The open skin and hair are directly endangered by UV radiation which is the strongest external source of free radicals (FR). In both cases it is the natural pigment melanin, which protects human skin and hair from FR, by its scavenger reaction: melanin eliminates the UV radiation but finally it changes into FR too. The amount and also the function of melanin depend on the function of melanocytes. In case of hair illness the disruption occurs of cycles of melanogenesis,whichis tightcoupling to the hairgrowcycle.Wewerefocusing our interest to discover possible connection of this process with the amplitude of FR signal. Eight samples of human hairs, from seven women and from one man, all the patients of dermatological clinic were delaminated by the optimal method for identification and estimation of FR, which is the electron paramagnetic resonation spectroscopy (EPR). We used the Spectrometer Bruker Elexsys E-540 (Bruker-Biospin, Rheinsteten, SRN); the magnetic field was measured by 1H-NMR magnetometer. EPR signals were recorded as the first derivation of the absorption spectrum. For evaluation and identification of signals the computer programmes Origin, WINEPR (Bruker, Rheinsteten, Germany) were used as well as the Internet base from NIEHS, (Bethesda, Maryland, USA). The common reagents were used for the analysis, redestilated water and the standards for the spectral calibration from Galenus GmbH, (Berlin, Germany). The resulted spectrum pictures of FR are closely linked with the patients’ diagnosis and with the amplitude and kind of FR signal.

        Key words: hairs, free radicals, EPR, melanin, Fe3+ Mn2+.