Bone & endocrine

Glucagon

The pancreatic hormone that raises blood glucose, licensed as emergency treatment for severe hypoglycaemia.

Strong evidenceApproved drugAdd to compare

What it is

Glucagon is a 29-amino-acid pancreatic hormone, made recombinantly for medicine. It raises blood glucose by releasing stored glycogen and driving glucose production in the liver - the physiological opposite of insulin. It is licensed as an emergency treatment for severe hypoglycaemia, including a nasal powder form, and as a relaxant for gut imaging.

How it works

1
Binds glucagon receptors on liver cells, triggering glycogen breakdown and glucose release.
2
Stimulates gluconeogenesis from amino acids and lactate.
3
Relaxes gastrointestinal smooth muscle, which is why it is used in gut imaging.
4
Stimulates insulin release from beta cells, which is used in diagnostic testing.
5
Works within minutes but depends on the liver having glycogen available.

What it's studied for

Severe hypoglycaemia in type 1 and type 2 diabetes

Nasal glucagon as a needle-free rescue (randomised trials)

Beta-blocker and calcium channel blocker overdose protocols

Gastrointestinal and biliary imaging to reduce motility

Diagnostic testing in congenital hyperinsulinism

Reported and studied effects

Blood glucose rise within 5 to 15 minutes
Restored consciousness in the large majority of severe hypoglycaemia episodes in trials
Nausea and vomiting in a substantial share of treated episodes
Relaxation of the stomach and duodenum during imaging
Transient hyperglycaemia needing follow-up carbohydrate

Research protocol notes

Research context only

Research context only - emergency medicine. The licensed adult dose is 1 mg intramuscularly or subcutaneously, 0.5 mg if under 25 kg, or 3 mg intranasally; hospital infusion protocols for overdose run in milligrams per hour under continuous monitoring. Nasal glucagon trials measured glucose response at 30 minutes.

These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.

Possible side effects and contraindications

Safety profile

Possible side effects

Nausea and vomiting, very common
Headache
Transient hyperglycaemia
Tachycardia
Injection-site reactions
Rebound hypoglycaemia if no carbohydrate is eaten afterwards
Nasal irritation with the powder

Contraindications and cautions

Phaeochromocytoma
Insulinoma, where it can provoke delayed hypoglycaemia
Prior hypersensitivity
Starvation or glycogen-depleted states where it may not work

A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.

Evidence assessment

Strong evidenceReplicated, large human trials

Replicated, large human trials

Randomised controlled trials of injectable and nasal glucagon in hypoglycaemia, decades of emergency use, and regulatory approval in both the EU and US.

References

References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.

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