What is GLP-1? A natural hormone
GLP-1 stands for Glucagon-Like Peptide-1. It is a hormone that your body naturally produces in the small intestine after you eat. GLP-1 plays a central role in how your body processes food and regulates energy.
Your body's natural GLP-1
When you eat, specialized cells in your intestine (called L-cells) release GLP-1 into your bloodstream. This natural hormone sends signals to your brain that help you feel satisfied after eating. It also stimulates insulin release and slows down the speed at which food leaves your stomach.
Natural GLP-1 is broken down quickly in the body — typically within minutes — by an enzyme called DPP-4. This rapid breakdown is one reason why GLP-1 medications were developed: to provide a longer-lasting version of this beneficial hormone.
GLP-1 receptor agonist medications
GLP-1 receptor agonists are medications that mimic the action of natural GLP-1 but are engineered to last much longer in the body. While natural GLP-1 breaks down in minutes, these medications can remain active for days — which is why most are taken as a once-weekly injection.
The first GLP-1 receptor agonist, exenatide (Byetta), was FDA-approved in 2005 for type 2 diabetes. Since then, the class has expanded significantly. In 2021, semaglutide (Wegovy) became the first GLP-1 approved specifically for chronic weight management in adults, marking a major shift in how obesity is treated as a medical condition.
A brief history of GLP-1 medications
| Year | Milestone |
|---|---|
| 2005 | Exenatide (Byetta) becomes the first FDA-approved GLP-1 receptor agonist for type 2 diabetes |
| 2010 | Liraglutide (Victoza) approved for type 2 diabetes — the first once-daily GLP-1 |
| 2014 | Liraglutide (Saxenda) approved for chronic weight management |
| 2017 | Semaglutide (Ozempic) approved for type 2 diabetes |
| 2019 | Oral semaglutide (Rybelsus) approved — the first oral GLP-1 medication |
| 2021 | Semaglutide (Wegovy) approved for chronic weight management |
| 2022 | Tirzepatide (Mounjaro) approved for type 2 diabetes — a dual GIP/GLP-1 agonist |
| 2023 | Tirzepatide (Zepbound) approved for chronic weight management |
How GLP-1 medications work in the body
GLP-1 receptor agonists work through several interconnected mechanisms. Here is a simplified overview of the primary ways these medications affect the body.
Appetite regulation
GLP-1 medications act on receptors in the hypothalamus — the brain region that controls hunger and satiety. By activating these receptors, the medications help reduce appetite and decrease what researchers call “food noise” — the persistent thoughts about food that many people experience.
Clinical trials have documented significant reductions in caloric intake among participants taking GLP-1 medications.
Slowed gastric emptying
GLP-1 medications slow the rate at which food moves from the stomach into the small intestine. This process, called delayed gastric emptying, means food stays in the stomach longer — helping you feel full for an extended period after eating.
This mechanism contributes to both reduced food intake and more stable blood sugar levels after meals.
Blood sugar control
GLP-1 medications stimulate insulin secretion in a glucose-dependent manner — meaning they help your pancreas release insulin when blood sugar is elevated, but not when it is already low. This reduces the risk of hypoglycemia compared to some other diabetes medications.
This is the primary reason GLP-1 receptor agonists were originally developed for type 2 diabetes management.
FDA-approved GLP-1 medications
Several GLP-1 receptor agonists have been approved by the FDA for different indications. Approved indications and formulations may vary — always consult your prescribing healthcare provider.
Semaglutide medications
| Brand | Generic | Manufacturer | Approved | Indication | Administration |
|---|---|---|---|---|---|
| Ozempic® | Semaglutide | Novo Nordisk | 2017 | Type 2 diabetes | Weekly injection |
| Wegovy® | Semaglutide | Novo Nordisk | 2021 | Chronic weight management | Weekly injection |
| Rybelsus® | Semaglutide (oral) | Novo Nordisk | 2019 | Type 2 diabetes | Daily oral tablet |
Tirzepatide medications (dual GIP/GLP-1)
| Brand | Generic | Manufacturer | Approved | Indication | Administration |
|---|---|---|---|---|---|
| Mounjaro® | Tirzepatide | Eli Lilly | 2022 | Type 2 diabetes | Weekly injection |
| Zepbound® | Tirzepatide | Eli Lilly | 2023 | Chronic weight management | Weekly injection |
Note: Tirzepatide is a dual GIP/GLP-1 receptor agonist, meaning it targets both the GLP-1 and GIP (Glucose-dependent Insulinotropic Polypeptide) receptors. This dual mechanism distinguishes it from pure GLP-1 receptor agonists.
Other notable GLP-1 receptor agonists
| Brand | Generic | Manufacturer | Indication | Administration |
|---|---|---|---|---|
| Saxenda® / Victoza® | Liraglutide | Novo Nordisk | Victoza: Type 2 diabetes; Saxenda: Weight management | Daily injection |
| Trulicity® | Dulaglutide | Eli Lilly | Type 2 diabetes | Weekly injection |
View the complete GLP-1 medications reference guide
What the clinical trials show
GLP-1 medications have been studied in some of the largest clinical trials in obesity and diabetes medicine. Here is what the published data shows.
| Semaglutide (Wegovy®) — STEP trials | Tirzepatide (Zepbound®) — SURMOUNT trials | |
|---|---|---|
| Average body weight loss | ~14.9% | ~20.9% (highest dose) |
| Trial | STEP 1 (Semaglutide Treatment Effect in People with obesity) | SURMOUNT-1 |
| Participants | 1,961 adults | 2,539 adults |
| Duration | 68 weeks | 72 weeks |
| Placebo | 2.4% average loss | 3.1% average loss |
| Published | New England Journal of Medicine (2021) | New England Journal of Medicine (2022) |
How Dose AI helps GLP-1 users
Dose AI is designed specifically for people on GLP-1 medications. Track your progress, nutrition, and medication — all in one place. Dose AI is a tracking tool, not a medical device.
Dose AI is a tracking and information tool, not a medical device. Always consult your healthcare provider for medical advice about your GLP-1 medication.
