GLP-1 medications for weight loss: how they work and what to expect
What these medications do in the body, who they are approved for, common side effects and what happens when you stop.
By [AUTHOR NAME]Medically reviewed by [REVIEWER NAME, MD]Updated [9] min read
Key takeaways
GLP-1 medications mimic a gut hormone that helps regulate appetite and fullness.
Some are FDA-approved for chronic weight management in adults who meet specific BMI criteria.
Digestive side effects such as nausea are common, especially when the dose is increased.
They work best alongside changes to eating and activity, and weight often returns after stopping.
How do GLP-1 medications work?
GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after eating. Medications that act like it slow how quickly the stomach empties and signal fullness to the brain, which can reduce hunger and how much you eat.
Some newer medications also act on a second hormone, GIP. Your clinician will explain how the option they recommend differs from others.
Who are GLP-1 medications approved for?
Brand-name GLP-1 medications approved for weight management are generally prescribed to adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition such as high blood pressure or type 2 diabetes. A clinician makes the final call based on your full history.
People with a personal or family history of medullary thyroid cancer or MEN 2 are typically advised not to use them.
Tell your clinician if you are pregnant, planning a pregnancy or have a history of pancreatitis or gallbladder disease.
What are the common side effects?
Nausea, vomiting, diarrhea, constipation and stomach discomfort are the most commonly reported effects. They are often strongest when you start or move up a dose, which is why doses are usually increased gradually.
Contact your clinician promptly about severe stomach pain, signs of dehydration or any symptom that worries you.
Are compounded GLP-1s the same as brand-name?
Compounded versions are made by pharmacies and are not FDA-approved, which means their safety, quality and effectiveness have not been reviewed the same way. If a provider offers one, ask which pharmacy prepares it and why it is being recommended over a brand-name option.
What happens when you stop taking a GLP-1?
Studies have found that many people regain weight after stopping these medications. Talk with your clinician about a long-term plan before you start, including how you would come off treatment if you decide to.
When to talk to a clinician
Speak with a licensed clinician before starting any weight loss medication, and seek care right away for severe abdominal pain, persistent vomiting or signs of an allergic reaction.
Common questions
Results vary by medication, dose and person. In clinical trials many adults lost a meaningful share of their body weight over a year or more when medication was combined with diet and activity changes. Your clinician can explain what is realistic for you.
Sources
U.S. Food and Drug Administration. Prescribing information for FDA-approved GLP-1 weight management medications. [ADD LINK]
National Institute of Diabetes and Digestive and Kidney Diseases. Prescription medications to treat overweight and obesity. [ADD LINK]
U.S. Food and Drug Administration. Information on compounded drug products. [ADD LINK]
This article is for informational purposes only and is not medical advice. Talk to a licensed clinician before starting, stopping or changing any treatment.
