Transforming a simple emergency remedy into a stable, intelligent therapeutic for modern diabetes care
For decades, glucagon has been known as a simple emergency remedy, a drug kept in kits to rescue people with diabetes from severe hypoglycemia. But this classic hormone is now getting a high-tech makeover. Scientists are re-engineering glucagon itself, transforming it from a fleeting rescue hormone into a powerful, stable therapeutic for modern diabetes care.
The challenge is that natural glucagon is notoriously unstable. It clumps into fibrils in solution, making it impractical for use in the advanced automated systems that represent the future of diabetes management. This article explores the molecular and formulation strategies scientists are using to overcome these hurdles, creating new glucagon-based therapies that are more effective, stable, and intelligent than ever before.
Glucagon is a 29-amino acid peptide hormone produced by the alpha cells in the pancreas. Its primary role is to act as a counterbalance to insulin. When blood sugar drops too low, glucagon is secreted, signaling the liver to break down stored glycogen into glucose and release it into the bloodstream—a process known as glycogenolysis4 5 .
For a long time, this was considered its sole function. However, a groundbreaking Duke University study published in September 2025 has completely upended this simplistic view. The research reveals that pancreatic alpha cells are far more flexible than previously believed.
Alpha cells can produce both glucagon and GLP-1, adapting their output based on metabolic needs.
When glucagon production is blocked, alpha cells increase GLP-1 output to maintain glucose control.
Not only can they produce glucagon, but they can also generate significant amounts of GLP-1 (Glucagon-Like Peptide-1), the very hormone mimicked by blockbuster drugs like Ozempic1 .
Even more surprising, when researchers blocked glucagon production in mice, the alpha cells didn't fail. Instead, they "switched gears," ramping up their production of GLP-1, which in turn enhanced insulin release and improved blood sugar control. This discovery shows that the body has a built-in backup system for blood sugar regulation, with GLP-1 acting as a "much more powerful signal" for insulin secretion than glucagon1 . This inherent flexibility points to new possibilities for treating type 2 diabetes by harnessing the body's own natural mechanisms.
Despite its critical biological role, natural glucagon is ill-suited for advanced therapeutic applications due to two key weaknesses:
In a liquid solution, glucagon molecules tend to stick together, forming fibrils and a gel-like substance. This makes it impossible to use in a mini-dose pump, as it would clog the delivery system2 .
The glucagon molecule is susceptible to degradation over time, particularly at neutral pH. A key amino acid, methionine at position 27, is vulnerable to oxidation, which can render the hormone less active7 .
These instabilities are why commercial glucagon is sold as a lyophilized (freeze-dried) powder that must be mixed with a liquid solution immediately before use—a process that is impractical and stressful during a hypoglycemic emergency. For emerging technologies like the bi-hormonal artificial pancreas, which requires a stable, pump-ready liquid glucagon, this is a major obstacle2 .
To overcome these challenges, researchers have developed a sophisticated toolkit, employing two main strategies: formulation chemistry and protein engineering.
Instead of changing the glucagon molecule itself, this approach uses special excipients (inactive ingredients) to "cage" and protect it. The goal is to immobilize glucagon in solution, preventing it from interacting with itself and forming fibrils.
LMPC (1-Myristoyl-2-hydroxy-sn-glycero-3-phosphocholine): A lysolecithin that forms lipid micelles around glucagon molecules. These micelles keep glucagon soluble and stable at a neutral pH.
DDM (N-dodecyl-β-D-Maltoside): A surfactant-like agent with a disaccharide "head" and a long-chain alcohol "tail." The sugar head protects the protein from aggregation, while the tail binds to hydrophobic areas on the molecule, preventing denaturation.
A more fundamental approach is to re-design the glucagon molecule from the ground up, swapping out unstable amino acids for more robust ones.
Replacing Serine at position 16 with Aib (aminoisobutyric acid) dramatically stabilizes the peptide's secondary structure.
Adjusting the peptide's isoelectric point by adding a C-terminal Aspartic acid-Glutamic acid dipeptide allows it to remain soluble at physiological pH.
Substituting the oxidation-prone Methionine at position 27 and unstable Glutamines at positions 3, 20, and 24 with more resilient amino acids.
The result is a glucagon analog that behaves like the native hormone in the body but possesses biophysical properties that are far more suitable for clinical use as a ready-to-use medicine7 .
| Specification | Minimal Goal | Optimal Goal |
|---|---|---|
| Shelf Life | 18 months at 5°C | 24 months at 5°C |
| In-Use Stability | Continued storage at 5°C | 30 days at 30°C |
| Pump Duration | 3-4 days | 7 days |
| Form | Clear, gel-free liquid | Clear, gel-free liquid |
Source: Adapted from specifications for stable liquid glucagon2
A pivotal 2025 study from Duke University provided a stunning new understanding of glucagon's biology, with major implications for its therapeutic potential1 .
The research team analyzed pancreatic tissue from both mice and humans across a range of ages, body weights, and diabetes statuses.
They used a high-specificity mass spectrometry assay designed to detect only the bioactive form of GLP-1.
In mouse studies, they genetically blocked two key enzymes: PC2 (glucagon production) and PC1 (GLP-1 production).
The core findings were twofold:
| Experimental Manipulation | Effect on Glucagon | Effect on GLP-1 | Overall Effect on Glucose Control |
|---|---|---|---|
| Block PC2 (disrupts glucagon) | Decreased | Increased | Improved |
| Block both PC2 and PC1 | Decreased | Decreased | Worsened (blood sugar spiked) |
Source: Summarized from Duke University mouse study data1
This experiment confirmed that GLP-1 production from alpha cells is not a minor side activity but a critical backup system. The ability to "switch gears" from a glucagon-dominant to a GLP-1-dominant state may be a key mechanism the body uses to maintain blood sugar balance during metabolic stress1 .
Perhaps the most exciting frontier is the development of "smart" combination therapies. Researchers at Indiana University School of Medicine have created a single molecule that fuses both insulin and glucagon6 .
When blood glucose is high, the insulin component dominates, lowering blood sugar.
When blood glucose is low, the glucagon component takes over, signaling the liver to release glucose.
Tested in rats, this molecule successfully lowered high blood glucose and helped raise low levels, reducing the need for emergency glucose injections. It also remained stable for weeks without refrigeration, a significant advantage for storage and distribution6 .
| Strategy | Mechanism | Key Advantage | Stage of Development |
|---|---|---|---|
| Stable Formulations | Excipients (LMPC, DDM) prevent fibrillation | Uses native hormone; ready-to-use liquid | Prototype formulations tested in animal models2 |
| Engineered Analogs | Chemically modified amino acid sequence | Inherently stable; no complex formulation needed | Research and design phase7 |
| Smart Hybrids | Single molecule combining insulin & glucagon | Glucose-responsive; reduces hypoglycemia risk | Positive results in animal studies6 |
Advancing this field requires specialized tools. Below is a table of key research reagents and their functions.
| Research Tool | Function in Experimentation | Example Use Case |
|---|---|---|
| Mass Spectrometry Assay | Precisely measures bioactive hormone levels (e.g., GLP-1) | Quantifying true hormone activity in pancreatic tissue1 |
| Glucagon ELISA Kits | Detects and measures glucagon concentration in samples | Monitoring glucagon levels in serum, plasma, or cell culture8 |
| PC1/3 and PC2 Enzymes | Key enzymes that process proglucagon into active hormones | Studying how hormone production is regulated in alpha cells1 5 |
| Glucagon Receptor Antagonists | Blocks the glucagon receptor to study its function | Investigating the effects of reducing glucagon signaling5 |
| Stable Cell Lines | Cell lines engineered with glucagon or GLP-1 receptors | Testing the biological potency and activity of new drug candidates2 5 |
The journey of engineering glucagon is a powerful example of how deepening our understanding of basic biology can drive medical innovation. By solving the stability problems that have long plagued this hormone, scientists are opening the door to a new generation of diabetes therapeutics.
From stable, pump-ready liquids to intelligent hybrid molecules that automatically regulate blood sugar, the future of glucagon is bright. These advances promise not only to improve the efficacy of diabetes treatment but also to dramatically reduce the constant fear of hypoglycemia, offering millions of people a safer and more manageable life.