What Are GLP-1 Receptor Agonists?
A deep dive into the science behind one of the most important drug classes in modern medicine.
Overview
GLP-1 (glucagon-like peptide-1) receptor agonists are a class of medications that mimic the action of the naturally occurring incretin hormone GLP-1. These drugs were originally developed to treat type 2 diabetes but have since demonstrated remarkable efficacy for chronic weight management and cardiovascular risk reduction.
How They Work
Stimulate Insulin Secretion
GLP-1 receptor agonists enhance glucose-dependent insulin secretion from pancreatic beta cells. This means they help your body release insulin when blood sugar is high, but not when it's already normal — reducing the risk of hypoglycemia.
Suppress Glucagon
These medications suppress the release of glucagon, a hormone that raises blood sugar. By reducing glucagon, GLP-1 drugs help prevent excessive glucose production by the liver.
Slow Gastric Emptying
GLP-1 receptor agonists slow the rate at which food moves from the stomach to the small intestine. This contributes to feeling fuller for longer after meals and helps reduce post-meal blood sugar spikes.
Reduce Appetite
These drugs act on appetite centers in the brain (hypothalamus) to reduce hunger and increase feelings of satiety. This is a primary mechanism behind their effectiveness for weight loss.
Types of GLP-1 Medications
GLP-1 Receptor Agonists
Traditional GLP-1 receptor agonists target only the GLP-1 receptor. These include semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Victoza, Saxenda), and dulaglutide (Trulicity). They are available as weekly injections or, in the case of Rybelsus, a daily oral tablet.
Dual GIP/GLP-1 Receptor Agonists
Tirzepatide (Mounjaro, Zepbound) is the first dual GIP/GLP-1 receptor agonist. In addition to activating the GLP-1 receptor, it also activates the GIP (glucose-dependent insulinotropic polypeptide) receptor. This dual action has shown enhanced efficacy for both blood sugar control and weight loss in clinical trials.
FDA-Approved Uses
Type 2 Diabetes
Most GLP-1 receptor agonists are approved as adjuncts to diet and exercise for improving glycemic control in adults with type 2 diabetes.
Chronic Weight Management
Wegovy (semaglutide 2.4mg) and Zepbound (tirzepatide) are approved for chronic weight management in adults with obesity (BMI ≥30) or overweight (BMI ≥27) with at least one weight-related comorbidity.
Cardiovascular Risk Reduction
Some GLP-1 drugs, including semaglutide and dulaglutide, have demonstrated cardiovascular benefits and carry indications for reducing the risk of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease.
Medical Disclaimer
This information is provided for educational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting, stopping, or changing any medication. Individual results may vary.