What Is a GLP-1? How These Medicines Work, From the Labels

Short answer: GLP-1 stands for glucagon-like peptide-1, a hormone the body makes. “GLP-1 medicines” are prescription drugs that act on the GLP-1 receptor, which is why the Wegovy® label calls semaglutide a GLP-1 receptor agonist. They are prescribed for type 2 diabetes, for weight reduction, and for some other conditions, depending on the medicine. Your prescriber decides whether one is right for you.

What does GLP-1 stand for?

GLP-1 is short for glucagon-like peptide-1. The Wegovy label describes it as “a physiological regulator of appetite and caloric intake,” meaning the body’s own GLP-1 is part of how appetite and eating are regulated.

What is a GLP-1 medicine?

A GLP-1 medicine is a drug designed to act on the same receptor as the body’s GLP-1. The Wegovy label says semaglutide “is a GLP-1 analogue with 94% sequence homology to human GLP-1” and “acts as a GLP-1 receptor agonist.” An agonist is a drug that activates a receptor. MedlinePlus, the NIH patient-information site, puts semaglutide in “a class of medications called incretin mimetics.”

How do GLP-1 medicines work?

The Wegovy label says in its pharmacodynamics section that “semaglutide decreases calorie intake.” MedlinePlus describes semaglutide as helping the pancreas release insulin when blood sugar is high and slowing stomach emptying. Exactly how a medicine affects you depends on the medicine and on you, so ask your prescriber.

Is Zepbound a GLP-1 medicine too?

Partly. The Zepbound® label says: “Tirzepatide is a GIP receptor and GLP-1 receptor agonist.” That means it acts on the receptor for another gut hormone, GIP, in addition to the GLP-1 receptor. People often group it with GLP-1 medicines in everyday conversation.

What are GLP-1 medicines prescribed for?

The labels list specific uses, always alongside a reduced-calorie diet and increased physical activity (for the weight and sleep apnea uses):

Medicine	Uses listed in Section 1 of the label (DailyMed)
Wegovy (semaglutide)	Reducing the risk of major cardiovascular events in certain adults; reducing excess body weight and maintaining weight reduction in certain adults and in pediatric patients 12 and older with obesity; treating noncirrhotic MASH with moderate to advanced liver fibrosis in adults
Zepbound (tirzepatide)	Reducing excess body weight and maintaining weight reduction in adults with obesity or overweight; treating moderate to severe obstructive sleep apnea in adults with obesity

MedlinePlus lists semaglutide injection (Ozempic® and Wegovy) as prescribed “to control blood sugar levels in certain patients with type 2 diabetes” and “to assist with weight loss in certain people who are obese or overweight and have weight-related medical problems.” Eligibility details are in each label and are for your prescriber to apply.

How are they taken?

MedlinePlus says semaglutide is “injected once a week” under the skin with a prefilled pen. Your prescriber and the Instructions for Use that come with your pen explain how. For where on the body the labels say to inject, see GLP-1 injection sites.

What side effects should you know about?

Stomach and bowel effects such as nausea, diarrhea, vomiting and constipation were the most common in trials, and the labels list serious warnings too. The label figures are in GLP-1 side effects: a plain-language guide. One more point from the Zepbound label: using it together with other tirzepatide products or any GLP-1 receptor agonist is not recommended.

When to call your doctor

Call your prescriber with any question about whether a GLP-1 medicine is right for you, how to take it, or what you are feeling. Call immediately or get emergency medical treatment for the serious symptoms MedlinePlus lists, such as a lump or swelling in the neck, hoarseness, difficulty swallowing, shortness of breath, or ongoing pain that starts in the upper left or middle of the stomach and may spread to the back.

Weeko, a shot tracker coming to iPhone and Android, is being built to help people keep a simple log of their shots. It is a logbook, not medical guidance.