In vitro and clinical evaluation of a multifunctional sunscreen emulsion as an intervention for UVA-induced...

Chronic UVA exposure leads to oxidative stress, extracellular matrix degradation and DNA photodamage, resulting in clinical manifestations of photoaging. In addition to UV filtering, multifunctional sunscreens enriched with antioxidants and humectants may support skin barrier repair and inflammation mitigation.

To evaluate efficacy against UVA-induced photoaging by assessing (i) post-UVA reparative effects in a 3D skin model and (ii) the clinical effect of once-daily use over 28 days in Chinese women.

A 3D full-thickness human skin model was exposed to UVA (35 J/cm²) as a single-challenge stressor and then treated with the sunscreen emulsion to assess residual CPD levels measured post-irradiation, epidermal thickness, fibroblast density and collagen remodelling. In parallel, a 28-day clinical study in 63 Chinese women assessed hydration, TEWL, elasticity, redness and dermatologist-graded signs of aging following once-daily facial application.

In vitro, when applied after UVA exposure, the formulation reduced residual CPD levels measured post-irradiation (-68.1%), restored epidermal thickness (+109.7%) and fibroblast density (+131.1%), and upregulated collagen types I, IV, VII and XVII. Clinically, the emulsion improved hydration (+33.7%), reduced TEWL (-15.6%), increased elasticity (+14.0%) and attenuated facial redness (-73.7%). Dermatologist grading confirmed significant improvements in wrinkles, firmness and tone evenness.

This dual-model evaluation demonstrates that the multifunctional sunscreen emulsion not only provides broad-spectrum photoprotection but also supports structural repair and barrier function in UVA-compromised skin. These findings support its potential as an integrated solution for photoprotection and anti-photoaging care in Asian populations.