Abstract: A method of gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous identification and quantification of five endogenous anabolic steroids (testosterone, epitestosterone, androsterone, etiocholanolone, dehydroepiandrosterone) in hair. After alkaline hydrolysis, the hair sample was extracted with diethyl ether, derivatized with a derivatization reagent (N-methyl-N-trimethylsilyl-trifluoroacetamid/iodotrimethyisilane/DL-dithiothreitol, 1000∶5∶5, v/v/w) and detected using GC-MS/MS in the multiple-reaction monitoring mode. The one precursor/two product ion transitions for each anabolic steroids were monitored. The limits of detection for five endogenous anabolic steroids were in the range of 0.1-0.2 pg/mg. All analytes showed good linearity and the extraction recoveries were 74.6%-104.5%. The inter-day and intra-day relative standard deviations （RSD） were less than 17.5%. This method has been applied to the analysis of testosterone, epitestosterone, androsterone, etiocholanolone, dehydroepiandrosterone in 80 Chinese hair samples. These data are the suitable references and the basis for the interpretation of the results from endogenous steroids abuse.

Key words: endogenous steroids, hair , gas chromatography-tandem mass spectrometry （GC-MS/MS）