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.