What is GLP-1 and how does it work?

SUMMARY

GLP-1 (glucagon-like peptide-1) is a hormone naturally produced by your body after you eat. It plays a role in blood glucose regulation, digestion and appetite signalling.

You may also have heard of GLP-1 medications, which are prescription medications designed to activate the same biological pathway.

This blog explains what GLP-1 is, what it does in the body, how GLP-1 medications work, the different types available in Canada and how to access them.

WHAT YOU'LL LEARN

• What GLP-1 is
• What GLP-1 does in the body
• What a GLP-1 receptor agonist is
• The different types of medications that act on the GLP-1 pathway
• What GLP-1 medications are used for
• How to get a GLP-1 medication in Canada
• Whether “natural GLP-1” supplements and patches are the same as prescription medications

You may have heard the term GLP-1 in the news, on social media or while researching prescription treatment options.

Despite the growing attention, GLP-1 isn't a new substance. It's a hormone your body naturally produces after eating.

Understanding what GLP-1 does in the body can make it easier to understand how medications that act on this pathway work.

What is GLP-1?

GLP-1 stands for glucagon-like peptide-1, a hormone naturally produced by the body after eating.

Specialized cells in the lining of the intestines release GLP-1 in response to food. Smaller amounts are also produced in certain areas of the brain.

GLP-1 belongs to a group of hormones called incretins. These hormones help coordinate the body's response to a meal, including processes involved in blood glucose regulation, digestion and appetite signalling.

GLP-1 levels rise after eating, but the hormone doesn't remain active for very long. An enzyme called DPP-4 breaks down naturally occurring GLP-1 within minutes.

This short duration of activity became an important consideration in the development of medications that act on the GLP-1 pathway.

What does GLP-1 do in the body?

GLP-1 is part of a signalling system that helps the body respond to food. Its activity influences several processes:

• Insulin signalling: GLP-1 helps regulate insulin release in response to changes in blood glucose.
• Glucagon regulation: It influences the release of glucagon, a hormone involved in maintaining blood glucose levels.
• Gastric emptying: It affects how quickly food moves from the stomach into the small intestine.
• Appetite signalling: GLP-1 also interacts with areas of the brain involved in appetite and feelings of fullness.

Together, these processes form part of the body's normal response to eating.

What is a GLP-1 receptor agonist?

A GLP-1 receptor agonist is a medication designed to activate the same receptors targeted by naturally occurring GLP-1.

You may hear these medications referred to as:

• GLP-1 agonists
• GLP-1 receptor agonist medications
• GLP-1 medications
• GLP-1 drugs

The term “agonist” simply means a substance that activates a receptor.

Unlike naturally occurring GLP-1, which is broken down quickly, these medications are designed to remain active in the body for much longer. Depending on the medication and formulation, they may be taken daily or weekly, and some are administered by injection while others are available as oral medications.

What are the different types of GLP-1 medications?

“GLP-1” is often used as a general term, but medications that act on this pathway are not all the same.

Single GLP-1 receptor agonists

These medications activate the GLP-1 receptor. Examples include semaglutide, dulaglutide, liraglutide and exenatide.

They can differ in their molecular structure, formulation, administration and approved uses.

Dual GIP/GLP-1 receptor agonists

Some medications act on two hormone receptors: GIP and GLP-1.

Tirzepatide is an example. GIP, or glucose-dependent insulinotropic polypeptide, is another hormone involved in the body's response to food.

Because these medications act on two receptor pathways, they are more accurately described as dual GIP/GLP-1 receptor agonists rather than simply GLP-1 medications.

What about triple agonists?

Researchers are also studying medications designed to activate GLP-1, GIP and glucagon receptors. These are investigational treatments and are not currently authorized for use in Canada.

What are GLP-1 medications used for?

Different medications that act on the GLP-1 pathway have different Health Canada-approved uses.

Depending on the specific medication, they may be authorized for uses related to type 2 diabetes or weight management in eligible individuals. Not every medication in this broader group is authorized for the same purposes.

Whether a particular medication is appropriate depends on factors such as:

• Medical history
• Current medications
• Existing health conditions
• Treatment goals
• The specific medication and its approved uses

A licensed Canadian practitioner can assess these factors and determine whether a prescription treatment may be appropriate.

How do you get a GLP-1 medication in Canada?

GLP-1 medications are prescription-only medications in Canada.

To obtain one, you'll need an assessment from a licensed Canadian practitioner. During an assessment, the practitioner may review:

• Your medical history
• Current medications
• Existing health conditions
• Relevant laboratory results, when appropriate

If a prescription is appropriate, it can be dispensed by a licensed Canadian pharmacy.

Are “natural GLP-1” supplements and patches real?

As interest in GLP-1 medications has grown, so has the number of products marketed as “natural GLP-1” alternatives. These may include supplements, powders, drops, patches and herbal products.

These products are not the same as prescription GLP-1 receptor agonists and should not be assumed to activate GLP-1 receptors in the same way.

Health Canada has also warned consumers about unauthorized GLP-1 products sold through online and other unregulated channels.

If a product claims to provide prescription-like GLP-1 effects without requiring a prescription, approach those claims cautiously. For prescription medications, use a licensed Canadian pharmacy and speak with a practitioner or pharmacist if you have questions.

When should you speak with a practitioner?

If you're considering a GLP-1 medication or have questions about blood glucose, weight management or prescription treatment options, a practitioner can help you understand what options may be appropriate.

This is particularly important if you have existing health conditions, take prescription medications or are considering starting, stopping or changing a medication.

A pharmacist can also answer questions about your prescription, potential interactions and how your medication should be taken.‍

Frequently Asked Questions

What is a GLP-1?

GLP-1, or glucagon-like peptide-1, is a hormone naturally produced by the body after eating. It is involved in processes including blood glucose regulation, digestion and appetite signalling.

Is GLP-1 a hormone or a medication?

GLP-1 is a hormone. GLP-1 receptor agonists are medications designed to activate the same receptors as naturally occurring GLP-1.

How do GLP-1 medications work?

GLP-1 receptor agonists activate receptors involved in processes such as insulin and glucagon regulation, blood glucose control, gastric emptying and appetite signalling.

Are GLP-1 medications used for type 2 diabetes?

Certain GLP-1 receptor agonists are authorized in Canada for the management of type 2 diabetes. The appropriate treatment depends on the specific medication and the individual's health needs.

Are GLP-1 medications used for weight management?

Certain medications that act on the GLP-1 pathway are authorized in Canada for weight management in eligible individuals. A practitioner can determine whether a particular treatment is appropriate.

Which GLP-1 medication is best?

There isn't one option that is appropriate for everyone. Different medications have different active ingredients, formulations, approved uses and product instructions. A practitioner can help determine whether a particular treatment is appropriate based on your health needs.

Can you buy GLP-1 medications over the counter in Canada?

No. GLP-1 medications are prescription-only medications in Canada.

Can you get a GLP-1 medication as a pill?

Yes. Although many medications that act on the GLP-1 pathway are administered by injection, oral options are also available in Canada.

Are “natural GLP-1” supplements the same as GLP-1 medications?

No. Products marketed as “natural GLP-1” alternatives are not the same as prescription GLP-1 receptor agonists and should not be assumed to activate GLP-1 receptors in the same way.