Semaglutide vs Tirzepatide: What's the Difference?

Who reviewed this article, and what it is not

Medically reviewed by [reviewing provider name, credentials and Florida license number], Optimal Wellness. Last reviewed August 25, 2026. Both prescribing labels were revised repeatedly through 2026 ⁴⁵, so if you are reading this long after that date, check the current prescribing information before you act on anything here.

This page is general education, not medical advice, and it is not a substitute for evaluation by a licensed provider who knows your history. Reading it does not create a provider-patient relationship. Do not start, stop or change any prescription medication based on what you read here.

What is the difference between semaglutide and tirzepatide?

The difference is how many receptors each medication switches on. Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist, so it works through one gut-hormone pathway ⁴. Tirzepatide acts on two, the glucose-dependent insulinotropic polypeptide (GIP) receptor and the GLP-1 receptor ⁵.

Those hormones tell your brain you have eaten, and they slow how quickly food leaves your stomach. FDA describes tirzepatide as activating gut-hormone receptors to reduce appetite and food intake ⁶. Semaglutide does much the same through one pathway.

Tirzepatide is injected under the skin once a week, on the same day each week ⁵. Semaglutide comes both ways: a once-weekly injection, or a once-daily tablet that starts at 1.5 mg and is maintained at 25 mg, so how you take it depends on which form you are prescribed ⁴. Two receptors instead of one is a real difference in pharmacology. It is not a promise that you will lose more, because trial results are averages and the spread is wide.

Which is FDA approved for weight loss: Wegovy, Zepbound, Ozempic or Mounjaro?

Wegovy and Zepbound. Those are the brands FDA approved for chronic weight management: Wegovy is semaglutide, Zepbound is tirzepatide ⁷. Both are approved alongside a reduced-calorie diet and increased physical activity for adults with obesity, or adults with overweight plus at least one weight-related condition such as high blood pressure, high cholesterol, type 2 diabetes or obstructive sleep apnea. In the trials behind those approvals, that meant a BMI of 30 or higher, or a BMI of 27 to 29.9 with a comorbidity ⁴⁵. Neither medication is approved for cosmetic weight loss below those thresholds, and a provider has to confirm you meet them before prescribing.

Ozempic and Mounjaro contain the same molecules under different names and are not on the approved-for-weight-management list ⁷. Mounjaro is approved to improve blood sugar in adults with type 2 diabetes ⁶.

Beyond weight, the two are not interchangeable. Wegovy is also indicated to reduce the risk of major adverse cardiovascular events in adults with established cardiovascular disease and either obesity or overweight, and, under accelerated approval pending a confirmatory trial, for noncirrhotic MASH with moderate to advanced fibrosis. The injection is approved from age 12; the tablet is for adults ⁴.

Zepbound is for adults only, and is also approved for moderate to severe obstructive sleep apnea in adults with obesity ⁵. So the medication that produced more weight loss head-to-head is not the one carrying the cardiovascular indication, which is worth knowing if you have heart disease.

How much weight do people lose on semaglutide vs tirzepatide?

In their pivotal trials, semaglutide averaged about 15% and tirzepatide about 21% at the highest dose. In STEP 1, adults taking semaglutide 2.4 mg lost a mean 14.9% of body weight at 68 weeks, versus 2.4% on placebo ². In SURMOUNT-1, mean weight change at 72 weeks was 15.0% on 5 mg tirzepatide, 19.5% on 10 mg and 20.9% on 15 mg ³.

Those are separate trials, so you cannot subtract one number from the other. The fair comparison came later. SURMOUNT-5, the only head-to-head trial of the weight-management doses in adults with obesity and without type 2 diabetes, assigned 751 people to the maximum tolerated dose of either medication for 72 weeks: average weight change was 20.2% with tirzepatide and 13.7% with semaglutide, with waist circumference down 18.4 cm versus 13.0 cm ¹.

Two caveats belong with that. It was open-label, so everyone knew what they were taking, and it was not designed to test whether the two are equally tolerable. The semaglutide dose was also capped at 2.4 mg. The higher-dose 7.2 mg option now on the Wegovy label did not exist then, and it is not a routine next step: the label reserves it for adults who have tolerated 2.4 mg for at least four weeks and for whom more weight reduction is clinically indicated ⁴.

How do semaglutide and tirzepatide compare side by side?

Here is the whole comparison in one place.

Our medical weight loss program is $250 a month for semaglutide and $400 a month for tirzepatide, and we accept CareCredit. Those prices sit below the cash price of branded Wegovy and Zepbound, so we do not leave you guessing: we name the exact product and strength you are prescribed — [insert exactly what is dispensed: FDA-approved Wegovy or Zepbound, or a compounded preparation and the pharmacy that makes it] — on your treatment plan and your receipt before you pay anything. If what you are prescribed is compounded, it is not Wegovy or Zepbound. Compounded drugs are not FDA approved, which means FDA does not review them for safety, effectiveness or quality before they are marketed ⁸. Your monthly price covers [state exactly what is and is not included: medication, supplies, visits, labs, refills].

What are the side effects, and is one easier on your stomach?

Most side effects are digestive, and common enough to plan for. The Wegovy label reports nausea, a single symptom, in 44% of adults taking 2.4 mg, versus 16% on placebo ⁴. The Zepbound label reports any gastrointestinal adverse reaction — a combined category that counts nausea, diarrhea, vomiting and constipation together — in 56% of patients at each maintenance dose, versus 30% on placebo ⁵. A combined category will always run higher than any single symptom inside it, so those two numbers are not measuring the same thing.

They also come from different trials, and both labels say so. In the head-to-head trial, gastrointestinal events were the most common adverse events in both groups, and most were mild to moderate ¹.

Stopping because of side effects is uncommon. About 6.8% discontinued Wegovy 2.4 mg due to adverse reactions, versus 3.2% on placebo, most often for nausea, vomiting or diarrhea ⁴. For Zepbound it was 4.8% to 6.7% depending on dose, versus 3.4% on placebo, and the label notes that most patients who stopped for adverse reactions did so in the first few months and because of gastrointestinal reactions ⁵. Both labels also carry these warnings.

• Acute pancreatitis: stop the medication and call your provider if you have persistent, severe abdominal pain ⁴⁵.
• Gallbladder disease, and acute kidney injury from dehydration after heavy vomiting or diarrhea ⁴⁵.
• Low blood sugar if you also take insulin, and serious allergic reactions including anaphylaxis and angioedema ⁴⁵.
• Delayed stomach emptying, which changes how oral medications are absorbed, and aspiration risk under anesthesia, so mention any planned procedure ⁴⁵.
• Diabetic retinopathy complications in people with type 2 diabetes. In a two-year trial of semaglutide in adults with type 2 diabetes and high cardiovascular risk, these occurred in 3% on semaglutide versus 1.8% on placebo, and in 8.2% versus 5.2% among people who already had retinopathy; the label says anyone with a history of diabetic retinopathy should be monitored ⁴. Tirzepatide's label carries the same warning ⁵.
• A rise in resting heart rate. The Wegovy label reports mean increases of 1 to 4 beats per minute and tells prescribers to check heart rate at regular intervals ⁴; the Zepbound label reports a mean increase of 1 to 3 beats per minute ⁵.
• Mood changes. Both labels carried a warning about suicidal behavior and ideation until it was removed in February 2026 ⁴⁵. That removal is not a reason to stay quiet: tell your provider about any history of depression or suicidal thoughts before you start, and report new or worsening mood changes while you are on treatment.

Who should not take semaglutide or tirzepatide?

Anyone with a personal or family history of medullary thyroid carcinoma, or with Multiple Endocrine Neoplasia syndrome type 2, should not take either one. Both carry a boxed warning: in rodents these medications caused thyroid C-cell tumors, and whether that applies to humans has not been determined ⁴⁵. Both labels list a second contraindication that is easy to miss — a known serious hypersensitivity reaction to that medication or to any of its ingredients rules out starting it at all ⁴⁵.

Neither belongs in pregnancy. Cleveland Clinic puts it plainly: never take weight loss drugs if you are pregnant, trying to get pregnant or breastfeeding ⁷. The Wegovy label advises stopping at least two months before a planned pregnancy, because semaglutide has a long half-life ⁴. If you take tirzepatide and use oral birth control, the label advises a non-oral or added barrier method for four weeks after you start and after each dose increase ⁵.

Neither is recommended in severe gastroparesis, and neither should be combined with another GLP-1 medication ⁴⁵. FDA noted at approval that Zepbound had not been studied in people with a history of pancreatitis or severe gastrointestinal disease ⁶. Whether either is right for you is a conversation with a licensed provider, not a decision to make from a web page.

Do you gain the weight back if you stop?

You give back much of it, though not all, and the trials are direct about that. In SURMOUNT-4, participants took tirzepatide for 36 weeks and lost an average 20.9% of their body weight, then were randomly assigned to continue or switch to placebo. Over the next 52 weeks the placebo group gained back 14.0%, ending 9.9% below their original starting weight, while those who continued lost a further 5.5% and ended 25.3% below baseline ⁹.

Cleveland Clinic says the same plainly: there is a high chance you will gain weight back when you stop ⁷. That is not a failure of willpower. Obesity behaves like a chronic condition, and these medications treat it while you take them.

So decide up front whether this is something you can continue. Both are approved for use alongside a reduced-calorie diet and increased physical activity, not instead of them ⁴⁵. Budget, follow-up and habits that outlive the prescription belong in the plan.

What is retatrutide, and is it FDA approved?

Retatrutide is investigational and is not FDA approved for any condition. FDA states that it cannot be used in compounding under federal law, is not a component of any FDA-approved drug, and has not been found safe and effective for any condition ⁸. The agency has warned telehealth companies for marketing unapproved drugs such as retatrutide directly to consumers ⁸.

It is in late-stage trials and may be approved one day. Until then, no version of it has been reviewed by FDA for safety, effectiveness or quality. If you see it advertised, slow down and ask questions.

Compounded semaglutide and tirzepatide raise a narrower version of the same question. Compounded drugs are not FDA approved, so the agency does not review them for safety, effectiveness or quality before they are marketed ⁸. FDA also names one consumer red flag outright: a company claiming its compounded drug is the same as an FDA-approved drug ⁸.

How do you start semaglutide or tirzepatide in Tampa or Wesley Chapel?

Start with a consultation, because both are prescription medications and both have eligibility criteria a provider has to confirm. A provider reviews your history, your medications and your goals, then stays with you through the dose increases, when most side effects show up. You can book a consultation by phone or text at +1-813-501-8341.

We have both Florida locations. Wesley Chapel is at The Shops at Wiregrass, 28329 Paseo Drive Unit 170, open Monday to Thursday 10 to 8, Friday and Saturday 10 to 9, Sunday 11 to 6. Walk-ins are welcome for our other services; weight-management medication requires a scheduled consultation and a provider evaluation first. Tampa is at 5027 W Laurel St near Westshore, by appointment. CareCredit is accepted.

One honest note about the rest of our menu. If dose escalation leaves you nauseated, or eating and drinking less, the first step is oral fluids and a call to your provider, not an infusion. Vomiting or diarrhea that is heavy or persistent needs to be evaluated, because both labels warn about acute kidney injury from dehydration and about pancreatitis ⁴⁵. We do offer an IV hydration drip, and some patients choose one for comfort once a provider has ruled out anything that needs treating. What we will not tell you is that a drip speeds up weight loss, or that it makes these medications work better or easier to tolerate. We have not seen trial evidence for either claim, so we do not make them.