GLP-1 Practices

What Are GLP-1 Medications?

A comprehensive guide to understanding GLP-1 receptor agonists, how they work, and who may benefit from these medications.

Definition and Mechanism of Action

GLP-1 receptor agonists are a class of injectable and oral medications that mimic the effects of glucagon-like peptide-1 (GLP-1), a naturally occurring incretin hormone produced in your intestines after eating. These medications bind to the same receptors as natural GLP-1 but remain active in your body for much longer.

When GLP-1 medications activate these receptors, they trigger several beneficial effects: they stimulate insulin secretion from the pancreas when blood sugar is elevated (but not when it's normal, reducing the risk of hypoglycemia), suppress glucagon release which helps lower blood sugar, slow gastric emptying so food moves more slowly through your digestive system, and act on appetite centers in the brain to reduce hunger and increase feelings of fullness.

History of GLP-1 Medications

The first GLP-1 receptor agonist, exenatide (Byetta), was approved by the FDA in 2005 for type 2 diabetes. This was based on research into the Gila monster lizard, whose saliva contains a compound similar to human GLP-1. Since then, the class has evolved significantly with longer-acting formulations.

Semaglutide, developed by Novo Nordisk, was first approved as Ozempic for type 2 diabetes in 2017. The same active ingredient was later approved at a higher dose as Wegovy for chronic weight management in 2021. Tirzepatide, a newer dual GIP/GLP-1 receptor agonist from Eli Lilly, received FDA approval as Mounjaro for type 2 diabetes in 2022 and as Zepbound for chronic weight management in 2023.

Current FDA-Approved GLP-1 Medications

Several GLP-1 medications are currently available in the United States. For detailed information about each medication, including dosing and administration, see our comprehensive GLP-1 medications guide.

  • Semaglutide: Ozempic (diabetes), Wegovy (weight management), Rybelsus (oral diabetes medication)
  • Tirzepatide: Mounjaro (diabetes), Zepbound (weight management)
  • Other GLP-1s: Trulicity (dulaglutide), Victoza (liraglutide), Byetta/Bydureon (exenatide)

How They Differ from Older Weight Loss Medications

Previous generations of weight loss medications primarily worked by stimulating the central nervous system (like phentermine) or blocking fat absorption (like orlistat). Many older medications had significant limitations including cardiovascular risks, dependency potential, or uncomfortable gastrointestinal side effects.

GLP-1 receptor agonists work through a fundamentally different mechanism that more closely mimics natural physiological processes. They have been shown in clinical trials to produce more significant and sustained weight loss while also improving cardiovascular risk factors. Some GLP-1 medications have even demonstrated cardiovascular benefits in dedicated outcomes trials.

Who May Be a Candidate

For type 2 diabetes, GLP-1 receptor agonists may be considered for adults who have not achieved adequate blood sugar control with lifestyle modifications and/or other diabetes medications.

For chronic weight management, FDA-approved GLP-1 medications are indicated for adults with a body mass index (BMI) of 30 kg/m² or greater (obesity), or BMI of 27 kg/m² or greater (overweight) with at least one weight-related health condition such as high blood pressure, type 2 diabetes, or high cholesterol.

These medications are not appropriate for everyone. They are not recommended for those with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2, those with a history of pancreatitis, or during pregnancy. Your healthcare provider can help determine if you may be a candidate.

How to Discuss with Your Doctor

If you're considering GLP-1 medications, preparation can help you have a productive conversation with your healthcare provider. Consider discussing:

  • Your health history, including any weight-related conditions
  • Previous weight management approaches you've tried
  • Your current medications and any potential interactions
  • Insurance coverage and cost considerations
  • What to expect in terms of side effects and monitoring
  • Long-term plans for maintaining results

For information on finding a provider, see our guide on how to get a GLP-1 prescription.

Frequently Asked Questions

No, GLP-1 medications are not insulin. They are a different class of medications that work by mimicking the GLP-1 hormone to stimulate insulin secretion, slow gastric emptying, and reduce appetite. Unlike insulin injections which directly add insulin to your body, GLP-1 medications help your body use its own insulin more effectively.
No, GLP-1 medications for weight management are FDA-approved for adults with a BMI of 30 or higher (obesity) or BMI of 27 or higher with at least one weight-related health condition such as type 2 diabetes, high blood pressure, or high cholesterol. A healthcare provider must evaluate your individual situation.
GLP-1 medications are typically prescribed as long-term treatments. Research suggests that stopping these medications often leads to weight regain, similar to other chronic conditions that require ongoing management. Your healthcare provider will work with you to determine the best long-term approach.
Semaglutide (Ozempic, Wegovy) is a pure GLP-1 receptor agonist. Tirzepatide (Mounjaro, Zepbound) is a dual GIP/GLP-1 receptor agonist, meaning it activates two hormone receptors. Clinical trials have shown tirzepatide may produce greater weight loss on average, though individual results vary.
GLP-1 medications are often used in combination with other diabetes medications, including metformin. However, they should generally not be combined with other GLP-1 medications or certain insulin regimens without careful medical supervision due to increased risk of low blood sugar. Your doctor will determine safe combinations.