GLP-1 comparison
Semaglutide vs. tirzepatide for weight loss
Both are FDA-approved, once-weekly GLP-1 injections that lower appetite. The short answer: in clinical trials tirzepatide produced greater average weight loss, roughly 20% versus 15%, while semaglutide has the longer safety record. The right choice is the one that fits your health, tolerance and coverage, decided with a physician, not a chart.
Medically reviewed by Dr. Roger Eduardo, MD, FASMBS, Board-Certified General Surgeon. Last reviewed August 2026.
Book a consultation →At a glance
The two medications, side by side. Individual results vary, these are averages from published trials and real-world data.
| Attribute | Semaglutide | Tirzepatide |
|---|---|---|
| Brand names | Wegovy (weight), Ozempic (diabetes) | Zepbound (weight), Mounjaro (diabetes) |
| Mechanism | GLP-1 receptor agonist (one hormone) | GIP + GLP-1 receptor agonist (two hormones) |
| Avg. weight loss (trials) | ~15% over 68 weeks (STEP 1) | ~20% over 72 weeks (SURMOUNT-1) |
| Real-world 1-year (head-to-head) | ~8% on-treatment | ~15% on-treatment (Rodriguez 2024) |
| How it's taken | Weekly self-injection, prefilled pen | Weekly self-injection, prefilled pen |
| Main side effects | GI: nausea, diarrhea, constipation | GI: nausea, diarrhea, constipation |
| Track record | Longer, approved for weight 2021 | Newer, approved for weight 2023 |
| Not for | MTC/MEN2 history; pregnancy | MTC/MEN2 history; pregnancy |
Sources: STEP 1 (Wilding et al., NEJM 2021); SURMOUNT-1 (Jastreboff et al., NEJM 2022); real-world one-year on-treatment comparison (Rodriguez et al., JAMA Internal Medicine 2024). Trial and real-world figures are population averages; your results depend on dose, adherence and your overall plan. Individual results vary.
Choosing between them
Bigger average loss isn't the whole story
Tirzepatide's higher average weight loss is real, but it is an average across thousands of people. What matters for you is which medication you tolerate, which your plan covers, your medical history, and your goals. Some patients do beautifully on semaglutide, which has been in weight-management use longer. Others plateau on it and benefit from tirzepatide's dual mechanism. This is exactly the judgment a physician-supervised program exists to make.
What Dr. Eduardo weighs
- ◆Your weight-loss goal and timeline.
- ◆How your body tolerates GI side effects.
- ◆Which medication your insurance covers.
- ◆Your medical history and contraindications.
- ◆Whether surgery may be the better long-term fit.
Semaglutide
The full page on Wegovy and Ozempic, how it works, candidacy, results and side effects.
Learn more →Tirzepatide
The full page on Zepbound and Mounjaro, mechanism, candidacy, expected results and cost.
Learn more →The Complete Program
Medication is one part. See the physician-supervised program that surrounds it.
Explore the program →Comparison FAQ
Semaglutide vs. tirzepatide questions
Can't find your answer here? Call us at (470) 742-1832 or book a consultation, we'll answer every question before you commit to anything.
On average, tirzepatide produced greater weight loss in clinical trials: adults lost about 20% of body weight over 72 weeks on tirzepatide (SURMOUNT-1) versus about 15% over 68 weeks on semaglutide (STEP 1). A head-to-head real-world study found similar direction (about 15% vs. 8% at one year). But averages are not individuals, semaglutide has a longer track record, tolerance differs person to person, and coverage often decides. Dr. Eduardo helps you choose. Sources: STEP 1 (NEJM 2021), SURMOUNT-1 (NEJM 2022), Rodriguez et al. (JAMA Internal Medicine 2024).
Semaglutide acts on a single gut-hormone receptor (GLP-1). Tirzepatide acts on two (GIP and GLP-1), which is thought to explain its larger average weight loss. Both are once-weekly self-injections that reduce appetite and slow stomach emptying. Semaglutide is sold as Wegovy and Ozempic; tirzepatide as Zepbound and Mounjaro.
Both share the same main side effects, gastrointestinal ones like nausea, diarrhea, vomiting and constipation, usually mildest at the lowest dose and easing as your body adjusts. Both carry the same boxed warning about thyroid C-cell tumors seen in rodents and are avoided in people with a personal or family history of medullary thyroid cancer or MEN2. Slow titration and protein-forward meals help with tolerance for either medication.
Cost depends far more on your insurance than on the molecule. When a plan covers a branded GLP-1, either is usually a copay. Without coverage, both have manufacturer self-pay programs (NovoCare for Wegovy; Lilly Direct for Zepbound) whose pricing changes over time. Our team verifies your specific benefits and explains current self-pay options before you start.
Sometimes, yes. If weight loss stalls, side effects are hard to tolerate, or coverage changes, Dr. Eduardo may discuss switching, always with a fresh evaluation and a careful re-titration rather than a like-for-like swap. Switching is a medical decision made with your physician, not something to do on your own.
No. Omnia Health prescribes only FDA-approved, branded medications: semaglutide (Wegovy, Ozempic) and tirzepatide (Zepbound, Mounjaro). We do not offer compounded versions, which are not FDA-evaluated for safety, quality or effectiveness.
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