It’s the lack of enzymes essential for moisturizing!

The outermost layer of the skin is visible and touchable. This outer layer is called the epidermis and is further divided into four layers. Of these layers, the outermost layer is called the stratum corneum. The role of the stratum corneum is to protect the skin from external dry air, ultraviolet light and bacteria, and to prevent escape of moisture from the body. Thus, the stratum corneum has a barrier function both for outside and inside of the skin.
Natural moisturizing factor NMF is responsible for maintaining moisture in the stratum corneum. This is an important factor both for the moisture in the skin and the barrier function. Insufficiency of NMF causes the barrier disruption, leading to skin dryness and roughness.

NMF is generated from a substance called filaggrin; however, this study was the first to clarify the mechanism of NMF generation. The key to NMF production was found to be an enzyme called BH, which is able to degrade filaggrin to produce NMF. BH is decreased by various factors such as aging; however, people with dry skin, sensitive skin, and skin diseases such as atopic dermatitis have extremely low levels of BH compared to people with healthy skin. Low levels of BH resulted in the inability to create NMF from filaggrin, thereby causing deterioration of the barrier function.

The scope of the award only covers the mechanism of NMF production. However, after winning the IFSCC award our research continued and has led to the discovery of components that facilitate the manifestation of BH. These findings have already been applied in the aging care “d program” for SHISEIDO IBUKI, which is marketed overseas. Also, this award attracted attention from medical societies due to the first mention of the relationship between NMF and atopic dermatitis.

Nowadays, we are exposed to dry air from air conditioners in summer and heaters in winter, hence more and more people develop dry or sensitive skin. The findings of this research elucidated only a part of the mechanism that leads to sensitivity and roughness of the skin, and Shiseido will continue further research in this field.