GLP-1 Medications: All the Names Explained
Ozempic, Wegovy, Mounjaro, Zepbound, Rybelsus — what's the difference? Your complete guide to GLP-1 and GIP/GLP-1 receptor agonists.
What Is a GLP-1 Receptor Agonist?
GLP-1 stands for glucagon-like peptide-1, a hormone your gut naturally releases after eating. It signals the pancreas to release insulin, slows stomach emptying (so you feel full longer), and signals the brain to reduce appetite. GLP-1 receptor agonists are medications that mimic this hormone — and they've transformed how we treat both type 2 diabetes and obesity.
These medications do not cause hypoglycemia (low blood sugar) on their own because they only stimulate insulin release when blood sugar is actually elevated — a significant safety advantage over older diabetes drugs.
Semaglutide: Ozempic, Wegovy & Rybelsus
Semaglutide is currently the most widely prescribed GLP-1 agent in the United States. It comes in three formulations:
Ozempic (injectable semaglutide — FDA approved for type 2 diabetes)
Ozempic is a once-weekly subcutaneous injection approved for type 2 diabetes management. It lowers A1c significantly and also reduces the risk of major cardiovascular events (heart attack, stroke) in people with established heart disease. While patients often lose weight on Ozempic, it is not FDA approved for weight loss — Wegovy is.
Wegovy (injectable semaglutide — FDA approved for chronic weight management)
Wegovy contains the same semaglutide molecule as Ozempic but at a higher maximum dose (2.4 mg vs 1.0 mg weekly). It's approved for adults with obesity (BMI ≥30) or overweight (BMI ≥27) with a weight-related condition. Clinical trials showed average weight loss of 15% of body weight — a landmark result that transformed obesity medicine.
Rybelsus (oral semaglutide — FDA approved for type 2 diabetes)
Rybelsus is the first oral GLP-1 medication — the same semaglutide molecule in pill form. It must be taken on an empty stomach with a small amount of water and no other food or drink for 30 minutes. It's approved for type 2 diabetes, not weight loss, though weight reduction is a common benefit.
Tirzepatide: Mounjaro & Zepbound
Tirzepatide is a newer and more powerful agent that activates two receptors — both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). This dual action produces more potent effects on blood sugar and weight than GLP-1 alone.
Mounjaro (tirzepatide — FDA approved for type 2 diabetes)
Mounjaro is a once-weekly injection for type 2 diabetes that produces some of the most impressive A1c reductions seen in clinical trials. Like Ozempic, weight loss is common but the diabetes indication is the approved use.
Zepbound (tirzepatide — FDA approved for chronic weight management)
Zepbound is Mounjaro rebranded for weight loss. Clinical trials showed average weight loss of 20–22% of body weight — the largest ever seen in a weight loss medication trial. It's approved for obesity or overweight with a weight-related health condition.
Older GLP-1 Agents
Several older GLP-1 medications are still in use, primarily for diabetes:
- Victoza (liraglutide): Once-daily injection for type 2 diabetes. Also has cardiovascular benefit data.
- Saxenda (liraglutide): The same molecule as Victoza at a higher dose, approved for weight loss.
- Trulicity (dulaglutide): Once-weekly injection for type 2 diabetes with heart and kidney protection data.
- Byetta / Bydureon (exenatide): Earlier GLP-1 agents, less commonly prescribed now with newer options available.
Side-by-Side Comparison
| Brand Name | Generic | Type | FDA Approval | How Often |
|---|---|---|---|---|
| Ozempic | Semaglutide | GLP-1 | Type 2 Diabetes | Once weekly (injection) |
| Wegovy | Semaglutide | GLP-1 | Weight Loss | Once weekly (injection) |
| Rybelsus | Semaglutide | GLP-1 | Type 2 Diabetes | Once daily (pill) |
| Mounjaro | Tirzepatide | GIP + GLP-1 | Type 2 Diabetes | Once weekly (injection) |
| Zepbound | Tirzepatide | GIP + GLP-1 | Weight Loss | Once weekly (injection) |
| Victoza | Liraglutide | GLP-1 | Type 2 Diabetes | Once daily (injection) |
| Saxenda | Liraglutide | GLP-1 | Weight Loss | Once daily (injection) |
| Trulicity | Dulaglutide | GLP-1 | Type 2 Diabetes | Once weekly (injection) |
Which Medication Is Right for You?
Choosing among these medications depends on several factors that your endocrinologist will evaluate:
- Primary goal: Is the main concern blood sugar control, weight loss, or both?
- Insurance coverage: Coverage varies significantly between brands — your doctor can help navigate prior authorizations.
- Cardiovascular history: Some agents have specific data in patients with heart disease or kidney disease.
- Pill vs. injection preference: Rybelsus is the only oral option.
- Side effect profile: Nausea, vomiting, and constipation are common, especially early on. Dose titration and dietary adjustments can minimize these.
Our endocrinologists have extensive experience prescribing and managing all GLP-1 agents. We'll help you find the right medication, dose, and monitoring plan for your specific situation. Book an Appointment
In-Depth Guides by Brand
Search for your medication by name and go deeper — each guide covers how it works, dosing, clinical results, side effects, and FAQs:
Semaglutide · Type 2 Diabetes · Once weekly · ~5–7% weight loss
Semaglutide · Weight Management · 2.4 mg · ~15% weight loss
Tirzepatide · Type 2 Diabetes · Dual GIP+GLP-1 · ~15–21% weight loss
Tirzepatide · Weight Management · ~20–22% weight loss · Most powerful option
Frequently Asked Questions
What is the difference between Ozempic and Wegovy?
Both contain semaglutide, but at different doses. Ozempic (max 2 mg) is FDA-approved for Type 2 diabetes; Wegovy (max 2.4 mg) is approved for weight management. Wegovy produces about 15% average weight loss vs 5–7% for Ozempic. They also use different insurance pathways: Ozempic goes through diabetes coverage, Wegovy through obesity coverage.
What is the difference between Mounjaro and Zepbound?
They are the same drug — tirzepatide — made by Eli Lilly. Mounjaro is approved for Type 2 diabetes; Zepbound is approved for weight management. The clinical effect is identical; the distinction matters for insurance coverage. Your endocrinologist will prescribe the appropriate version for your diagnosis and coverage.
Is Zepbound or Wegovy better for weight loss?
In head-to-head trials, tirzepatide (Zepbound) produced approximately 47% more weight loss than semaglutide (Wegovy) at 72 weeks. Both are excellent medications, and the best choice depends on your individual health history, side effect tolerance, and insurance coverage. An endocrinologist can help you decide.
Do I need an endocrinologist to get these medications?
While some primary care and weight loss clinics prescribe GLP-1 medications, an endocrinologist is the specialist best equipped to evaluate your complete metabolic picture, manage interactions with diabetes medications (especially insulin), monitor for endocrine complications, and optimize dosing. This is especially important if you have Type 2 diabetes, thyroid disease, or complex medical history.
What are the common side effects of GLP-1 medications?
The most common side effects across all GLP-1 and GIP/GLP-1 medications are gastrointestinal: nausea, vomiting, diarrhea, and constipation. These are most prominent when starting the medication or increasing the dose, and typically improve over several weeks. Eating smaller meals, avoiding high-fat foods, and taking the injection at night can help. Serious but rare risks include pancreatitis and gallbladder disease.
How do I get a prescription for Ozempic, Wegovy, Mounjaro, or Zepbound in Houston?
Book an appointment at Endocrine & Diabetes Plus Clinic of Houston. Our board-certified endocrinologists will evaluate your medical history, review your glucose data, and determine which medication — if any — is appropriate for your situation. We handle the prescription, prior authorization, and ongoing management. Call 832-968-7003 or book online.