GLP-1 basics: questions and answers

A GLP-1 medicine is a prescription drug that copies GLP-1, a hormone your gut releases after you eat. It slows how fast your stomach empties, lowers appetite through signals in the brain and helps the pancreas release insulin when blood sugar is high.

Common examples are semaglutide (Ozempic, Wegovy, Rybelsus), tirzepatide (Mounjaro, Zepbound), liraglutide (Victoza, Saxenda) and dulaglutide (Trulicity). Some are approved for type 2 diabetes, others for weight management.

GLP-1 drugs help with weight loss mainly by making you feel full sooner and less hungry between meals. They act on appetite centers in the brain and slow stomach emptying, so smaller portions feel like enough.

Eating less over weeks and months is what drives the weight change. The labels describe them as an add-on to a reduced-calorie diet and more physical activity, not a replacement. For a fuller walk-through, see how GLP-1 drugs work.

Ozempic and Wegovy contain the same medicine, semaglutide, made by Novo Nordisk, but they are approved for different uses and doses. Ozempic is approved for type 2 diabetes, with a top label dose of 2 mg weekly. Wegovy is approved for chronic weight management and heart-risk reduction, with a usual maintenance dose of 2.4 mg weekly.

Ozempic comes in a multi-dose pen, while Wegovy comes in single-dose pens. Insurance treats them differently because of those approved uses.

Yes, Mounjaro and Zepbound are the same medicine, tirzepatide from Eli Lilly, sold under two brand names. Mounjaro is approved for blood sugar control in adults with type 2 diabetes. Zepbound is approved for chronic weight management and for moderate to severe obstructive sleep apnea in adults with obesity.

Both use the same weekly dose steps, from 2.5 mg up to a label maximum of 15 mg. The brand on your prescription mostly reflects the condition being treated, which affects coverage.

Tirzepatide acts on two gut-hormone receptors, GIP and GLP-1, while semaglutide acts on GLP-1 only. Both are taken weekly as injections, and semaglutide also comes as a daily tablet.

In their main weight trials, tirzepatide 15 mg led to average loss of 20.9% at 72 weeks (SURMOUNT-1) and semaglutide 2.4 mg led to 14.9% at 68 weeks (STEP 1). These were separate trials, so the numbers are not a direct comparison. See tirzepatide vs semaglutide.

The GLP-1 medicines FDA approved for chronic weight management include Zepbound (tirzepatide), Wegovy (semaglutide injection), the Wegovy pill (oral semaglutide, approved December 2025) and Saxenda (liraglutide).

Ozempic, Mounjaro, Rybelsus, Victoza and Trulicity are approved for type 2 diabetes, not weight management, although some cause weight loss. Approved uses can change, so check the current label on DailyMed or ask a pharmacist. Our GLP-1 medicines overview lists each one.

No, Ozempic is not FDA approved for weight loss. Its label covers blood sugar control in adults with type 2 diabetes, plus heart and kidney risk reduction in certain adults with type 2 diabetes.

Wegovy contains the same medicine, semaglutide, and is the version approved for chronic weight management. Prescribers can legally write Ozempic off-label, but insurers often deny coverage without a diabetes diagnosis. More context: is Ozempic a weight-loss drug.

Adults usually qualify for a weight-management GLP-1 if they have a BMI of 30 or higher, or a BMI of 27 or higher with at least one weight-related condition such as high blood pressure, type 2 diabetes or high cholesterol. That is the standard wording on the Zepbound and Wegovy labels.

A prescriber also checks your history for reasons not to use one. Insurers may add their own rules. If you want a professional opinion, a clinician can reach out through find a clinician.

Yes, several GLP-1 medicines are approved for people without diabetes. Zepbound, Wegovy, the Wegovy pill and Saxenda are approved for chronic weight management in adults with obesity, or overweight plus a weight-related condition, whether or not they have diabetes.

The big weight trials, STEP 1 for Wegovy and SURMOUNT-1 for Zepbound, enrolled adults without diabetes. Diabetes brands like Ozempic and Mounjaro are the ones that require a type 2 diabetes diagnosis for on-label use.

Some can. Wegovy is approved for chronic weight management in children 12 and older with obesity, and Saxenda is approved for children 12 to 17 with obesity who weigh more than 132 lb (60 kg). Zepbound is approved for adults.

For type 2 diabetes, Victoza and Trulicity are approved in people 10 and older. Decisions for teens are made with a pediatric clinician who can weigh growth, nutrition and family history alongside the medicine.

You should not take a GLP-1 medicine if you or a family member has had medullary thyroid carcinoma (MTC), if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), or if you have had a serious allergic reaction to the drug. These are the label contraindications.

Labels also urge caution with a history of pancreatitis, severe stomach problems such as gastroparesis, diabetic eye disease and pregnancy. Share your full medical history with your prescriber before starting.

Many people notice less appetite within the first few weeks, but steady weight loss builds over months. Doses start low and rise every few weeks, so the full effect usually comes after you reach a maintenance dose.

Semaglutide lasts about a week in the body, so steady levels take 4 to 5 weeks at each dose. In the STEP 1 and SURMOUNT-1 trials, weight kept falling for well over a year. You can sketch a projection with the GLP-1 weight-loss calculator.

In the SURMOUNT-1 trial, adults without diabetes lost an average of 15.0% of body weight on Zepbound 5 mg, 19.5% on 10 mg and 20.9% on 15 mg over 72 weeks, compared with 3.1% on placebo.

At 15 mg, about 9 in 10 people lost at least 5% of their weight. Averages hide a wide range, and results depend on dose, adherence, diet and health conditions. See Zepbound weight loss results.

In the STEP 1 trial, adults without diabetes lost an average of 14.9% of body weight on Wegovy 2.4 mg over 68 weeks, compared with 2.4% on placebo.

About 86% lost at least 5%, 69% lost at least 10% and about a third lost at least 20%. Your result may differ depending on dose, how long you stay on it and your eating and activity habits. More detail on Wegovy weight loss.

Slow early progress is common because the first doses are starting doses, not maintenance doses. Weight loss usually picks up after several dose steps.

Other factors include eating more calorie-dense foods, drinking calories, other medicines that cause weight gain, thyroid or hormone issues, poor sleep and missed doses. Some people simply respond less. The Saxenda label, for example, says to stop if you have not lost at least 4% of body weight after 16 weeks. Review your progress with your prescriber before changing anything.

No, response varies a lot from person to person. In STEP 1, 86% of people on Wegovy 2.4 mg lost at least 5% of their weight, which also means some did not.

Genetics, dose, side effects that limit dose increases, diabetes status and other medicines can all affect results. People with type 2 diabetes tend to lose somewhat less weight than people without it. If you are not responding after reaching a maintenance dose, your prescriber may consider a different medicine or approach.

Yes. Every weight-management GLP-1 label says the medicine is used with a reduced-calorie diet and increased physical activity. In the trials, participants also got lifestyle counseling.

The medicine makes eating less easier, but food quality still matters. Enough protein and regular strength training help protect muscle while you lose weight, and the habits you build now help if you ever lower your dose or stop. A gentle start, like daily walks, counts.

GLP-1 medicines for weight are approved for chronic weight management, which means they are designed for long-term use, much like blood pressure medicine. There is no set end date on the labels.

Trials show weight tends to return after stopping, so many people stay on a maintenance dose for years. Some later try a lower dose or stop with close follow-up. How long you stay on it is a decision to make with your prescriber based on your results, side effects and cost.

When you stop, appetite usually returns within weeks and much of the lost weight tends to come back over the following year. Improvements in blood pressure, blood sugar and cholesterol may also fade.

In the STEP 1 extension, people regained about two-thirds of the weight they had lost within one year of stopping semaglutide. Planning ahead with your prescriber helps. Our guide to stopping a GLP-1 covers what to expect.

Most people regain a good part of the weight after stopping tirzepatide. In the SURMOUNT-4 trial, adults who switched to placebo after 36 weeks on tirzepatide regained about 14% of their body weight over the next year, while those who stayed on it lost about 5.5% more.

Results vary, and strong habits around protein, strength training and portions may soften regain. Talk with your prescriber before stopping, since restarting later means stepping back up from a low dose.

Talk with your prescriber before stopping. The labels do not require a taper, but your prescriber may suggest lowering the dose gradually or setting up closer follow-up, especially if you have diabetes and your blood sugar plan needs to change.

Expect appetite to return over a few weeks. Keep weighing yourself regularly, keep protein and strength training in place and agree on a plan for what to do if weight starts climbing. A clinician can reach out through find a clinician if you need one.

It depends on the medicine. Semaglutide injections have a half-life of about 1 week, tirzepatide and dulaglutide about 5 days, and liraglutide about 13 hours.

A medicine is mostly cleared after about five half-lives, so weekly semaglutide can linger for around 5 weeks. That is why the Wegovy and Ozempic labels advise stopping at least 2 months before a planned pregnancy, and why you should tell your surgical team about a GLP-1 even if you skipped a dose.

Yes. The Wegovy pill, a daily oral semaglutide tablet, was FDA approved in December 2025 for chronic weight management. Rybelsus is an older semaglutide tablet approved only for type 2 diabetes.

In the OASIS 4 trial, people on oral semaglutide 25 mg lost about 13.6% of body weight at 64 weeks vs 2.2% on placebo. It must be taken on an empty stomach with a small sip of water. See the Wegovy pill page for details.

No FDA-approved generic semaglutide or tirzepatide was available in the US as of our last review. Generic liraglutide, the medicine in Victoza and Saxenda, is on the market and is usually cheaper than the brands.

Compounded semaglutide and tirzepatide are not generics. They are not FDA approved and have not been reviewed by the FDA for safety, effectiveness or quality. Check FDA.gov for any new generic approvals before assuming one exists.

Saxenda is liraglutide, an older GLP-1 approved for weight management in December 2014. It is injected once daily, while Wegovy is injected once weekly.

Saxenda tends to produce less weight loss. In its main trial, average loss was 8.0% at 56 weeks vs 2.6% on placebo, compared with 14.9% for Wegovy in STEP 1. Generic liraglutide is now sold, which can make it a lower-cost option. Learn more on the Saxenda page.

No, a GLP-1 medicine is not insulin. GLP-1 drugs help your own pancreas release more insulin when blood sugar is high, and they slow stomach emptying and lower appetite. Insulin replaces or adds to the hormone directly.

Because GLP-1s mostly act when blood sugar is high, they rarely cause low blood sugar on their own. The risk rises when they are combined with insulin or a sulfonylurea, so your prescriber may lower those doses.

Yes. In December 2024 the FDA added moderate to severe obstructive sleep apnea in adults with obesity to the Zepbound label. The label doses for sleep apnea are 10 mg or 15 mg once weekly.

Zepbound does not replace CPAP or other sleep apnea treatment on its own. Your sleep specialist decides how it fits your plan. Read more in our guide to GLP-1 medicines and sleep apnea.

Yes, for certain people. In March 2024 the FDA approved Wegovy to reduce the risk of heart attack, stroke and cardiovascular death in adults with established heart disease and either obesity or overweight.

Ozempic and Victoza carry similar heart-risk indications for adults with type 2 diabetes and heart disease. This benefit was shown in specific trial populations, so ask your cardiologist or prescriber whether it applies to you. The heart indication also matters for Medicare coverage.

Wegovy was approved in 2025 for noncirrhotic MASH, a form of fatty liver disease with liver scarring, in adults. It is used alongside diet and exercise.

Weight loss in general tends to reduce liver fat, so other GLP-1 medicines may help indirectly, but only Wegovy carries this approved use as of our last review. If you have been told you have fatty liver, your liver specialist or primary care clinician can tell you whether treatment fits your stage of disease.

A plateau is expected. As you lose weight, your body burns fewer calories, and the gap between what you eat and what you burn narrows. In the STEP 1 and SURMOUNT-1 trials, average weight loss leveled off after about a year to a year and a half.

If you plateau early, check portions, protein, drinks and activity, and talk with your prescriber about whether you are on your maintenance dose. Our guide to the weight-loss plateau has next steps.