Ozempic, Wegovy, Mounjaro, and Zepbound have brought widespread attention to GLP-1 medications, a group of prescription drugs used in the management of type 2 diabetes and obesity that work by regulating blood sugar, appetite, and digestion. This guide explains what distinguishes one GLP-1 medication from another, how they work, their safety considerations, and what to know about FDA-approved and compounded products.
- GLP-1 medications regulate appetite, slow stomach emptying, and improve blood sugar control — mechanisms that help manage type 2 diabetes, obesity, and certain related conditions.
- Brand names such as Ozempic, Wegovy, Mounjaro, and Zepbound are not interchangeable. They differ in their FDA-approved uses and prescribing information.
- Most GLP-1 side effects affect the digestive system and improve over time, but these medications also carry serious risks and contraindications that require ongoing medical supervision.
- Compounded GLP-1 medications are not FDA-approved and are not reviewed by the FDA for safety, effectiveness, or manufacturing quality before they are dispensed.
- GLP-1 medications are most effective when used as part of a long-term treatment plan that includes nutrition, physical activity, and regular clinical follow-up.
What are GLP-1 medications?
GLP-1 medications, also known as GLP-1 receptor agonists, are a class of prescription medicines that mimic the actions of glucagon-like peptide-1 (GLP-1), a hormone naturally released after eating that helps regulate blood sugar, appetite, and digestion. Per FDA-approved labeling, medications in this class are approved for different uses, including type 2 diabetes and chronic weight management in eligible adults with obesity or overweight and a weight-related medical condition. The American Diabetes Association's Standards of Care in Diabetes (2026) recommends GLP-1 receptor agonists for eligible adults as part of comprehensive diabetes care, alongside nutrition, physical activity, and other lifestyle measures.1
How GLP-1s work in plain English
GLP-1 medications work by acting on the body's natural systems that regulate appetite, digestion, and blood sugar. As Moiz et al. (2025) explained, GLP-1 medications do not speed up metabolism or force the body to burn fat.2 Instead, they make it easier to eat less by reducing hunger and improving fullness.
In the brain, GLP-1 medications influence areas that help regulate appetite so that you feel satisfied sooner during meals and stay full longer afterward, making it easier to reduce calorie intake. In the digestive system, they slow the rate at which food leaves the stomach. Food remains in the stomach longer, which helps extend feelings of fullness but can also contribute to nausea, especially when treatment begins or the dose is increased.
They also improve blood sugar regulation by increasing insulin release when blood glucose is elevated and reducing glucagon, a hormone that raises blood sugar. These effects help improve glucose control while carrying a low risk of hypoglycemia. This combination of reduced hunger, earlier fullness, slower digestion, and improved blood sugar regulation helps explain why these medications can support meaningful weight loss in appropriate patients when used alongside nutrition, physical activity, and ongoing medical care.
Why GLP-1s changed obesity and metabolic care
Popoviciu et al. (2023) explained that obesity is now recognized as a chronic disease associated with metabolic dysfunction and an increased risk of conditions including type 2 diabetes, hypertension, and cardiovascular disease.3 This understanding has reshaped obesity care, expanding treatment beyond nutrition and lifestyle measures to include evidence-based medications for patients.
GLP-1 receptor agonists were originally developed to treat type 2 diabetes before their role in chronic weight management became established through clinical research. Today, they form part of a broader approach to obesity and metabolic care, used alongside nutrition, physical activity, and behavioral support as part of comprehensive obesity and metabolic care.
Semaglutide, tirzepatide, and brand names
Semaglutide and tirzepatide are active ingredients, while products such as Ozempic, Wegovy, Mounjaro, and Zepbound are brand names. Each brand has its own FDA-approved indications, dosing, and prescribing information. Even when two products contain the same active ingredient, they are approved for different uses and should not be considered interchangeable without guidance from a healthcare professional.
FDA-approved indications can change. The table below reflects U.S. prescribing information available as of July 2026.
| Brand | Active ingredient | FDA-approved indication |
|---|---|---|
| Ozempic | Semaglutide | Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes; reduce the risk of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease; reduce the risk of sustained eGFR decline, end-stage kidney disease, and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.4 |
| Wegovy | Semaglutide | Reducing MACE risk in adults with CVD and obesity/overweight; chronic weight management in adults and pediatrics (12+) with obesity, or overweight with comorbid conditions; treatment of noncirrhotic MASH with moderate-to-advanced fibrosis in adults.5 |
| Mounjaro | Tirzepatide | Improve glycemic control in adults and children aged 10 years and older with type 2 diabetes.6 |
| Zepbound | Tirzepatide | Adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with obesity or adults with overweight and at least one weight-related comorbid condition; treatment of moderate to severe obstructive sleep apnea in adults with obesity.7 |
Who can be a candidate for GLP-1 medication?
Eligibility for GLP-1 medication begins with a clinical evaluation that considers body mass index (BMI), the presence of type 2 diabetes or other weight-related medical conditions, and an individual's overall health. Current clinical guidelines generally consider these medications for adults with obesity (BMI of 30 kg/m² or higher) or adults with a BMI of 27 kg/m² or higher who also have at least one weight-related medical condition.
A BMI threshold establishes eligibility for consideration, but it does not determine whether treatment is appropriate. The American Diabetes Association's Standards of Care in Diabetes (2026) notes that clinicians also consider medical history, current medications, treatment goals, and the potential benefits and risks of therapy before recommending GLP-1 medication.1 As a result, some people who meet the BMI criteria may still not be appropriate candidates for treatment.
What GLP-1 medications can and cannot do
Like any medical treatment, GLP-1 medications have defined strengths and equally important limitations. Seeing both side by side provides a complete picture of what these medications are designed to achieve and where they fit within long-term care.
| GLP-1 medications can | GLP-1 medications cannot |
|---|---|
| Support clinically meaningful weight loss and improved blood sugar control as part of comprehensive care.3 | Cure obesity or type 2 diabetes. |
| Provide cardiometabolic benefits, including improvements in blood pressure and insulin sensitivity.3 | Replace nutrition, physical activity, or behavioral care.1 |
| Work alongside lifestyle measures to support long-term disease management.1 | Guarantee a specific weight-loss outcome for any individual. |
| Remain effective when paired with adequate protein intake and strength training to help preserve muscle mass.16 | Prevent weight regain or reversal of metabolic benefits once treatment stops.8 |
Side effects and safety
Most side effects caused by GLP-1 receptor agonists are gastrointestinal, mild to moderate, and improve over time or with gradual dose increases. It is important to note that these medications are not appropriate for everyone because serious side effects, while uncommon, can occur and require prompt medical attention. The information below summarizes key safety considerations described in the FDA prescribing information for approved GLP-1 medications, particularly the Warnings and Precautions and Use in Specific Populations sections of the label.
| Common side effects | Serious risks and important cautions |
|---|---|
| Nausea | Acute pancreatitis (rare) |
| Vomiting | Gallbladder disease, including gallstones and cholecystitis |
| Diarrhea | Severe dehydration that may contribute to acute kidney injury |
| Constipation | Serious allergic reactions (hypersensitivity) |
| Abdominal pain, bloating, or discomfort | New or worsening depression, suicidal thoughts, or unusual changes in mood or behavior |
| Reduced appetite | Thyroid tumor risk; contraindicated with personal/family history of MTC or MEN2 |
| Not recommended during pregnancy |
Common side effects
Gastrointestinal side effects, including nausea, vomiting, diarrhea, constipation, abdominal discomfort, and reduced appetite, are the most common. They usually occur when treatment begins or after a dose increase and often improve over time.
Following the prescribed dose-escalation schedule, staying well hydrated, and maintaining adequate nutrition can improve tolerability. If symptoms are severe, persistent, or make it difficult to eat or drink, contact your prescribing clinician.
Serious risks and who should use caution
The FDA's prescribing information for approved GLP-1 medications identifies important safety risks, contraindications, and situations that require closer monitoring. Most people tolerate these medications well, but some side effects can be serious and require prompt medical attention.
According to the FDA's Warnings and Precautions section, these include pancreatitis, gallbladder disease, severe gastrointestinal reactions that may lead to dehydration and kidney injury, and serious allergic reactions.9 Some people, including those taking insulin or a sulfonylurea and those with diabetic retinopathy, may also require closer monitoring.
The FDA also advises against using GLP-1 medications during pregnancy and lists a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN2) as contraindications based on thyroid C-cell tumors observed in rodent studies, although no comparable risk has been established in humans.
Brand-name vs. compounded GLP-1 medications
Compounded GLP-1 medications are custom-prepared versions of drugs such as semaglutide and tirzepatide, made by a licensed compounding pharmacy for an individual patient. Compounding is intended to meet a specific clinical need when an FDA-approved medication cannot meet that patient's needs or is not commercially available. Compounded medications are not generic versions of FDA-approved GLP-1 drugs and should not be considered interchangeable with them.
Unlike FDA-approved GLP-1 medications, compounded products are not reviewed by the U.S. Food and Drug Administration (FDA) for safety, effectiveness, or manufacturing quality before they are dispensed. The FDA has also issued specific cautions about compounded GLP-1 products, which are summarized below.
| FDA warning | What you should know |
|---|---|
| Not FDA approved | Compounded GLP-1 medications are not FDA approved and are not reviewed by the FDA for safety, effectiveness, or quality before use. |
| Limited role | They may be appropriate only when a patient's medical needs cannot be met by an FDA-approved drug or when an approved product is not commercially available. |
| Dosing errors | FDA has received reports of dosing errors, including cases requiring hospitalization. |
| Salt forms | Some compounded semaglutide products use salt forms that differ from the active ingredient in FDA-approved medicines. |
| Adverse events | FDA has received reports of adverse events linked to compounded semaglutide and tirzepatide, although many cases may go unreported. |
Cost, insurance, and access
GLP-1 medications can be expensive, particularly for people paying out of pocket. The amount someone pays depends on the medication prescribed, insurance benefits, pharmacy pricing, and eligibility for manufacturer or public programs.
Insurance coverage is not uniform. Coverage is generally more established for FDA-approved diabetes indications than for obesity treatment, and benefits vary across commercial insurance, Medicare, and Medicaid. The Centers for Medicare & Medicaid Services (2025) describe recent policy changes that may expand coverage for some eligible Medicare beneficiaries, while noting that Medicaid coverage for obesity medications continues to vary by state.11
Even when a prescription is appropriate, access may be affected by insurance requirements, prior authorization, medication availability, and cost. Drug shortages also contributed to increased use of compounded GLP-1 medications in recent years. The FDA states that compounded GLP-1 products are not FDA-approved alternatives to approved medications and that routine compounding is now limited following the resolution of shortages for major GLP-1 drugs.12
Long-term use, maintenance, and stopping
Obesity and type 2 diabetes are chronic conditions that often require ongoing management, which is why GLP-1 medications may be prescribed as part of long-term care. In their systematic review, Shah et al. (2025) found that GLP-1 receptor agonists produced sustained weight loss and improvements in blood sugar control while treatment continued, supporting their role in long-term medical management for appropriately selected patients.13 The authors also note that evidence on long-term outcomes continues to evolve.
Maintaining treatment helps maintain its benefits. In the STEP 4 trial, Rubino et al. (2021) found that people who continued semaglutide maintained and extended their weight loss, while those who switched to placebo regained weight despite continuing lifestyle interventions.14 Similar findings were reported in the SURMOUNT-4 trial, where Aronne et al. (2024) found that participants who continued tirzepatide maintained substantially more of their weight loss than those who discontinued treatment.15
Stopping treatment can be followed by weight regain, but that does not mean the medication has failed. Instead, the available evidence reflects the chronic, relapsing nature of obesity. GLP-1 medications are generally considered part of ongoing disease management, not a short course of treatment.8 Whether continuing, adjusting, or stopping therapy is appropriate depends on an individual's health, response to treatment, and treatment goals, making regular follow-up with a qualified healthcare professional an important part of care.
Nutrition, protein, strength training, and follow-up care
Weight loss during GLP-1 treatment can include a reduction in lean body mass alongside body fat, making nutrition, particularly adequate protein intake, and strength training important considerations throughout care. Rossi et al. (2026) noted that muscle wasting during GLP-1 therapy raises particular concern for people already predisposed to sarcopenia, and that combining resistance exercise with adequate protein intake is among the most effective strategies for preserving muscle mass during treatment.16
Because muscle loss can progress gradually alongside fat loss, weight change alone is not a reliable way to track progress. Ongoing clinical follow-up gives a provider the opportunity to assess nutritional adequacy and functional strength over time, and to adjust the treatment plan if either is falling behind.
For practical guidance on nutrition, protein intake, strength training, and other lifestyle considerations during treatment, see our GLP-1 diet plan, where these topics are covered in greater depth.
Red flags in online GLP-1 information
The growing popularity of GLP-1 medications has also led to an increase in online sellers, telehealth services, and websites offering products that may not meet appropriate medical or regulatory standards. While many online providers operate legitimately, others may sell unapproved products or bypass important safeguards that help ensure treatment is safe and appropriate. The FDA summarizes these concerns in its guidance, FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss, which forms the basis for the recommendations below.10
| Be cautious if a provider or seller... | Why the FDA considers this a concern |
|---|---|
| Claims a compounded GLP-1 medication is "the same as" an FDA-approved drug. | Compounded products are not FDA approved and should not be presented as equivalent to approved medications. |
| Advertises prices that seem unusually low or too good to be true. | Large discounts can be a warning sign that a product may not come from a legitimate source. |
| Does not require an evaluation and prescription from a licensed healthcare professional. | GLP-1 medications are prescription drugs and should be prescribed only after an appropriate clinical assessment. |
| Does not provide access to a licensed clinician after treatment begins. | Patients should be able to ask questions and receive ongoing medical guidance during treatment. |
| Ships medication with damaged packaging, missing instructions, unusual labeling, or other signs that differ from legitimate pharmacy dispensing. | Packaging and labeling problems may indicate that the product should be evaluated more carefully before use. |
How to use the GLP-1 section of Revitalize Med
This guide is intended to provide a clear, evidence-based overview of GLP-1 medications. Some topics deserve more depth than a single article can provide. The resources in the Revitalize Med GLP-1 library explore those questions individually, with the same emphasis on clinical evidence, practical decision support, and clear explanations.
If you're looking for guidance on eating during treatment, meeting protein needs, or supporting muscle health while losing weight, start with our GLP-1 diet plan, which examines these topics in greater detail than is possible here.
As the evidence continues to evolve, this library will expand to include additional guides covering treatment decisions, safety, costs, and other aspects of GLP-1 therapy. Every article is grounded in current clinical guidance and peer-reviewed research, reviewed regularly, and updated when new evidence materially changes what patients should know.
Frequently asked questions
Are Ozempic and Wegovy the same?
No. Both contain semaglutide, but they are different FDA-approved medications with different approved uses, dosing, and prescribing information. They should not be used interchangeably.
Can GLP-1 medications cause muscle loss?
They can, but it isn't inevitable. Adequate protein, resistance training, and regular follow-up are important parts of GLP-1 treatment and may help preserve lean muscle during weight loss.
Do you regain weight after stopping a GLP-1?
Often, yes. Clinical trials show that many people regain weight after treatment stops, which is why long-term weight management usually extends beyond the medication itself.
Are compounded GLP-1 medications FDA-approved?
No. Compounded GLP-1 medications are not FDA-approved and are not reviewed by the FDA for safety, effectiveness, or quality before they are dispensed.
Can you take GLP-1 medications during pregnancy?
Generally, no. GLP-1 medications used for chronic weight management are not recommended during pregnancy and should be discussed with your healthcare professional if you are pregnant or planning to become pregnant.
Do you have to take GLP-1 medications forever?
Not necessarily. The right treatment duration depends on your medical condition, treatment goals, response to therapy, and your healthcare professional's recommendations.
References
- American Diabetes Association Professional Practice Committee. 8. Obesity and Weight Management for the Prevention and Treatment of Diabetes: Standards of Care in Diabetes—2026. Diabetes Care. 2026 Jan 1;49(Supplement_1):S166–S182. doi: 10.2337/dc26-S008.
- Moiz A, Filion KB, Tsoukas MA, Yu OH, Peters TM, Eisenberg MJ. Mechanisms of GLP-1 Receptor Agonist-Induced Weight Loss: A Review of Central and Peripheral Pathways in Appetite and Energy Regulation. Am J Med. 2025 Jun;138(6):934-940. PMID: 39892489.
- Popoviciu MS, Păduraru L, Yahya G, Metwally K, Cavalu S. Emerging Role of GLP-1 Agonists in Obesity: A Comprehensive Review of Randomised Controlled Trials. Int J Mol Sci. 2023 Jun 21;24(13):10449. PMID: 37445623.
- FDA Approved Labeling for Ozempic (NDA209637/S-035). Available at: accessdata.fda.gov.
- FDA Approved Labeling for Wegovy (NDA215256/S-024). Available at: accessdata.fda.gov.
- FDA Approved Labeling for Mounjaro (NDA 215866/S-039). Available at: accessdata.fda.gov.
- FDA Approved Labeling for Zepbound (NDA217806/S-042). Available at: accessdata.fda.gov.
- Quimbayo-Cifuentes AF. Weight Regain After GLP-1-Based Therapy Discontinuation: Failure, Physiology, or Follow-Up Gap. Cureus. 2026 Feb 25;18(2):e104259. PMID: 41909366.
- FDA Approved Labeling for Ozempic (NDA209637/S-025). Available at: accessdata.fda.gov.
- FDA Statement on Concerns with Unapproved and Compounded GLP-1 Drugs. Available at: fda.gov.
- CMS Press Release on the Launch of the BALANCE Model and GLP-1 Bridge. Available at: cms.gov.
- FDA Statement Clarifying Compounding Policies as GLP-1 Supply Stabilizes. Available at: fda.gov.
- Shah MY, Mohammad A, Bashir Ahmed Samejo R, et al. Weight Loss That Lasts: Reviewing the Long-Term Impact of GLP-1 Receptor Agonists. Cureus. 2025 Jul 19;17(7):e88334. PMID: 40837892.
- Rubino D, Abrahamsson N, Davies M, et al. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial. JAMA. 2021 Apr 13;325(14):1414-1425. PMID: 33755728.
- Aronne LJ, Sattar N, Horn DB, et al. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. JAMA. 2024 Jan 2;331(1):38-48. PMID: 38078870.
- Rossi G, Bucciarelli L, Mananguite CL, Giovarelli M, Fiorina P. Muscle loss and GLP-1R agonists use. Acta Diabetol. 2026 Feb;63(2):333-342. PMID: 41201615.