The journey of bioactive peptides in vivo: cutting-edge advances in absorption, transport, and bioavailability.

Bioactive peptides, consisting of 2-20 amino acid residues, constitute a class of biological active molecules that exert crucial regulatory functions in various physiological processes. Contemporary research has revealed that these peptides exhibit remarkable multifunctional properties, including antioxidant, antihypertensive, immunomodulatory, hypoglycemic, and antitumor activities, highlighting their considerable therapeutic potential in health maintenance and disease intervention. However, their clinical application faces substantial challenges due to poor bioavailability, primarily attributed to the biochemical barrier imposed by gastric acid and digestive enzyme degradation, the intricate multilayer physical barriers of the intestinal epithelium, and intrinsic physicochemical properties such as molecular size and hydrophobicity. Notably, the in vivo transport mechanisms of bioactive peptides involve sophisticated physiological processes, and a thorough elucidation of their absorption kinetics and transport pathways is essential for developing efficacious peptide-based therapeutics. This review systematically examines the multifaceted barrier mechanisms affecting peptides digestion and absorption, elucidates their in vivo transport pathways, and proposes cutting-edge strategies to enhance bioavailability. These presented insights not only establish a comprehensive theoretical framework and practical guidance for optimizing peptide absorption and deliver, but also open provide novel research perspectives to facilitate their clinical applications.