A novel azapeptide GLP-1 analogue with a nitrogen-swapped backbone resisted enzymatic degradation for over 24 hours, maintained potent receptor activity, and reduced weight and improved glucose control in obese mice.
>24 hours DPP-4 resistanceThe azapeptide GLP-1 analogue resisted the enzyme that normally destroys native GLP-1 within minutes, while maintaining picomolar receptor potency
What the researchers found
The lead azapeptide analogue, AzaA8/R34-GLP-1 (AzaA8), demonstrated resistance to dipeptidyl peptidase-4 (DPP-4) degradation for over 24 hours — a dramatic improvement over native GLP-1 which is degraded within minutes. Despite the backbone modification, AzaA8 maintained picomolar potency at the GLP-1 receptor.
In lean mice, AzaA8 improved oral glucose tolerance. In high-fat diet-induced obese mice, chronic administration reduced body weight, decreased both leptin and insulin levels, and enhanced glucose handling. No detectable inflammatory adverse effects were observed, supporting the safety profile of this azapeptide approach.
Why it matters
Current GLP-1 drugs like semaglutide and liraglutide use various strategies to extend their half-life, but they still require modifications like fatty acid chains or PEGylation. Azapeptide substitution represents an entirely different approach — modifying the peptide backbone itself to resist enzymatic breakdown while preserving biological activity. If this translates to humans, it could lead to a new class of longer-lasting, potentially simpler GLP-1 therapies for diabetes and obesity.
How the study worked
Researchers used solid-phase peptide synthesis to create GLP-1 analogues with aza-substitutions (replacing α-carbon with nitrogen) at protease-sensitive residues. They evaluated DPP-4 resistance in vitro, measured GLP-1 receptor signaling potency, and assessed plasma half-life in mice. In vivo efficacy was tested in lean mice (oral glucose tolerance) and in high-fat diet-induced obese mice (chronic administration measuring body weight, glucose handling, insulin, leptin, and inflammatory markers).
What this study cannot tell us
This is a preprint (bioRxiv) that has not yet undergone peer review. All experiments were conducted in mice, and translation to humans is uncertain. Specific dosing details and exact weight loss percentages were not provided in the abstract. Long-term safety and efficacy data beyond the chronic dosing period are unavailable. The comparison was against unmodified GLP-1, not against approved drugs like semaglutide.
How to read the evidence
This is a preclinical study published as a preprint (not yet peer-reviewed). While the in vitro and in vivo results are promising and include both lean and obese mouse models, the lack of peer review, human data, and comparison to approved therapies limits the evidence grade.
When this study was published
Published as a 2025 preprint on bioRxiv, this represents cutting-edge peptide engineering research. As a preprint, findings should be interpreted with caution pending peer review, but the approach is timely given the enormous interest in GLP-1 therapeutics.
The bigger picture
The global race to improve GLP-1-based therapies is intense. While current drugs already work well, they rely on complex modifications to extend half-life. Azapeptide technology offers an elegant alternative — a minimal chemical change that fundamentally alters proteolytic vulnerability. This proof-of-concept could extend beyond GLP-1 to any therapeutic peptide limited by rapid degradation, potentially transforming the broader peptide drug development landscape.
Questions still open
- How would AzaA8 compare directly to approved GLP-1 receptor agonists like semaglutide in head-to-head preclinical studies?
- Can the azapeptide modification strategy be applied to other therapeutic peptides beyond GLP-1?
- What is the actual plasma half-life of AzaA8 in mice, and what half-life could be expected in humans?
Common questions
What is an azapeptide and how does it make GLP-1 last longer?
Could this become a new type of weight loss or diabetes drug?
Read the original research
Protease-Resistant Azapeptide GLP-1 Analogue Improves Metabolic Control in Diet-Induced Obesity.
bioRxiv : the preprint server for biology
Citation
He, Mingzhu; Cheng, Kai Fan; VanPatten, Sonya; Torres, Marcelo D T; Jabari, Bayan Al; Mughrabi, Ibrahim T; Ballarín-González, Borja; Son, Myoungsun; de la Fuente-Nunez, Cesar; Al-Abed, Yousef. (2025). Protease-Resistant Azapeptide GLP-1 Analogue Improves Metabolic Control in Diet-Induced Obesity.. bioRxiv : the preprint server for biology. https://doi.org/10.1101/2025.05.09.653092