Melatonin and Zinc Administration on Cardinal Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic Encephalomyelitis, also known as Chronic Fatigue Syndrome (ME/CFS) is a heterogeneous condition characterized mainly by debilitating and prolonged fatigue, post-exertional malaise (physical, mental and emotional), unrefreshing sleep, cognitive impairment, and orthostatic intolerance with prolonged recovery that is not relieved by rest. Currently, the etiopathogenic mechanisms of ME/CFS are unknown. At present, there is no diagnostic test or effective treatment. MelatoZinc is a food supplement composed of melatonin and zinc, which could contribute to the circadian rhythm homeostasis and regulation of redox imbalance and immune response. The aim is to evaluate the efficacy and safety of oral treatment with MelatoZinc on the symptomatic complex of fatigue in a larger Spanish ME/CFS population. This is a single-center, randomized, double-blind, placebo controlled clinical trial. It will include a total of 106 ME/CFS patients who met 2011 ICC criteria for ME/CFS. All patients will take one capsule daily for 16 weeks. Group A will receive MelatoZinc (1 mg melatonin plus 10 mg zinc), and group B will receive a placebo (excipients: isomaltose and magnesium stearate). Clinical symptoms will be evaluated, and standardized questionnaires will be applied to assess the impact of fatigue, pain, anxiety-depression symptoms, sleep quality, dysautonomia, and quality of life. Heart rate variability (HRV) and orthostatic intolerance (10-min NASA Lean Test) will be performed to evaluate autonomic dysfunction. Sleep efficiency will be estimated through an actigraph sensor