In Vivo Human Hair Hydration Measurements by Using Opto-Thermal Radiometry

© 2019, The Author(s). The water content in human hair is very important for its cosmetic properties and general health. However, to measure water content in hair, especially in vivo hair, is very difficult. Opto-thermal transient emission radiometry (OTTER) is a promising, infrared remote sensing technology that can be used for this kind of measurements. It can not only measure the water content but also the water depth profile in hair. By measuring the water content and its depth profile in hair, we can understand the status of hair, i.e., healthy or damaged, etc. In this paper, we will present our latest study on in vivo human hair hydration measurements by using OTTER. We will first present the theoretical background and then show the experimental results. We will also compare the OTTER hair results with other established measurement technique results, such as condenser trans-epidermal water loss method.