Evaluation of the Effectiveness of Protective Lipsticks with Different Sun Protection Factor Values Against UVA and Infrared Radiation

Sunlight contains a wide spectrum of radiation from ultraviolet (UV) through visible light to infrared (IR). UV radiation plays a crucial role in skin damage, photoaging, and carcinogenesis, necessitating effective photoprotection strategies. The study evaluated the efficacy of protective lipsticks with different sun protection factor (SPF) values (10, 15, and 30) against UVA and infrared (IR) radiation. In this study, the directional-hemispherical reflectance (DHR) was measured across various spectral bands (335–380 nm, 400–540 nm, 700–1100 nm, and 1000–1700 nm) with SOC 410 Reflectometer (San Diego, CA, USA). Since the device used in this study did not cover the UVB range (290–320 nm), this study does not provide a direct assessment of SPF in its conventional sense. The measurements were taken at four time points up to 120 min after lipstick application. Results indicated that lipsticks with higher SPF values significantly altered skin reflectance in UVA and IR ranges, with SPF30 showing the lowest reflectance in the UVA range (335–380 nm), suggesting greater absorption of UVA radiation by the product and significantly higher reflectance in IR ranges compared to lower SPF lipsticks. Reflectance values generally increased over time post-application for key spectral bands. These findings demonstrate that SPF lipsticks provide variable attenuation of UVA and IR radiation, highlighting their role in comprehensive lip photoprotection. The data support the importance of SPF selection for optimized protection, especially against penetrating UVA and IR components of sunlight.