Comprehensive Review: Overcoming the Barriers to Getting Bioactive Peptides to Work as Oral Medicines

Three major barriers limit oral bioactive peptide delivery — bitter taste, GI instability, and poor transmembrane transport — with emerging solutions including chemical modification, osmotic technology, liposomes, nanoparticles, and hydrogels showing varying degrees of success.

Comprehensive literature review covering factors affecting oral bioactive peptide absorption, current enhancement technologies, and delivery system platforms (liposomes, emulsions, polymer nanoparticles, hydrogels) for oral peptide delivery.

Peptide drugs and functional food peptides are one of the fastest-growing sectors in pharma and nutrition, but the inability to take them orally is the single biggest barrier to widespread use. Solving oral delivery would transform peptide therapeutics — replacing daily injections for millions of diabetes, obesity, and hormone therapy patients with simple pills.

As GLP-1 agonists, antimicrobial peptides, and other peptide therapeutics continue to expand, the oral delivery challenge becomes increasingly urgent. Oral semaglutide's commercial success proves the concept works but currently requires large doses and an absorption enhancer. This review maps the full landscape of approaches that could make oral peptide delivery more efficient, more affordable, and applicable to a wider range of peptide drugs and functional food products.

Review article — does not present new experimental data. Many delivery technologies reviewed are still at the lab scale. Head-to-head comparisons between different approaches are largely absent. Cost-effectiveness and manufacturing scalability of advanced delivery systems are often overlooked. Regulatory pathways for novel delivery systems add complexity and time.