The short answer
GLP-1 drugs are prescription medicines that copy a natural gut hormone to lower blood sugar, slow digestion and quiet appetite. In the US, the main GLP-1 drugs are Ozempic, Wegovy, Rybelsus, Mounjaro, Zepbound and the new Foundayo pill. Most side effects are stomach-related, and the weight usually comes back if you stop.
- Best-known names: Wegovy and Ozempic (semaglutide), Zepbound and Mounjaro (tirzepatide), Foundayo (orforglipron).
- Typical weight loss in trials: about 15% on Wegovy injection and up to about 21% on the top dose of Zepbound over 68 to 72 weeks.
- Most common side effects: nausea, diarrhea, vomiting, constipation and stomach pain.
- Cost without insurance: manufacturer cash prices now start at $149 a month for the lowest pill doses, as of October 2026.
- Medicare: eligible Part D enrollees can pay $50 a month through the Medicare GLP-1 Bridge (July 2026 to December 2027).
14.9%
Average weight loss on Wegovy 2.4 mg in STEP 1
20.9%
Average weight loss on Zepbound 15 mg in SURMOUNT-1
20%
Lower risk of heart attack, stroke or CV death in SELECT
$50
Monthly Medicare GLP-1 Bridge copay
In this article
Ozempic, Wegovy, Mounjaro and Zepbound have gone from niche diabetes treatments to household names. Meanwhile, 2026 added two daily pills, a $50 Medicare option and a firm FDA line against copycat compounded versions. As a result, a lot of older advice about GLP-1 drugs is now out of date.
This guide explains what GLP-1 drugs are, which ones the FDA has approved, what the trials actually showed, the side effects listed on the official labels, and what they cost today. If you already know you want one and are choosing between brands, our head-to-head Ozempic vs Wegovy vs Zepbound comparison goes deeper on that decision.
What Are GLP-1 Drugs?
GLP-1 drugs are medicines that act like glucagon-like peptide-1 (GLP-1), a hormone your gut releases after you eat. Doctors also call them GLP-1 receptor agonists, meaning drugs that switch on the same receptor the natural hormone uses.
According to the Wegovy prescribing information, GLP-1 is a natural regulator of appetite and calorie intake, and its receptors sit in several brain areas that control hunger. The first drugs in the class treated type 2 diabetes. However, researchers saw that patients also lost weight, so manufacturers developed higher-dose versions specifically for obesity.
Today the term covers two groups. First, there are pure GLP-1 drugs such as semaglutide (Ozempic, Wegovy, Rybelsus) and liraglutide (Victoza, Saxenda). Second, there are dual-action drugs such as tirzepatide (Mounjaro, Zepbound), which also mimics a second gut hormone called GIP, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
How Do GLP-1 Drugs Work in Your Body?
GLP-1 drugs work in three places at once: the pancreas, the stomach and the brain. Together, those effects lower blood sugar and make you feel full sooner and for longer.
- Pancreas: the drug prompts insulin release and cuts glucagon only when blood sugar is high. The label calls this a glucose-dependent effect, which is why GLP-1 drugs alone rarely cause dangerous lows.
- Stomach: semaglutide delays gastric emptying, so food leaves the stomach more slowly. That slower pace also explains much of the nausea people feel early on.
- Brain: the drugs act on brain regions that regulate appetite and food intake, so many people report fewer cravings and less constant thinking about food.
In addition, tirzepatide adds GIP activity on top of GLP-1. That second hormone is one reason Zepbound produced larger average weight loss than Wegovy in separate trials, although the two were tested in different studies.
Which GLP-1 Drugs Are FDA-Approved?
The FDA has approved several GLP-1 drugs, and the main difference between them is the ingredient, the dose and whether the label covers diabetes or weight loss. Below are the brands most people in the US will hear about in 2026.
| Brand | Ingredient | Main FDA use | How you take it |
|---|---|---|---|
| Ozempic | Semaglutide | Type 2 diabetes; also kidney and heart risk reduction in some adults with diabetes | Weekly injection |
| Rybelsus | Semaglutide | Type 2 diabetes | Daily tablet |
| Wegovy | Semaglutide | Weight loss, heart risk reduction, MASH liver disease | Weekly injection (2.4 mg; 7.2 mg Wegovy HD) |
| Wegovy pill | Semaglutide 25 mg | Weight loss and heart risk reduction | Daily tablet on an empty stomach |
| Mounjaro | Tirzepatide (GLP-1 + GIP) | Type 2 diabetes | Weekly injection |
| Zepbound | Tirzepatide (GLP-1 + GIP) | Weight loss; obstructive sleep apnea in adults with obesity | Weekly injection (pen, KwikPen or vial) |
| Foundayo | Orforglipron | Weight loss | Daily pill, no food or water rules |
| Victoza / Saxenda | Liraglutide | Diabetes / weight loss (generics approved) | Daily injection |
| Trulicity | Dulaglutide | Type 2 diabetes | Weekly injection |
A few of these changed recently. For example, the FDA approved the Wegovy pill in December 2025, and Novo Nordisk launched it in January 2026. Then, on April 1, 2026, the FDA approved Eli Lilly’s Foundayo, a non-peptide pill that you can take at any time of day without food or water restrictions. Earlier, in December 2024, Zepbound became the first FDA-approved medicine for obstructive sleep apnea in adults with obesity.
GLP-1 drugs in pill form vs injections
Pills suit people who dislike needles, but they come with trade-offs. The Wegovy pill must go down on an empty stomach, and you then wait 30 minutes before eating. In contrast, Foundayo has no timing rules. Meanwhile, weekly injections still post the highest average weight loss in trials, so the right choice depends on your goals and your doctor’s advice.
Notably, some older names have left the market. AstraZeneca discontinued Byetta and Bydureon BCise (exenatide) in the US in late 2024 for business reasons, so you are unlikely to be offered them now.
How Much Weight Can You Lose?
In large trials, people on these medicines lost roughly 12% to 21% of their body weight on average over about 16 to 18 months, compared with 2% to 3% on placebo. Results vary a lot from person to person, though, and every trial combined the drug with diet and exercise advice.
| Drug (trial) | Length | Average weight loss | Placebo |
|---|---|---|---|
| Wegovy injection 2.4 mg (STEP 1) | 68 weeks | 14.9% | 2.4% |
| Zepbound 5 mg (SURMOUNT-1) | 72 weeks | 15.0% | 3.1% |
| Zepbound 15 mg (SURMOUNT-1) | 72 weeks | 20.9% | 3.1% |
| Wegovy pill 25 mg (OASIS 4, on treatment) | 64 weeks | 16.6% | 2.7% |
| Foundayo, highest trial dose (ATTAIN-1) | 72 weeks | 12.4% | 0.9% |
Put another way, STEP 1 found that 86.4% of people on semaglutide lost at least 5% of their weight, versus 31.5% on placebo. Similarly, in SURMOUNT-1, 57% of people on the 15 mg tirzepatide dose lost 20% or more. That said, these are averages, and some people lose much less.
Do GLP-1 drugs help your heart?
Yes, for some people. In the SELECT trial of 17,604 adults with heart disease and overweight but no diabetes, semaglutide 2.4 mg cut the combined risk of heart-related death, heart attack and stroke by 20% versus placebo (6.5% vs 8.0% of patients). Consequently, Wegovy now carries an FDA indication for cardiovascular risk reduction.
Pro tip. Strength training and enough protein help protect muscle while you lose weight on any program. Our guide to HIIT and Zone 2 cardio for belly fat covers the exercise side.
What Are the Side Effects?
The most common side effects of GLP-1 drugs are stomach and gut problems: nausea, diarrhea, vomiting, constipation and abdominal pain. They usually show up when you start or raise the dose, and for most people they ease with time.
Common GLP-1 drugs side effects (from the Wegovy label)
| Side effect | Wegovy 2.4 mg | Placebo |
|---|---|---|
| Nausea | 44% | 16% |
| Diarrhea | 30% | 16% |
| Vomiting | 24% | 6% |
| Constipation | 24% | 11% |
| Abdominal pain | 20% | 10% |
| Headache | 14% | 10% |
| Fatigue | 11% | 5% |
| Dizziness | 8% | 4% |
| Hair loss | 3% | 1% |
In STEP 1, only 4.5% of people on semaglutide quit because of gut side effects, versus 0.8% on placebo. Similarly, the FDA lists nausea, diarrhea, vomiting, constipation, injection site reactions, burping, hair loss and reflux among the side effects Zepbound can cause.
Serious but less common risks
Because these are real prescription drugs, the official labels list several serious warnings. The Wegovy prescribing information includes the following:
- Thyroid C-cell tumors (boxed warning): semaglutide caused these tumors in rodents; it is unknown whether it does in humans. People with a personal or family history of medullary thyroid cancer or MEN 2 should not use it.
- Acute pancreatitis: severe, ongoing belly pain that may spread to the back needs urgent care.
- Gallbladder disease: gallstones and gallbladder inflammation can occur.
- Kidney injury: mostly linked to dehydration from vomiting or diarrhea.
- Low blood sugar: the risk rises if you also take insulin or a sulfonylurea.
- Diabetic eye complications in people with type 2 diabetes, plus a faster heart rate.
- Anesthesia: slower stomach emptying raises the risk of inhaling stomach contents during surgery, so always tell your surgical team.
Vision, mood and other GLP-1 questions
Two safety topics shifted recently. First, Europe’s drug regulator concluded in June 2025 that NAION, a sudden loss of vision in one eye, is a very rare side effect of semaglutide, affecting up to 1 in 10,000 users. Second, in January 2026 the FDA asked makers of Wegovy, Zepbound and Saxenda to remove suicidal-thought warnings after a review of 91 trials found no such risk, and the current Wegovy label shows that section removed.
Watch out. Call your doctor right away if you have sudden vision loss, severe belly pain, signs of an allergic reaction, a lump in your neck or trouble swallowing while on any GLP-1 drug.
What Happens When You Stop?
Most people regain much of the weight after they stop a GLP-1 drug. Obesity behaves like a chronic condition, so the effect generally lasts only as long as the treatment does.
The STEP 4 trial tested this directly. After 20 weeks on semaglutide, people who switched to placebo regained 6.9% of their body weight over the next 48 weeks, while those who stayed on the drug lost a further 7.9%. Likewise, NIDDK notes that you will probably regain some weight after stopping, and that doctors may advise staying on a medicine that works indefinitely.
Still, there is a practical rule on the other side. NIDDK says that if you have not lost at least 5% of your starting weight after 12 weeks on the full dose, your provider will likely suggest stopping.
How Much Do GLP-1 Drugs Cost in 2026?
Without insurance, these medicines bought directly from the manufacturer cost about $149 to $699 a month as of October 2026, depending on the brand and dose. With coverage, many people pay far less, and Medicare now has a $50 option for some enrollees.
| Drug | Self-pay price (manufacturer) | Notes |
|---|---|---|
| Wegovy pill | $149 (1.5 mg), $199 (4 mg), $299 (9 mg and 25 mg) | NovoCare Pharmacy, per month |
| Wegovy injection | $349 for most doses; $399 for Wegovy HD 7.2 mg | $199 for first 2 fills of starter doses through Dec 31, 2026 |
| Zepbound | $299 (2.5 mg), $399 (5 mg), $449 (7.5 to 15 mg) | LillyDirect; higher doses cost $499 to $699 if not refilled within 45 days |
| Foundayo | $149 (0.8 mg and 2.5 mg), $199 (5.5 mg), $299 (9 mg and up) | LillyDirect; promo prices through Dec 31, 2026; 45-day refill rule on top doses |
For current figures, check NovoCare’s Wegovy pricing page, LillyDirect for Zepbound and LillyDirect for Foundayo. In addition, the federal TrumpRx.gov site lists the same cash offers, including Ozempic at $199 a month, as of October 2026.
Medicare GLP-1 Bridge: $50 a month
The Medicare GLP-1 Bridge is a CMS demonstration that runs from July 1, 2026, through December 31, 2027. Eligible Part D enrollees pay a flat $50 copay, although that amount does not count toward the deductible or the yearly out-of-pocket cap, and Extra Help does not apply.
- Covered drugs: Foundayo, Wegovy injection and tablets, and the Zepbound KwikPen only.
- Who qualifies: adults with a BMI of 35 or higher; a BMI of 30 or higher plus heart failure with preserved ejection fraction, uncontrolled high blood pressure or stage 3a+ kidney disease; or a BMI of 27 or higher plus prediabetes, a past heart attack or stroke, or symptomatic peripheral artery disease.
- Not through the Bridge: people with type 2 diabetes, moderate-to-severe sleep apnea or MASH go through their regular Part D plan instead.
- How to start: your prescriber requests prior authorization, and you can check details at Medicare.gov/glp1bridge or call 1-800-MEDICARE.
Full criteria appear on the CMS provider page. Meanwhile, private insurance still varies widely, and plans more often cover the diabetes versions than the weight-loss versions. Commercially insured patients can also use maker savings cards that lower costs to as little as $25 a month when the plan covers the drug.
Are Compounded GLP-1s Still an Option?
Compounded GLP-1s are now far harder to get legally, and the FDA warns against most of them. The shortages that once allowed mass copies of semaglutide and tirzepatide have ended, and the agency has been sending warning letters to telehealth sellers throughout 2026.
On April 30, 2026, the FDA proposed excluding semaglutide, tirzepatide and liraglutide from the list that lets outsourcing facilities compound from bulk ingredients, with comments open until June 29, 2026. As of mid-October 2026, we found no announcement of a final decision. Furthermore, the FDA’s safety page reports 990 adverse event reports tied to compounded semaglutide and more than 730 tied to compounded tirzepatide as of May 31, 2026.
Watch out. Be wary of online sellers offering deep discounts, no real medical screening, or claims that a compounded product is FDA-approved. The FDA does not approve compounded drugs.
Who Qualifies for a GLP-1 Prescription?
In general, you may qualify for a weight-loss GLP-1 drug if you are an adult 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. Those thresholds match the NIDDK guidance and the populations in the main trials.
Some medicines also cover teens. For example, Wegovy injection is approved for patients 12 and older with obesity. On the other hand, the labels say people with a history of medullary thyroid cancer or MEN 2 should not use semaglutide, and NIDDK advises against these drugs during pregnancy or when planning one.
Pro tip. Bring a list of your other medicines to the appointment. GLP-1 drugs slow stomach emptying, which can change how some oral medicines are absorbed.
Our verdict
GLP-1 drugs are the most effective weight-loss medicines available today, and the 2026 pills and price cuts have made them easier to reach. However, they are long-term treatments with real side effects, and the weight tends to return when you stop.
So the best next step is a frank talk with your doctor about your health goals, your insurance or Medicare options, and whether an injection or a pill fits your life. Above all, stick with FDA-approved products from licensed pharmacies.
Frequently Asked Questions
What are GLP-1 drugs?
GLP-1 drugs are prescription medicines that mimic glucagon-like peptide-1, a hormone your gut releases after eating. They help the pancreas release insulin when blood sugar is high, slow how fast your stomach empties, and act on brain areas that control appetite. Examples include Ozempic, Wegovy, Rybelsus, Mounjaro, Zepbound and the Foundayo pill. Doctors use them for type 2 diabetes, weight loss and, for some brands, heart and sleep apnea risks.
What is the most common side effect of GLP-1 drugs?
Nausea is the most common side effect. On the Wegovy label, 44% of adults on the 2.4 mg dose reported nausea versus 16% on placebo. Diarrhea, vomiting, constipation and stomach pain follow. These effects usually appear when you start or increase the dose and often fade over several weeks. Tell your doctor if symptoms are severe, because vomiting and diarrhea can cause dehydration and kidney problems.
Which GLP-1 drug causes the most weight loss?
In separate trials, tirzepatide (Zepbound) produced the largest average weight loss, about 20.9% at the 15 mg dose over 72 weeks. Semaglutide 2.4 mg (Wegovy) averaged about 14.9% over 68 weeks. However, these were different studies, and individual results vary widely. Your doctor will weigh effectiveness against side effects, cost, coverage and your other health conditions before recommending one.
Does Medicare cover GLP-1 drugs for weight loss?
Partly. Through the Medicare GLP-1 Bridge, which runs from July 1, 2026, to December 31, 2027, eligible Part D enrollees pay a $50 monthly copay for Wegovy, Foundayo or the Zepbound KwikPen. You need to meet BMI and health criteria, and your prescriber must request prior authorization. People with type 2 diabetes usually get GLP-1 coverage through their regular Part D plan instead.
Is there a GLP-1 pill instead of a shot?
Yes. The FDA approved the Wegovy pill, a daily 25 mg semaglutide tablet, in December 2025, and Foundayo, a daily orforglipron pill from Eli Lilly, on April 1, 2026. Rybelsus is an older semaglutide tablet for type 2 diabetes. The Wegovy pill must be taken on an empty stomach, while Foundayo has no food or water rules. Self-pay prices start at $149 a month.
Do you regain weight after stopping GLP-1 drugs?
Most people do. In the STEP 4 trial, people who switched from semaglutide to placebo regained 6.9% of their body weight over 48 weeks, while those who continued lost more. Because of this, doctors often treat obesity as a long-term condition and may suggest staying on a drug that works. Diet, exercise and sleep habits can help limit regain, so plan any change with your doctor.
Disclaimer: This article is for general information only and is not medical advice. GLP-1 drugs are prescription medicines. Talk to your doctor or pharmacist before starting, stopping or changing any medication, and do not change doses on your own.
