Efficacy of a Dual‐Action
SPF
50+/
PA
++++ Sunscreen: A Multi‐Targeted Approach to Photoprotection and Skin Barrier Recovery
Jiamin Gu, Yue Ying Fu, Vanessa Koh, Hiroki Fujita, Jessica Wang, Sheila Ching Chua, Yuan Yuan Duan, Daiki Arai, Junchao Zhang, Mao Kasahara, Wei Lai ABSTRACT
Background
As sunscreens do not completely block ultraviolet radiation, chronic UVR exposure causes cumulative photodamage, increasing premature photoaging, and skin cancer risk. Hence, an optimal sunscreen should incorporate dual benefits, going beyond photoprotection while actively supporting skin barrier recovery post sun‐exposure.
Aim
To evaluate the broad‐spectrum photoprotective and barrier repair efficacy of a dual‐action sunscreen with Smart Layers Technology. Primary outcomes included photoprotection and barrier repair; secondary outcomes included pigmentation and skin tone improvement.
Methods
Photoprotection was evaluated in vivo, single center, evaluator blinded, self‐controlled study. Antioxidant activity was examined in an ex vivo human skin model under UVR‐induced oxidative stress. Barrier repair was studied in a randomized controlled trial and in vitro UVR‐induced epidermal barrier model, measuring filaggrin, loricrin, and claudin‐1. Pigmentation and skin tone were assessed in vivo UVR‐induced pigmentation model.
Results
The dual‐action sunscreen demonstrated high photoprotective efficacy, with a mean SPF of 56.2, UVA protection factor of 18.9, and 63.9% water resistance. Reactive oxygen species were reduced by 57.74%, demonstrating antioxidant effects. Post UVR‐irritated skin showed significant improvement in skin hydration and accelerated normalization of transepidermal water loss (both p < 0.001). Expression of key barrier proteins, filaggrin, loricrin, and claudin‐1, increased by 273.68%, 139.39%, and 167.57% respectively versus negative control. Skin brightness improved significantly (L*value; p < 0.001) with a significant reduction in pigmentation (a*value; p < 0.01) versus negative control. Skin melanin index and individual typology angle improved significantly ( p < 0.05) compared to negative control.
Conclusion
The dual‐action sunscreen addresses photodamage prevention and barrier recovery through broad‐spectrum photoprotection and UVR‐exposure skin barrier repair.