Hair fibres have no active renewable protective mechanisms yet hair (wool and fur) provides an essential protective function. Therefore, it is possible that hair contains a number of internal components to maintain fibre and protein structure and function through a range of normal environmental conditions. Trimethylglycine (betaine) provides cellular and protein protection during times of high osmotic stress and low water concentrations. These conditions are very pertinent to everyday cosmetic procedures such as shampooing, bleach or perming. Therefore, we have conducted preliminary investigations to establish the presence of natural betaine in hair as a possible ingredient to provide protection and maintain protein function. Using an high performance liquid chromatography (HPLC) technique designed for the analysis of betaine in blood and urine, we have demonstrated, via simple hot water extraction, a measurable level of betaine in blood and human hair. Further, we have demonstrated, in principle, the possibility of adding betaine back to the fibre via cosmetic products such as shampoos.