Glucagon: effects, uses and side effects
Clinical review pending
Glucagon raises blood glucose and is used as an emergency medicine for severe hypoglycemia. How it works, which uses are approved in the United States and its risks.
Glucagon raises blood glucose. As an emergency medicine, it is used for severe hypoglycemia when a person cannot safely eat or drink. How well it works also depends on the liver’s sugar stores: if they are depleted, for example after prolonged fasting, its effect may be weaker.
What is glucagon?
The pancreas produces glucagon, a hormone containing 29 amino acids. It counteracts insulin and raises blood glucose when it falls. As a medicine, it helps treat severe hypoglycemia—a dangerously low blood glucose level. This can occur in people with diabetes, especially those treated with insulin.
Glucagon is available, for example, as the ready-to-use Gvoke injector and as a nasal powder called Baqsimi. Sales of the GlucaGen HypoKit emergency kit were discontinued in the United States in 2024. 1
How does glucagon work?
Glucagon binds to receptors on liver cells. It stimulates the liver to break down stored glycogen into glucose and make new glucose. These processes are called glycogenolysis and gluconeogenesis. The liver releases glucose into the blood, raising blood glucose within minutes. This is why glucagon can be used in an emergency when a person with hypoglycemia cannot eat or drink.
Glucagon may work less well when the liver’s sugar stores are depleted. This can happen after prolonged fasting or during starvation.
Glucagon also relaxes the smooth muscle of the gastrointestinal tract. This effect is used as a diagnostic aid during certain imaging procedures.
In a study involving adults with type 1 diabetes, glucagon nasal powder raised blood glucose about as effectively as injected glucagon. Nasal powder can be administered without an injection or prior mixing, making emergency use easier. 2
Is glucagon FDA-approved?
Yes. The US Food and Drug Administration has approved glucagon for treating severe hypoglycemia and as a diagnostic aid in gastrointestinal imaging. The approved use depends on the particular product.
| Product | Formulation | FDA approval |
|---|---|---|
| Glucagon for injection, including recombinant GlucaGen | Injection | Approved for decades |
| Gvoke 3 | Ready-to-use injector | 2019 |
| Baqsimi 4 | Ready-to-use nasal powder | 2019 |
What is glucagon prescribed for?
People with diabetes receive glucagon as an emergency medicine for severe hypoglycemia. A caregiver usually administers it when the person cannot safely take sugar by mouth. Injectable forms are also used during radiological examinations to relax intestinal muscle.
Glucagon must not be used in people with a pheochromocytoma or an insulinoma. A pheochromocytoma is a tumor that produces hormones belonging to the catecholamine group; an insulinoma is an insulin-producing tumor.
What side effects can occur?
According to the product information for the injectable formulation (3) and the nasal powder (4), common side effects include:
- Nausea and vomiting
- Headaches
- Injection-site reactions, or nasal and eye symptoms with the nasal powder
More serious risks include:
- A marked rise in blood pressure in people with a pheochromocytoma
- Recurrent hypoglycemia in people with an insulinoma
- Rare allergic reactions