The transition from normal glucose tolerance to overt type 2 diabetes mellitus (T2D) encompasses a variety of glycemic abnormalities that are commonly referred to as 'prediabetes'. While intensive lifestyle interventions are the cornerstone of T2D prevention, developing safe, cost-effective adjunct therapeutic strategies is a clinically relevant goal. Cinnamon supplementation has been shown to improve fasting plasma glucose in patients with T2D. This placebo-controlled, randomized study will determine if cinnamon improves glucose homeostasis in patients with prediabetes over a 12-week period.