Mapping the Moisture in your Skin

Water plays a key role in allowing the stratum corneum, the outermost layer of the skin, to act as a protective barrier against the environment. Keeping skin supple and achieving ideal water concentration in this layer is vital to overall skin moisture.

In order to understand the depth of moisture deep in the skin, P&G Beauty scientists have applied a new method called Confocal Raman Microspectroscopy (CRM) that actually maps the molecular concentration of water in the stratum corneum. 

In Raman spectroscopy a substance is illuminated with specific wavelengths of light.  Light inelastically scattered by the sample contains information about its chemical makeup.  Using a variably focused laser light source and appropriate detection, this technique was combined with confocal microscopy, an optical imaging technology used to reconstruct three dimensional images, to generate non-invasive, chemically specific "depth profiles" also known as molecular maps of the living skin.

Most recently, P&G Beauty scientists utilized CRM to compare the effect of different moisturizers on human skin by measuring the relative depths of the stratum corneum and water content of skin treated with different moisturizers.  A greater depth of stratum corneum indicates a healthier barrier function, which leads to superior skin hydration.  This has provided valuable insight into the efficacy of moisturizing formulas. 

Specifically, in a study presented at The American Academy of Dermatology (Matts, 2006), P&G Beauty scientists used this technique to determine that moisturizers containing niacinamide were effective in both increasing the stratum corneum thickness, and thus barrier efficiency, as well as increasing water concentration gradient in the stratum corneum.