Creatinine

Creatinine is the cyclic anhydride metabolite formed from creatine through non-enzymatic dehydration in muscle tissue. It is found across a range of muscle foods, and its levels, together with those of creatine, may indicate the condition and quality of meat products. Because creatinine formation continues during storage and heating, its ratio to creatine has been explored as a marker of processing intensity and product history. In human physiology it is the familiar waste product of muscle metabolism excreted in urine and used clinically to assess kidney function.