Source: FDA label
| Molecular formula | C153H225N43O49S |
|---|---|
| Molecular weight | 3482.7 g/mol |
| Registered trials | 3258 |
| PubChem CID | 16132283 |
| Brand names | Glucagon |
Mechanism of Action
12.1 Mechanism of Action Glucagon increases blood glucose concentration by activating hepatic glucagon receptors, thereby stimulating glycogen breakdown and release of glucose from the liver. Hepatic stores of glycogen are necessary for glucagon to produce an antihypoglycemic effect. Extrahepatic effects of glucagon include relaxation of the smooth muscle of the stomach, duodenum, small bowel, and colon.
Key takeaways
- Glucagon is FDA approved to treat severe hypoglycemia in adults and children with diabetes.
- It also serves as a diagnostic aid that temporarily slows gastrointestinal movement during radiologic exams.
- The hormone works by triggering the liver to break down stored glycogen and release glucose.
- More than 3,250 registered trials have studied glucagon or related pathways.
- Reported adverse events span drug ineffectiveness, breathing difficulty, kidney injury, and low blood pressure.
What glucagon is
Glucagon is a peptide hormone marketed under the brand name Glucagon. It is classified as an antihypoglycemic agent and a gastrointestinal motility inhibitor. In the body, it activates hepatic glucagon receptors, which stimulates the breakdown of stored glycogen and pushes glucose into the bloodstream. This effect depends on the liver having adequate glycogen reserves to draw from. Beyond its role in blood sugar, glucagon relaxes smooth muscle in the stomach, duodenum, small bowel, and colon.
What glucagon is approved for
Glucagon for Injection carries two approved uses. The first is treatment of severe hypoglycemia in pediatric and adult patients with diabetes mellitus. The second is as a diagnostic aid during radiologic examinations, where it temporarily inhibits movement of the gastrointestinal tract in adult patients so imaging can proceed. No boxed warning is present on the label.
What the evidence shows
More than 3,250 trials are registered involving glucagon or closely related mechanisms. Sampled studies illustrate the breadth of this research, including a withdrawn trial exploring imaging techniques for GLP1R-positive insulinomas and a phase 2 study, listed with unknown status, examining incretin and SGLT2 inhibitor combinations in congestive heart failure. Another study with unknown status looked at brain-gut interaction in irradiated patients with acromegaly.
Reported side effects
FAERS reports, which reflect submitted cases rather than confirmed incidence or causation, show a mix of systemic and organ-specific reactions. The most frequently logged terms are drug ineffective (372 reports) and dyspnoea (359), followed by acute kidney injury (318) and hypotension (291). Hypoglycaemia itself appears among reports (268), alongside condition aggravated (248), toxicity to various agents (234), and nausea (227). This pattern suggests a range of respiratory, renal, cardiovascular, and general reactions reported alongside glucagon use.
FAQ
What is glucagon used for?
Glucagon is approved to treat severe hypoglycemia, or dangerously low blood sugar, in adults and children with diabetes. It is also used as a diagnostic aid during radiologic exams to temporarily slow movement in the gastrointestinal tract. These are its only two FDA-approved uses.
How does glucagon work in the body?
Glucagon activates glucagon receptors in the liver, prompting the breakdown of stored glycogen and the release of glucose into the bloodstream. This antihypoglycemic effect requires the liver to have sufficient glycogen stores available. It also relaxes smooth muscle throughout the gastrointestinal tract, which is why it is used before certain imaging procedures.
Does glucagon have a boxed warning?
No, the current label for Glucagon for Injection does not carry a boxed warning.
What side effects have been reported with glucagon?
Reports submitted to FAERS most commonly mention drug ineffectiveness, dyspnoea, acute kidney injury, and hypotension. Hypoglycaemia, condition aggravated, toxicity to various agents, and nausea have also been reported. These figures reflect the number of submitted reports, not confirmed rates or proof that glucagon caused the reaction.
How much research exists on glucagon?
More than 3,250 trials have been registered that involve glucagon or closely related pathways. These range across different research areas, including imaging studies and investigations into metabolic and gastrointestinal conditions.
This page is an editorial information resource. It does not sell, prescribe, or recommend any medication.
Content is editorial information, not medical advice. Talk to your doctor before any treatment decision.
Sources: FDA label (DailyMed) ClinicalTrials.gov FAERS PubChem
Updated 2026-08-03