Inclusion Criteria:  Patients were potentially eligible if they were female, aged 18 years or older, and had a confirmed diagnosis of ME/CFS by a specialist according to the 1994 CDC/Fukuda criteria  Exclusion Criteria:  Exclusion criteria were those with any significant active fatiguing medical disorder (thyroid-related disorders, sleep apnea, narcolepsy, medication side-effects, heart diseases, iron deficiency anemia), previous diagnosis not unequivocally resolved (chronic hepatitis, malignancy), autoimmune disorders, history of past/current neuropsychiatric disorders (major depressive disorder, psychotic or melancholic features, bipolar disorder, schizophrenia, delusional disorder, dementias, anorexia nervosa, and bulimia nervosa), and participation in another clinical trial of the same or different nature within 30 days prior to study inclusion; inability (in the opinion of the investigator) to follow the instructions or to complete the treatment satisfactorily; failure to provide signed informed consent; use of certain drugs and supplements that might influence outcome measures in the last 90 days or whose withdrawal might be a relevant problem, anticoagulant treatment, pregnancy or breast-feeding, smoking habits, alcohol intake or substance abuse, strong hormone-related medications, and obesity.