What Is Glucagon, and What Does It Do?

Medically Reviewed By Marina Basina, M.D.
Was this helpful?

Glucagon is a hormone that the pancreas secretes. It plays important roles in maintaining glucose levels and stimulating glucose production by the liver when blood sugar levels drop.  Glucagon works closely with another hormone, insulin, to keep blood sugar levels in a healthy range.

This article explores more about glucagon, what it does, the glucagon medications available, and the conditions related to atypical glucagon levels. Also, learn how your medical professional can check your glucagon level. 

Terms to understand

Two women exercising with kettle bells
Studio Firma/Stocksy United

Here are some terms that we will use throughout this article:

  • Glucose is a type of sugar the body uses for energy, sometimes called blood sugar.
  • Insulin is a hormone that the pancreas produces. It decreases blood sugar levels by telling cells to absorb sugar for current or later use.
  • Glycogen is the stored form of glucose kept in the liver and muscles for later use.
  • Glucagon is a hormone that the pancreas produces to help increase blood sugar levels.


Glucagon is a peptide hormone made of 29 amino acids. Most of your body’s glucagon comes from your pancreas, a small glandular organ in your abdomen behind your stomach.

Hormones are important chemicals in your body that carry messages and coordinate different functions. They tell your body what to do and when to do it. 

In the 1950s, Eli Lilly and Co. discovered how to extract and purify glucagon, leading to the use of glucagon as a treatment for severe hypoglycemia.  


An illustration showing how glucagon 
and insulin help regulate blood glucose levels.
Low blood glucose levels cause the pancreas to release glucagon, which stimulates glucose production in the liver. Illustration by Wenzdai Figueroa

Glucagon and insulin work closely together to keep your blood sugar in a healthy range

When you eat, your digestive system breaks down food into its nutritional parts. For example, proteins, vitamins, and sugars will break down and release into the blood for transportation to areas that need them. 

As sugar enters your blood, it triggers the secretion of insulin from your pancreas. This causes your blood sugar level to start decreasing as your cells absorb sugar. Glucagon then releases when sugar levels get low to prevent hypoglycemia. 

Glucagon helps stabilize your blood glucose level by:

  • triggering your liver to convert glycogen into glucose and add it to your bloodstream
  • preventing your liver from taking in and storing more glucose from the blood
  • breaking down other sources, such as lipids and fats, into glucose
  • decreasing your appetite

Other situations when the pancreas secretes glucagon include:

  • hypoglycemia
  • prolonged fasting
  • exercise
  • after protein-rich meals

Several conditions are related to atypical glucagon levels. 

Type 1 diabetes

Type 1 diabetes can affect anyone at any age. It is a condition in which a person’s body produces little or no insulin. As a result of low insulin levels, blood sugar levels become dangerously high. 

Symptoms often develop quickly and may include:

Treatment focuses on learning how to manage blood sugar levels through the use of insulin or other medications. Doctors may also recommend lifestyle changes, such as dietary modifications and exercise.

Learn more about type 1 diabetes.

Type 2 diabetes

Type 2 diabetes is when a person’s body does not respond well to insulin, resulting in high levels of blood sugar. The condition develops over many years and is the most common type of diabetes. While the symptoms are the same as type 1 diabetes, they may be subtle and slow to appear. 

Treatment also focuses on learning how to manage blood sugar levels and making lifestyle changes.

Learn more about type 2 diabetes.

Gestational diabetes

Gestational diabetes is diabetes that develops in people who are pregnant and have never had diabetes before. It usually goes away after the baby is born. According to the Centers for Disease Control and Prevention, a person who experiences gestational diabetes is usually at higher risk of developing type 2 diabetes later in life.

Learn more about gestational diabetes.


Prediabetes is a common condition affecting more than 1 in 3 adults in the United States. Many of them do not know they have prediabetes

Prediabetes is a condition in which blood sugar levels are higher than usual, but they are not as high as type 2 diabetes. Having prediabetes can put a person at a greater risk of type 2 diabetes, heart disease, and stroke. By making some lifestyle changes, people can take steps to reverse their prediabetes.

Learn more about prediabetes.

Glucagon medications

Glucagon injections and nasal sprays help in situations of severe hypoglycemia.

People with diabetes may take insulin or other medications to manage their diabetes and lower their blood sugar. In some cases, mismanagement of these medications may cause a person’s blood sugar to drop to a dangerously low level, resulting in hypoglycemia. 

A person experiencing hypoglycemia may not be conscious, so a caregiver may need to administer the medication. 

Glucagon injection

Glucagon injections, such as Gvoke, come as premixed pens. Because hypoglycemia can be an emergency, pharmaceutical makers designed this medication for quick administration. 

The medication in the pen is already mixed and stable. The person giving the medication needs to remove the cap and inject it into the person experiencing hypoglycemia. 

Glucagon nasal powder

Glucagon nasal powders, such as Baqsimi, are similar in size and administration to other typical nasal sprays.

The person giving the medication needs to remove the cap and spray a puff of the glucagon powder into a nostril, where it can quickly absorb into the bloodstream. This method may be preferable because it is needle-free. 

Side effects

Adverse side effects of glucagon medications may include:

Although they are rare, rebound hypoglycemia or worsening hyperglycemia may also occur.

Checking your glucagon levels

If your doctor feels it is necessary to check your glucagon level, they will order a simple lab test. You may need to fast for several hours before the test. 

During the test, a healthcare professional will use a small needle to take a blood sample from a vein in your arm. The blood will collect into a test tube or vial. After the test, the healthcare professional will cover the needle insertion site with clean gauze and a pressure bandage. Your doctor will then receive your lab results and review them with you. 


Glucagon is an important hormone that works closely with insulin to balance your blood sugar. The pancreas secretes glucagon in response to low blood sugar.

People with diabetes and prediabetes have atypical glucagon and insulin levels that need management with medications, like insulin, and lifestyle changes. Glucagon nasal powders and injections are available for people with diabetes in the event of severe hypoglycemia. 

Contact your doctor if you have diabetes or another health condition that may cause fluctuations in your glucagon levels.

Was this helpful?
Medical Reviewer: Marina Basina, M.D.
Last Review Date: 2022 Nov 17
View All Endocrinology and Metabolism Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Diabetes. (2022). https://www.cdc.gov/diabetes/index.html
  2. Glucagon and other emergency glucose products. (n.d.) https://diabetes.org/healthy-living/medication-treatments/glucagon-other-emergency-glucose-products
  3. Glucagon blood test. (2021). https://medlineplus.gov/lab-tests/glucagon-blood-test/
  4. Morris, C. H., et al. (2022). Glucagon. https://www.ncbi.nlm.nih.gov/books/NBK559195/
  5. Rix, I., et al. (2019). Glucagon physiology. https://www.ncbi.nlm.nih.gov/books/NBK279127/