Assessing Protective Properties of Cosmetics with Directional Reflectance Measurements

The damage caused by Ultraviolet (UV) radiation on human skin is well documented in medical research and cosmetic companies have developed products to protect the skin.

The effects of Infrared radiation (IR) on skin is less clear but may include accelerated aging and increased severity of rosacea in people diagnosed with rosacea. The SOC 410 Directional Hemispherical Reflectometer was used (Wilczyński, et. al.) to determine the properties of 20 formulations applied to the skin of 36 volunteers. These formulations included 12 UV filters, 6 skin care creams of varying SPF, and 2 preparations containing fumed silica.

The SOC 410 was able to measure the reflected radiation from each subject’s arm covered with a test formulation. Directional reflectance measurements were taken of each subject’s skin surface three times for six spectral bands and two incident beam angles. The three times included before application of the formulation, 5 minutes after application, and 30 minutes after the product was applied. Potential IR protection can be indicated by any change in directional reflectance. An increase in reflectance would indicate reflected or scattered radiation. A decrease would indicate absorbed infrared radiation.

IR radiation penetrates and can damage all the skin layers. It had previously been reported that commercially available preparations could protect skin from IR. Those previous studies used skin samples and low aperture diameter of radiation emitters and were not reflective of real-life exposures. Using the SOC 410, this study was able to determine that commercially available products appeared to have very limited ability to protect skin for the breadth of the spectral band. The band of 4.0-5.0 μm was the most sensitive to UV filters and skin care creams, however, 4.0-5.0 μm is outside of the range of radiation emitted by the sun.

Based on the following published research
The Use of Directional Reflectance Measurement for in vivo Assessment of Protective Properties of Cosmetics in the Infrared Radiation Range. Sławomir Wilczyński, Anna Deda, Robert Koprowski, Anna Banyś, Barbara Błońska-Fajfrowska. doi: 10.1111/php.12786.

RESEARCH INSTITUTION
Medical University of Silesia in Katowice

AUTHORS
Sławomir Wilczyński, Anna Deda, Robert Koprowski, Anna Banyś,
Barbara Błońska-Fajfrowska

PRODUCT
SOC-410 Directional Hemispherical Reflectometer