What are GLP-1 medications and how do they work?

GLP-1 medications are injectable drugs that mimic a natural hormone (GLP-1) your body produces after eating. They work by reducing appetite through brain signaling, increasing satiety after meals, slowing stomach emptying, and regulating blood sugar. This leads to an average weight loss of 15-22% of body weight in clinical trials.

What's the difference between semaglutide and tirzepatide?

Semaglutide (Wegovy, Ozempic) targets only GLP-1 receptors and produces ~15% body weight loss. Tirzepatide (Zepbound, Mounjaro) is a dual agonist that targets both GIP and GLP-1 receptors, producing ~22% body weight loss. Both are weekly injections, but tirzepatide typically produces more weight loss due to its dual mechanism.

How much weight can I expect to lose on GLP-1 medications?

Weight loss varies by medication: Semaglutide 2.4mg produces average 15% body weight loss over 68 weeks (about 33 lbs for a 220 lb person). Tirzepatide 15mg produces average 22.5% weight loss over 72 weeks. Liraglutide produces average 8% weight loss. Individual results depend on starting weight, lifestyle factors, and medication adherence.

Who qualifies for GLP-1 weight loss medications?

GLP-1 medications are FDA-approved for adults with BMI of 30+ (obesity) or BMI of 27+ (overweight) with at least one weight-related condition like type 2 diabetes, high blood pressure, high cholesterol, or sleep apnea. They work best when combined with a reduced-calorie diet and increased physical activity.

What are the common side effects of GLP-1 medications?

Most common side effects are gastrointestinal: nausea (20-44%), diarrhea (21-30%), vomiting (9-24%), and constipation (11-24%). These typically occur during dose escalation and improve over time. Starting at low doses and gradually increasing helps minimize side effects. Serious side effects are rare but include pancreatitis, gallbladder problems, and thyroid concerns.

GLP-1 Complete Guide: Everything You Need to Know in 2025

GLP-1 receptor agonists have revolutionized weight loss treatment, offering the most effective pharmacological approach to obesity with some formulations producing over 20% body weight loss in clinical trials.

What Are GLP-1 Medications?

GLP-1 (glucagon-like peptide-1) is a hormone your body naturally produces in your intestines after eating.

GLP-1 Medications Comparison

Feature	Medication	Mechanism	Dosing
Liraglutide (Saxenda)	GLP-1 only	Daily injection	~8% body weight
Semaglutide (Wegovy)	GLP-1 only	Weekly injection	~15% body weight
Tirzepatide (Mounjaro)	Dual GIP/GLP-1	Weekly injection	~22% body weight