avobenzone (trade-named Parsol 1789)'s UVA absorption spectrum is actually broader than mexoryl's - it absorbs more like zinc oxide above 380nm. Second, while mexoryl is supposed to be more UV-stable than other sunscreens, sunscreens must be reapplied because they disappear from the skin (due to sweat, water, towels, other contact, etc.) at least every two hours to be effective. Period. The level of stability isn't publicized for comparison, either, so what exactly does 'more stable' mean, five seconds more stable? It's certainly not earth- shattering stability data or it'd be explicitly available. Third, mexoryl is a di-sulphonic acid compound with a native pH of 1 (more acidic than your stomach) and needs to be neutralized with a base (triethanolamine is generally used - it's the subject of another KLRC article). Fourth, formulas that use mexoryl must also have additional UVB absorbers to provide protection in that part of the UV spectrum, which result in additional petrochemical exposure. Finally, compared to zinc oxide, mexoryl is simply an inferior sunscreen active ingredient, from all perspectives - health, stability and spectral absorbance. That is scientific fact - you can check the data for youself.
KLRC finds it disappointing, but not surprising given the money at stake, that even the 'experts' refuse to recognize that the optimal sunscreen already exists. It is zinc oxide, the sole UV absorber Green Screen SPF 15 uses due to its health, stability and spectral absorbance profile.
Did we mention that Anthelios SX is about $40 for a 3.4 ounce tube?
Read our labels and you understand!(tm)
KLRC Next Month: Pregnant? What Mothers-To-Be Need To Know About Skin Care.
More sunscreen facts from the AAD
If link fails to work: http://www.aad.org/aad/Newsroom/factsunscreen.htm
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