Shiseido Develops Technology to Evaluate Subsurface Scattering Light*1 Within Skin “Based on Penetration Depth,” Advancing Skin Transparency Research

In pursuit of achieving skin translucency, Shiseido's optical research is focusing on how light incident on the skin penetrates the stratum corneum, reaches the dermis, and again exits the skin's surface (subsurface scattering light*1), namely, the behavior of light on the skin. The company is advancing research by developing the world's first optical measurement system*2 capable of non-invasively measuring and analyzing three-dimensional facial shape and optical conditions.

This time, through joint research with the Muroran Institute of Technology, Shiseido has further advanced its optical measurement system and developed technology to evaluate the behavior of light at different penetration depths within the skin. Measurement and analysis results revealed that short-wavelength light (blue) reaches the epidermis, mid-wavelength light (green) reaches the area from the epidermis-centered around the basement membrane-to near the upper dermis, and long-wavelength light (red) reaches the collagen layer of the dermis before it is re-emitted from the skin's surface (Figure 1).
Furthermore, as short-wavelength light (blue) reaches the epidermal layer, non-invasive measurement and analysis of the relationship between melanin level and light reaching and emitted from the epidermal layer revealed that melanin is significantly involved in light absorption. Melanin blocks light, making it difficult to penetrate the skin, thereby reducing the amount of light emitted from the skin's surface. Additionally, as long-wavelength light (red) penetrates the dermal collagen layer, Shiseido applied the internal and external skin elasticity 3D imaging system*3 that visualizes both inside and outside the skin and enables non-invasive observation of collagen status in living human skin, to evaluate collagen fiber density*4 and analyze correlation. The results revealed that reduced collagen density decreases the amount of light reaching the dermis and emitted from the skin's surface (Figure 2).

These findings demonstrate that melanin levels in the stratum corneum and the epidermis, along with dermal collagen density, are essential for achieving skin translucency. Shiseido will continue advancing optical control technologies to realize beautiful skin and will apply these insights to develop new solutions.

Part of the results of this research was published as an academic paper in "Optical Review, 31(2), 261-279" and was also presented at the "European Conference on Biomedical Optics (July 2025)" and "Optics Photonics Japan (December 2025).

*1 Light that penetrates the skin, undergoes absorption and scattering, and is ultimately emitted from the skin's surface. Also known as subsurface scattering light
*2 Shiseido Develops World's First Measurement System for Three-Dimensional Shape and Subsurface Scattering Light in Facial Skin (2022)
https://corp.shiseido.com/en/newsimg/3538_o8e53_en.pdf
*3 Patented technology that converts ultrasonic reflected signals from within the skin into elastic modulus, developed through joint research with Honda Electronics Co., Ltd. and Toyohashi University of Technology
*4 Shiseido Wins First Prize for Digital Poster Presentation at the Asian Societies of Cosmetic Scientists Conference 2024 in Goa (2024)
https://corp.shiseido.com/en/newsimg/3818_e8q86_en.pdf