Comparison of antihyperglycemic effects of creatine and metformin in type II diabetic patients.

PURPOSE To compare the antihyperglycemic effects of metformin and creatine in recently detected type II diabetics in a short-term clinical study. METHODS In a 14 day simmetrically randomized crossover study, recently detected type II diabetics received either creatine (2x3 g/day) or metformin (2x500 mg/day) for five days, followed by two days of washout, followed by cross-over to the opposite treatment for the next five days. Fasting and post-prandial (-15, 60, 90, 120, 180 and 240 min) blood glucose, insulin, c-peptide, creatine and lactate were measured every other day for the duration of treatment, and HbA1c only at the begining and at the end of the study. RESULTS Both creatine and metformin decreased glucose concentrations to similar levels at all time points vs. basal glucose values [-15, 60, 90, 120, 180, and 240 min]: 11.1+/-0.75 vs 9.1+/-0.55a vs 8.8+/-0.59b, 14.4+/-0.6 vs 12.9+/-0.47a vs 13.1+/-0.55a, 14.8+/-0.58 vs 13.0+/-0.46b vs 13.3+/-0.55a, 14.1+/-0.6 vs 11.9+/-0.42b vs 12.5+/-0.51a, 12.2+/-0.6 vs 9.6+/-0.36c vs 9.9+/-0.38c, and 10.1+/-0.47 vs 7.8+/-0.36c vs 8.4+/-0.4b; (aP < 0.05; bP < 0.01; cP < 0.001 vs. basal glucose values). Neither treatment altered insulin, c-peptide, or HbA1c. Lactate varied during the day, but never reached the upper level of the safety reference range. CONCLUSION Short-term treatment with creatine and metformin elicits similar glucose lowering effects in recently detected type II diabetics. Further studies are necessary to determine the effect of creatine on long-term glucose and insulin regulation.