Gut-Penetrating Peptide Brings Insulin Closer to an Oral Pill

Researchers at Kumamoto University developed a cyclic DNP peptide that enables insulin to cross the intestinal barrier, achieving about 33–41% oral bioavailability in diabetic mouse models. They demonstrated two approaches—a mixing method where the peptide interacts with zinc-stabilized insulin hexamers, and a covalent DNP–insulin conjugate created via click chemistry—both producing effective glucose lowering. Once-daily dosing maintained normal glycemia for three days, marking a significant step toward practical oral insulin and potentially reducing injectable insulin needs; translational studies in larger animals and human intestinal systems are planned.