This randomized controlled trial aims to evaluate the therapeutic effects of pure Ceylon cinnamon (Cinnamomum verum) supplementation combined with a structured self-efficacy-based educational program on glycemic control, lipid profiles, and neuropathic pain in adult patients with type 2 diabetes mellitus (T2DM) and painful diabetic peripheral neuropathy (PDPN). A total of 900 participants will be randomly assigned to three parallel arms: a standard care control group, a Ceylon cinnamon supplementation group (1,000 mg/day), and a combined intervention group (Ceylon cinnamon supplementation plus the self-efficacy educational program) over a 6-month period. The study hypothesizes that the combined approach will significantly improve glycemic parameters, reduce neuropathic pain severity, and enhance metabolic profiles compared to standard care alone.