If you're considering GLP-1 medications for weight loss, you've probably encountered two names more than any other: semaglutide (Wegovy®/Ozempic®) and tirzepatide (Zepbound®/Mounjaro®). Both are injectable medications administered once weekly that produce significant weight loss, but they work through different mechanisms, have different clinical profiles, and may be covered differently by your insurance. Here's how they compare.
| Semaglutide | Tirzepatide | |
|---|---|---|
| Brand Names | Wegovy® (weight loss), Ozempic® (diabetes) | Zepbound® (weight loss), Mounjaro® (diabetes) |
| Mechanism | GLP-1 receptor agonist (single target) | GLP-1 + GIP dual receptor agonist (two targets) |
| Dosing | Once weekly injection, up to 2.4 mg | Once weekly injection, up to 15 mg |
| Average Weight Loss | ~15-17% of body weight (68 weeks, STEP trials) | ~20-22.5% of body weight (72 weeks, SURMOUNT trials) |
| Head-to-Head (SURMOUNT-5) | ~14% weight loss over 72 weeks | ~20% weight loss over 72 weeks |
| Patients Reaching ≥10% Loss | ~70% in clinical trials | ~85% in clinical trials |
| Long-Term Data | 68-week primary data; ongoing studies | 3-year SURMOUNT-1 extension showing sustained 22.9% loss |
| Common Side Effects | Nausea, vomiting, diarrhea, constipation | Nausea, diarrhea, decreased appetite, vomiting |
| FDA Approved (Weight Loss) | Yes (Wegovy, since June 2021) | Yes (Zepbound, since November 2023) |
| Additional Benefits | Cardiovascular risk reduction (SELECT trial) | 94% diabetes risk reduction in prediabetic patients (3-year data) |
| Insurance Coverage | Varies by plan — generally broader coverage due to longer market presence | Varies by plan — expanding but still less widely covered than semaglutide |
How they work: Semaglutide activates GLP-1 receptors, which reduce appetite and slow gastric emptying. Tirzepatide activates both GLP-1 and GIP receptors, addressing appetite through two distinct metabolic pathways. This dual mechanism is believed to be the primary driver of tirzepatide's greater weight loss in clinical trials.
Effectiveness: The SURMOUNT-5 trial — the first direct head-to-head comparison — showed tirzepatide producing approximately 20% average weight loss versus about 14% for semaglutide over 72 weeks. However, both medications significantly outperform older weight loss treatments, and individual responses vary. Some patients respond better to semaglutide, while others see greater results with tirzepatide.
Side effects: Both medications share a similar gastrointestinal side effect profile. Nausea, diarrhea, and constipation are the most common complaints, typically mild and improving over time. In the SURMOUNT-5 trial, discontinuation rates due to adverse events were comparably low for both. Under medical supervision, your provider manages these effects through gradual dose escalation and nutritional adjustments.
Insurance and cost: Semaglutide has been on the market longer (Wegovy since 2021) and generally has broader insurance coverage. Tirzepatide (Zepbound since late 2023) is gaining coverage but may be more difficult to get approved by certain insurance plans. For patients without branded coverage, compounded versions of both medications may be available at lower cost. Our team helps navigate your specific insurance situation during your assessment.
Whether you take semaglutide or tirzepatide, the medication addresses appetite — it doesn't address nutrition, muscle preservation, body composition, or long-term maintenance. Patients who lose 15-20%+ of their body weight on either medication face real risks of muscle loss, bone density reduction, and nutritional deficiencies if they're not supported by structured nutritional counseling and clinical monitoring.
Our Medi-Weightloss program pairs whichever medication your provider prescribes with a complete clinical support structure — personalized nutrition plans focused on adequate protein intake, weekly body composition tracking, dosage management based on your real-time clinical data, and a three-phase transition from active weight loss through long-term maintenance. The medication gets the weight off. The program keeps it off and protects your health in the process.