What Is GLP-1? A Complete Guide to GLP-1 Medications

GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after you eat. It tells your pancreas to release insulin, slows how quickly food leaves your stomach, and signals fullness to your brain. GLP-1 medications mimic this hormone to lower blood sugar and curb appetite — which is why they’re now prescribed for both type 2 diabetes and weight loss.

10 min read•By Aaliyah Mallard, PharmD•Medically reviewed

What is GLP-1, exactly?

GLP-1 is a natural hormone called an incretin. Your intestines secrete it within minutes of a meal, and it does three things at once:

1
It triggers insulin release from the pancreas — but only when blood sugar is actually elevated, which is why GLP-1 medications carry a low risk of dangerous hypoglycemia on their own (Cleveland Clinic).
2
It slows gastric emptying, so food stays in your stomach longer and you feel full sooner.
3
It acts on the brain’s appetite centers, reducing hunger and food cravings (Harvard Health Publishing).

The catch — the GLP-1 your body produces breaks down within minutes. The medications in this class are agonists — engineered versions that resist that breakdown and stay active far longer, from hours to a full week.

How do GLP-1 medications work?

A GLP-1 medication doesn’t “burn fat.” It works by changing the underlying hunger and satiety signals that drive overeating:

You feel full on less food — slower stomach emptying means smaller meals satisfy.
Cravings quiet down — the drug’s action on brain appetite circuits reduces the urge to snack and the “food noise” many patients describe.
Blood sugar stabilizes — insulin rises only after meals, and the liver produces less excess glucose (American Diabetes Association).

The result in clinical trials is meaningful, sustained weight loss — but only while taking the medication, which matters (see the FAQ below).

The GLP-1 medication landscape

There are several GLP-1 receptor agonists on the market, each with two FDA-approved uses. The big ones:

Medication	Brand (diabetes)	Brand (weight loss)	Dosing	Note
Semaglutide	Ozempic	Wegovy	Weekly	The most widely known
Tirzepatide	Mounjaro	Zepbound	Weekly	Dual GIP/GLP-1 agonist — acts on two receptors
Liraglutide	Victoza	Saxenda	Daily	Older, daily injection
Dulaglutide	Trulicity	—	Weekly	Type 2 diabetes only

A precise but important distinction — tirzepatide is a dual GIP and GLP-1 receptor agonist, not a pure GLP-1 drug. In head-to-head trials it produced slightly greater weight loss than semaglutide, but both are considered first-line for obesity (FDA;NEJM SURMOUNT-1 trial).

What are GLP-1s actually used for?

Type 2 diabetes: GLP-1s were first approved to lower A1C, and they remain a cornerstone of diabetes care. They lower blood sugar with a low risk of hypoglycemia when used alone.
Weight loss / obesity: At higher doses, the same drugs are approved for chronic weight management in adults with a body mass index of 30+, or 27+ with at least one weight-related condition like high blood pressure or sleep apnea (FDA).
Beyond the scale: Emerging research shows cardiovascular benefit — semaglutide reduced major cardiovascular events in people with diabetes in the SUSTAIN-6 trial, and studies of heart and kidney outcomes are ongoing. This is one reason the class has moved from “diabetes drug” to “cardio-metabolic therapy.”

Side effects and risks

The most common side effects are gastrointestinal and tend to be worst in the first weeks: nausea, vomiting, diarrhea or constipation, abdominal pain. Most improve as the body adjusts, which is why dosing starts low and titrates up over weeks (Mayo Clinic).

Rarer but serious risks to know:

Gallbladder disease / gallstones — linked to rapid weight loss generally, not just this class.
Pancreatitis — rare; watch for severe, persistent abdominal pain.
Thyroid C-cell tumors — seen in rodents; a black-box warning means these drugs are contraindicated in anyone with a personal or family history of medullary thyroid carcinoma or MEN 2 syndrome.
Muscle loss — a portion of weight lost on GLP-1s is lean mass, so protein intake and resistance training matter.

Important: This is a summary, not medical advice. GLP-1s are prescription medications and should be started and monitored under a clinician’s supervision.

How much do GLP-1s cost?

List prices are high and vary widely. As of 2026, without insurance: semaglutide (Wegovy) roughly $1,300–$1,400 per month at list price; tirzepatide (Zepbound) roughly $1,100–$1,200 per month; liraglutide (Saxenda) roughly $1,300+ per month. Insurance coverage for weight-loss use is inconsistent — many plans cover these drugs for diabetes but not obesity — which is a major reason people ask about cheaper alternatives (GoodRx). Compounded versions have emerged at lower cost, but they are not FDA-approved and carry additional safety and consistency questions.

Who should — and shouldn’t — take GLP-1 medications

Good candidates

Adults with type 2 diabetes not well-controlled on other medications, or adults with obesity/overweight plus a weight-related condition who haven’t succeeded with lifestyle change alone.

Should avoid

Anyone with a personal or family history of medullary thyroid carcinoma or MEN 2; anyone with a history of pancreatitis; and people who are pregnant or trying to conceive (the drugs should be stopped before a planned pregnancy).

Frequently asked questions

What are GLP-1s?

GLP-1s are a class of medications that mimic the gut hormone glucagon-like peptide-1. They lower blood sugar and suppress appetite, and are approved for type 2 diabetes and — at higher doses — for weight loss. Common names include semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound).

What is known as the “poor man’s Ozempic”?

It is a nickname for berberine, an over-the-counter supplement that weakly influences some of the same metabolic pathways as GLP-1 medications. The name comes from its low cost relative to prescription GLP-1s — but it’s not the same thing: berberine is far weaker, far less studied for weight loss, and is not FDA-approved to treat diabetes or obesity.

Can you smell when someone is on Ozempic?

No. There is no scientific evidence that taking Ozempic (or any GLP-1) produces a detectable odor you could use to identify a user. Some people taking the medication report side effects like bad breath or changes in taste (“Ozempic breath”), generally tied to the gastrointestinal changes or mild dehydration — but this is inconsistent, and it doesn’t create a reliable “smell” you can detect in someone else.

Do you gain weight after stopping GLP-1?

Yes — most people do. In clinical trials, patients who stopped semaglutide regained a significant share of the weight they’d lost within a year (NEJM STEP-4 trial). GLP-1 medications suppress appetite only while active in the body; when stopped, the underlying hunger signals return. That’s why these are generally considered long-term treatments, not a short course — and why a maintenance plan matters before you start.