Although a popular European import with dermatologists and other skincare experts for years, LaRoche-Posay Anthelios SX ($29.00, SkincareLab.com) became available in the U.S. for the first time in 2007. From the official press release, “ANTHELIOS SX Daily Moisturizing Cream with SPF 15 is a revolutionary daily moisturizing cream containing Mexorylâ„¢ SX, a unique stable, organic sun filter that is highly protective against short wave UVA rays. It is the first time the FDA has approved a new sunscreen formula since 1988!” However, how does Anthelios SX Daily Moisturizing Cream with SPF 15 measure up to other sunscreens currently on the market?
Why Mexoryl?
Mexoryl, available as SX (water soluble) and XL (lipid soluble), is very effective for two reasons: one, it is very stable [as a benzylidene camphor derivative], and two, because it absorbs light at a broader range of UVA wavelengths than many other sunscreens. After absorbing light from this broad spectrum, ecamsule undergoes photoisomerization, followed by photoexcitation, which means that it causes for UV light to be released as thermal energy, rather than allowing for UV light to be absorbed into the skin. Additionally, Mexoryl SX and Mexoryl XL are even more stable than each alone; however, Mexoryl XL is often too oily for some with sensitive skin, and so only Mexoryl SX is featured in L’Oréal products sold in the U.S.
LaRoche-Posay Anthelios SX SPF 15 vs. L’Oréal Revitalift UV with Mexoryl SX
Winner: LaRoche-Posay Anthelios SX
Both LaRoche-Posay Anthelios SX and L’Oréal Revitalift UV with Mexoryl SX SPF 15 ($18.85, SaleAwaySavings.com) contain Mexoryl SX, the form of Mexoryl that is less oily than Mexoryl XL. However, compared with L’Oréal Revitalift UV, LaRoche-Posay Anthelios SX takes the prize, with 3% ecamsule (Mexoryl SX), compared with only 2% in L’Oréal Revitalift UV. Both contain identical amounts of additional sunscreens, including 2% avobenzone and 10% octocrylene.
LaRoche-Posay Anthelios SX SPF 15 vs. with Neutrogena SPF 30+ sunblocks
Winner: A tie
One method for measuring the UVA protection of a sunscreen is the PPD method, or Persistent Pigment Darkening method, as proposed in the journal Photodermatology, Photoimmunology and Photomedicine. By this method, LaRoche-Posay Anthelios SX reports in its brochure that it is the leading UVA blocker in the United States, and the “documentation is on file at LaRoche-Posay.”
A second method of measuring UVA protection is the PFA, or Protection Factor A, which is dependent on PPD. In essence, PFA is determined from the ratio of the sunscreen-protected minimal PPD to the unprotected PPD, evaluated 2 to 4 hours after UVA exposure. In comparing Mexoryl to Helioplex (found in Neutrogena sunscreens), Neutrogena Ultra Sheer SPF 70 has been reported to have a PFA value of 23.3 or 26.5, interestingly higher than the reported PFA value of 10 for Mexoryl SX and XL. Of course, these PFA values are not reliable. It would be helpful if the studies by LaRoche-Posay should release their aforementioned study, or, better yet, if an independent third party would conduct a study comparing the UVA protection of Mexoryl and Helioplex. Such a study was published in the Journal of the American Academy of Dermatology here in 2000; however, Mexoryl, which was not yet available in the U.S., was not included.
One other disturbing note: although the Anthelios SX website claims that “Mexoryl SX [is] the only FDA approved sun filter that fills the short UVA gap in sun protection in the US,” one must note the claim is not entirely valid. Helioplex combines avobenzone with stabilizing oxybenzone, which has an absorption maximum at 326 nm (as reported in Cosmetic Dermatology), completely within the short UVA range. By comparison, LaRoche-Posay Anthelios SX combines avobenzone with stabilizing ecamsule (Mexoryl SX), which has an absorption maximum at about 330 nm. Therefore, if you are buying this product to compensate for a “gap” in UVA radiation, you can save money with Neutrogena products.
Even supposing that LaRoche-Posay has the best UVA protection, I still call this one “a tie” because UVB is important to skin health as well, and LaRoche-Posay Anthelios SX only offers an SPF (a measure of UVB protection) of 15. Although UVA-induced damage includes the release of oxidative species, resulting in immunosuppression, photodermatoses, photoaging and photocarcinogenesis, UVB-induced damage includes inflammation and the release of oxidative species, and ultimately result in erythema, hyperplasia, hyperpigmentation, immunosuppression, photoaging and skin cancer, as reported in the Journal of Photochemistry and Photobiology. Therefore, UVB protection certainly is important, and Neutrogena sunscreens with good UVA protection in Helioplex also feature SPF up to 70. This is important, as, using an estimate from Dr. Rachel Herschenfeld, LaRoche-Posay Anthelios SX allows 1/15 UVB rays, or 6.6% through, while Neutrogena Dry Touch Ultra Sheer Sunblock SPF 70 allows 1/70 UVB rays, or 1.4% through. As such, even assuming LaRoche-Posay Anthelios SX does have somewhat superior UVA protection, Neutrogena sunblocks clearly can offer better UVB protection. So I call this one a tie.
In comparison with physical sunscreens (i.e., zinc oxide, titanium dioxide)
Winner: LaRoche-Posay Anthelios SX, unless you are sensitive to the product or are pregnant or nursing
It has been reported in Cosmetic Dermatology that micronized zinc oxide blocks UVA radiation effectively in the long UVA range, from 340 to 380 nm, while micronized titanium dioxide blocks UVB/short UVA radiation from 290 to 340 nm effectively. Clearly, from the graph above, LaRoche-Posay Anthelios SX is more effective than either physical sunscreen alone, and blocks in a similar range to zinc oxide and titanium dioxide in combination.
However, the avobenzone in LaRoche-Posay Anthelios SX may cause photoallergic contact dermatitis in sensitive individuals. In addition, although a 2005 study by Hayden et. al. clearly demonstrated that chemical sunscreens are not harmful when applied to the skin, avobenzone and oxybenzone have been demonstrated by Hayden et. al to be absorbed into the body and secreted into the urine of users. For this reason, it is a safe approach to use physical sunscreens rather than chemical sunscreens (avobenzone, oxybenzone) during pregnancy or while nursing and on small children. If you have doubts, ask your physician.
In summary…
A great product for UVA protection. I wish that more independent studies were done comparing its efficacy to that of other sunscreens, and that the UVB protection was significantly higher. At any rate, however, Mexoryl is a great UVA blocker and LaRoche-Posay Anthelios SX is certainly a first-rate UVA sunblock. I will post again when more studies become available, and when a product with Mexoryl and first-rate UVB protection arrives! 🙂