Fibromyalgia syndrome (FMS) is a chronic disorder characterised by widespread musculoskeletal pain, troubled sleep, disturbed mood, and fatigue. Recently published reviews have demonstrated that it is influenced by various psychological aspects, and antidepressants are now considered the treatment of choice for most patients. The aim of this randomised controlled trial was to compare the effects of duloxetine and acetyl L-carnitine on pain, depression, anxiety and well-being in FMS patients.