In pursuit of early detection methods to reveal invisible photodamage in skin, Kao Corp. scientists explored biophoton emissions from the human body. They found that increased emissions, induced by UV exposure, correlated with skin dehydration and increased roughness parameters.
Kao Corp.'s skin care, analytical science and biological science research divisions built the present study upon a method its biological division developed in June 2019 for the early detection of biophoton emissions—"ultra" weak photons emitted by the human body. The goal was to find new ways to prevent signs of photoaging.
In the earlier work, using an advanced photon detector, the team measured changes in biophotons after UV exposure. They noted biophotons related to lipid peroxides were emitted for as long as 1 to 3 min after exposure, and that lasting emissions strongly correlated with skin redness/erythema.
Applying this technique, the present study linked decreases in skin's water content and increases in its surface roughness to oxidative damage—represented by higher biophoton emissions measured 1 to 3 min after UV exposure. These changes in skin also were related to a history of chronic sun exposure.
Taken together, these results indicate that chronic UV damage can lead to photoaging via an early skin deterioration process, resulting in skin dehydration and accompanied by surface roughness. The company presented these findings at the 49th Annual Meeting of the European Society of Dermatology Research, held in Bordeaux, France, Sept. 18 to 21, 2019.