45180 - co-factors to metabolism (efsa foodex2) 45210 - creatine-creatinine (efsa foodex2) The group includes Creatine-creatinine used in fortified foods and dietary supplements. Creatine is a nitrogenous organic acid that occurs naturally in vertebrates and helps to supply energy to all cells in the body, primarily muscle. This is achieved by increasing the formation of adenosine triphosphate (ATP). The part consumed/analysed is by default the whole or a portion of it representing the observed heterogeneity. ] and [https://en.wikipedia.org/wiki/Creatinine] requires discussion