Protein–water interactions establish and shape the thermodynamic landscape that governs the folding, structure, stability, mechanics and activity of proteins, and thus performance of protein based materials such as skin and hair. In tissue or cellular based protein material systems such as human hair the mechanical and physical performance of these materials in humid environments is very complex and is poorly understood.In this study a series of keratin based fibres, including hairs of different ethinicitiies, will be studied at different humidities and temperatures using neutron scattering. This work will allow us to better understand the way water diffuses in these complex materials at different temperatures and humidiies. This improved understanding of the hydration behaviour of hair may facilitate the development of improved products for hair care.