UVA1 rays (340–400 nm) account for at least 75% of ultraviolet wavelengths reaching the Earth. They are able to induce epidermal and dermal damage and contribute to immunosuppression, carcinogenesis, hyperpigmentation and photoaging 1-5. Today, state of the art sunscreen formulas can efficiently filter UV wavelengths up to 370/380 nm, but have limited absorption in the 370/380–400 nm wavelengths range. Recently, a new cyclic merocyanine UVA1 absorber, Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate (MCE -Mexoryl 400TM), exhibiting a maximal peak of absorption at 385 nm was approved by the SCSS for use in sunscreen products. Previous studies showed that formulations containing MCE enabled significantly higher UVA1 protection of the epidermis and the dermis, with a better protection against dermal fibroblasts alterations in vitro and anti-pigmentation efficacy in vivo under controlled UV exposure 6. These results demonstrated the great potential of extended UVA1 protection on skin damage prevention, however, until now, there was no evidence of the added benefits of efficiently covering the whole UV spectrum on skin photoaging face signals, in vivo, in real life conditions. Thus, the objective of this study was to evaluate in vivo global anti-aging benefits of a higher and broader UVA1 protection with the daily application of a sunscreen formulation enriched with MCE.
For this purpose, fifty-two healthy female volunteers, phototypes I-III, aged between 35-65 y.o. were enrolled in a double blind, split-face clinical study in Brazil. After 2 weeks of wash-out, a sunscreen enriched with MCE 1% (SPF 50+) with an absorption profile covering the longest UVA wavelengths, up to 400nm, and a reference state of the art sunscreen (SPF 50+ without MCE) were applied half-face twice daily with controlled application for one month. The volunteers were sun exposed for up to two hours daily and they had standard pictures acquisition and clinical aging signals evaluation using Skin Aging Atlas 7,8 at baseline and after one month.
The assessment by Skin Aging Atlas showed that MCE enriched sunscreen improved significantly crow's feet wrinkles (p<0.05), upper lip wrinkles (p<0.05), ptosis wrinkles (p<0.05), texture of the mouth contour (p<0.05), upper lip texture (p<0.05), whole face pigmentation (p<0.05) and vascular disorders (p<0.05) when compared to baseline and to the reference formula after one month. In addition, MCE sunscreen presented significantly better results vs the reference for other pigmentation signals: forehead pigmentation, lateral facial pigmentation and upper lip pigmentation (p<0.05).
In conclusion, the sunscreen containing MCE filter presented superior anti-aging benefits compared to a state-of-the-art broad spectrum sunscreen and improved skin aging signals. For the first time we prove that efficiently covering the whole UV spectrum thanks to MCE UV filter, we succeed to prevent and reduce skin photodamage signals in real life conditions.

References
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