Possible Interaction: Creatine and Creatinine

“Although the levels of creatine in each formulation were not determined, a substantial conversion of creatine into creatinine has been reported in many formulations and may explain the present findings.”

“ Creatine supplementation resulted in greater cyst growth and worsened renal function in the Han:SPRD-cy rat, evidenced by greater kidney weights (2.87 ± 0.…; P = 0.0167) and serum urea concentrations (23.96 ± 0.92 versus 20.65 ± 1.06 mmol/L; P = 0.0230), and lower creatinine …).”

“ Food creatine concentration was 5- to 12 -fold greater than creatinine ; food creatine and creatinine were increased 4- and 10-fold, respectively, in the high beef diet compared with the control diets.”

“In serum, creatine was found to contribute to creatinine up to 20% when measured by the present GC-MS method.”

“Urinary excretions of guanidinoacetate and creatine correlated positively with creatinine clearance.”

“ Urine creatine/creatinine ratio was increased and creatine uptake in fibroblasts was impaired in both patients.”

“Because creatine is converted to creatinine in the body, supplementation with large doses of creatine may falsely elevate creatinine concentrations.”

“Since creatine supplementation may increase creatinine levels, it may act as a false indicator of renal dysfunction.”

“Studies on solutions containing creatine and creatinine in various proportions show that in the presence of an excess of creatinine a considerable fraction of the creatine content escapes conversion.”

“In connexion with this last postulate Beardw states that the ingestion of creatinine in rats and man greatly stimulates the formation of creatine and creatinine.”