Scanning electron microscopy, inductively coupled plasma mass spectroscopy and time-of-flight secondary ion mass spectrometry have been used to examine the extent and possible mechanisms by which the metal content of human hair is altered by exposure to aqueous environments. The results, using both modern hair and samples from 500-year-old hair associated with glacier-entombed remains, show that the metal content has been altered sufficiently so that the interpretation of the metal signature in terms of diet or disease is problematic. While endogenous information is difficult to glean from these data, interesting observations have been made of possible early stages of mineral authigenic deposition. The chemistry of the outer hair surface was found to be consistent with deposition of Fe and Al silicates, as well as other mineral phases. The ancient hair was analysed at the root region and included a comparison of the internal versus external composition to assist in identifying the diagenetic processes.