Differential thermal analysis of human sebum as a new approach to rheological behaviour

Synopsis The oily aspect of a hair is not only the consequence of an excessive lipidic production on the scalp; the quality of the fatty mixture should also be considered. Differential scanning calorimetry (DSC) is a useful tool for qualitative examination of human sebum. The melting curves recorded using this technique characterise the seborrhoeic state of the subject, their profile being related to the clinical appreciation. Data from DSC are correlated with other physico-chemical characteristics of sebum, especially with the proportion of unsaturated fatty acids in the whole fatty acids fraction. The straight chain monoenic acids have been more closely examined. A number of positional isomers can be seen; the distribution of the C(18) isomers varies according to the seborrhoeic state of the subject.