A comprehensive review examines the latest strategies — from chemical modifications to nanoparticles and microneedles — for making peptide and protein drugs effective when taken orally instead of by injection.
4 GI barriersStomach acid, digestive enzymes, mucus lining, and intestinal wall — the four obstacles that must be overcome for oral peptide drug delivery
What the researchers found
The review identifies four main gastrointestinal barriers to oral peptide delivery: harsh pH environment, enzymatic degradation, the mucus layer, and the intestinal epithelial barrier. Current strategies to overcome these include chemical modifications (like PEGylation and cyclization), permeation enhancers that temporarily open tight junctions, encapsulation techniques (enteric coatings, hydrogels), and novel delivery systems including ingestible microneedle devices and nanoparticle-based carriers.
The authors conclude that no single strategy adequately overcomes all four barriers, and that synergistic integration of multiple approaches — combining protection, permeation enhancement, and targeted delivery — is the most promising path toward effective oral peptide therapeutics.
Why it matters
The ability to take peptide drugs orally instead of by injection would dramatically improve patient compliance and quality of life for millions of people managing conditions like diabetes, obesity, and osteoporosis. Oral delivery could also reduce healthcare costs and expand access to peptide therapies in settings where injection-based treatment is impractical.
How the study worked
This is a comprehensive narrative review of the recent literature on oral delivery strategies for protein and peptide therapeutics. The authors surveyed and critically evaluated published research on chemical modifications, permeation enhancers, encapsulation techniques, and novel delivery systems, providing comparative analysis of each approach's advantages and limitations.
What this study cannot tell us
As a review, this paper synthesizes existing research rather than generating new data. Many of the strategies discussed remain in preclinical stages, and the gap between laboratory success and commercial oral peptide products remains large. The review acknowledges that translating multi-barrier strategies into practical, scalable formulations is a major unresolved challenge.
How to read the evidence
This is a narrative review of the current state of oral peptide delivery technology. It synthesizes a broad range of preclinical and early clinical research but does not provide new experimental data. Most strategies reviewed are at the preclinical stage.
When this study was published
Published in 2026, this review represents the very latest thinking on oral peptide delivery strategies, incorporating recent advances in nanotechnology, microneedle devices, and formulation science.
The bigger picture
As peptide therapeutics become one of the fastest-growing drug classes — with GLP-1 drugs, insulin, and others reaching massive patient populations — the push for oral formulations has become a major industry priority. Oral semaglutide (Rybelsus) proved the concept is achievable, and this review maps the broader technological landscape that could extend oral delivery to many more peptide drugs.
Questions still open
- Which combination of delivery strategies will prove most effective and commercially viable for oral peptide drugs?
- Can ingestible microneedle devices achieve the bioavailability and consistency needed for widespread clinical adoption?
- How will oral peptide formulations compare to injectable versions in terms of cost-effectiveness and patient outcomes?
Common questions
Why can't most peptide drugs be taken as pills?
Are any peptide drugs already available in oral form?
Read the original research
Strategies for overcoming multiple barriers of oral administration of protein and peptide therapeutics.
Materials today. Bio, 37, 102763
Citation
Wang, Xiaofan; Wang, Keke; Fang, Yitan; Zhang, Youxi; Yi, Lixin; Li, Xiaohong; Zhao, Qinfu; Zhu, Xu; Cai, Shuang; Wan, Long. (2026). Strategies for overcoming multiple barriers of oral administration of protein and peptide therapeutics.. Materials today. Bio, 37, 102763. https://doi.org/10.1016/j.mtbio.2026.102763