Fibromyalgia is a chronic pain disorder characterized by widespread musculoskeletal pain, fatigue, and sleep disturbances, significantly impacting patients' quality of life. Melatonin, a hormone known for regulating sleep-wake cycles, has been proposed as a potential therapeutic option for managing fibromyalgia symptoms.

We conducted a systematic search in PubMed, Embase, Scopus, and the Cochrane Library for randomized controlled trials, observational studies, case studies, and abstracts that used melatonin as a treatment for patients diagnosed with fibromyalgia. Data regarding pain, sleep quality, depression, fatigue, anxiety, and stiffness were extracted and analyzed in accordance with PRISMA guidelines, with each outcome measured using various validated scales.

After screening 852 results, 6 studies comprising 151 patients, the majority of whom were female, were included. The outcomes were measured using various scales, including the Numeric Pain Scale (NPS) for pain, Health-Related Quality of Life (HRQOL) and Fibromyalgia Impact Questionnaire (FIQ) for quality of life, the Visual Analog Scale (VAS) for general well-being, Pittsburgh Sleep Quality Index (PSQI) for sleep quality, and the State-Trait Anxiety Inventory (STAI) for anxiety. The use of melatonin resulted in significant improvements across all these scales, enhancing quality of life, social interactions, mood, and overall well-being

Melatonin demonstrated significant therapeutic benefits in the management of fibromyalgia, leading to improvements in pain, sleep quality, anxiety, and overall quality of life. Given its favourable safety profile, melatonin may be a promising adjunctive treatment option for fibromyalgia, though larger, well-controlled trials are needed to confirm these findings.