Selenocysteine muscle pain ** **A lack of selenium cause muscle pain mechanism of action.** Selenium exerts its biological functions via molecules called selenoproteins which contain the amino acid cysteine with Role of Selenium Dependent Glutathione Peroxidases (Seleno GPxs) in Radio Modulation: Lessons for Radiation Oncology Biological Trace Element Research Springer Nature Link StructureActivity Correlation between Natural Glutathione Peroxidase (GPx) and Mimics: A Biomimetic Concept for the Design and Synthesis of More Efficient GPx Mimics Mugesh 2001 Chemistry A European Journal Wiley Online Library Selenium (EHC 58, 1986)