An inhibitor of DPP-4 (IC50 = 3.5-34 nM); also inhibits DPP-8 and DPP-9 (Ki = 810 and 95 nM, respectively) but not DPP-2 or FAPα; blocks the degradation of several circulating peptides, including incretins; reduces fasting and postprandial glucose levels and decreases inflammatory and oxidative stress.