Safety and Efficacy of Melatonin in Patients With Multiple Progressive Primary Sclerosis

Inclusion Criteria: Patients who come to the Multiple Sclerosis Unit of the Department of Neurology of the Virgen Macarena University Hospital (Seville) or Vithas Nisa Seville Hospital or Virgen del Rocío University Hospital (Seville), and who meet the following criteria: * Have progressive primary multiple sclerosis according to McDonald's diagnostic criteria modified in 2010. * Age between 18 and 65 years old. * Neurological impairment measured with the Expanded Disability Status Scale (EDSS) scale between 2 and 7 (both included, without disability or only clinical symptoms up to ambulatory capacity with bilateral support). * Not having received any immunomodulatory, except for ocrelizumab in stable doses for at least 9 months before inclusion in this study, or immunosuppressive treatment (including cytostatic agents) during the 3 months prior to participation in the trial. * If there is a possibility of pregnancy (in women of childbearing age (15 to 44 years)) or paternity, accept the use of a highly effective method of birth control recommended by the Clinical Trial Facilitation Group (CTFG) during the treatment phase of the trial.. * Not having consumed melatonin or other dietary supplements (antioxidants or vitamins (tripling the recommended daily doses) during the month prior to participation in the trial. * Ability to give informed consent and comply with the visits scheduled in the study. Exclusion Criteria: * Alternative diagnosis that explains both the neurolog…