Semaglutide vs Tirzepatide: Ozempic & Wegovy vs Mounjaro & Zepbound

Quick Answer: Semaglutide is a GLP-1 receptor agonist sold as Ozempic (type 2 diabetes) and Wegovy (weight management, cardiovascular risk reduction, and MASH). Tirzepatide activates both GIP and GLP-1 receptors and is sold as Mounjaro (type 2 diabetes) and Zepbound (weight management and obstructive sleep apnea). In the head-to-head SURMOUNT-5 trial in adults with obesity without diabetes, mean weight change at 72 weeks was −20.2% with tirzepatide vs −13.7% with semaglutide. In SURPASS-2 in type 2 diabetes, tirzepatide lowered HbA1c more than semaglutide 1 mg. Both carry a boxed warning about thyroid C-cell tumors and share similar gastrointestinal side effects. These are prescription drugs; the right choice depends on your diagnosis, other conditions, coverage and tolerance.

Semaglutide vs Tirzepatide at a Glance

Feature	Semaglutide	Tirzepatide
Mechanism	GLP-1 receptor agonist	GIP and GLP-1 receptor agonist
Diabetes brand	Ozempic	Mounjaro
Weight brand	Wegovy (injection; tablets also listed)	Zepbound
Dosing	Once-weekly injection; Wegovy tablets once daily	Once-weekly injection
Starting dose (injection)	0.25 mg weekly for 4 weeks	2.5 mg weekly for 4 weeks
Maximum / maintenance	Ozempic up to 2 mg; Wegovy usual maintenance 2.4 mg	Up to 15 mg (Zepbound maintenance 5, 10 or 15 mg)
Other labeled uses	Ozempic: CV risk and kidney outcomes in T2D. Wegovy: CV risk in established CVD; MASH	Mounjaro: CV risk in high-risk T2D. Zepbound: moderate-to-severe OSA with obesity
Boxed warning	Risk of thyroid C-cell tumors	Risk of thyroid C-cell tumors

Indications and doses are from the current DailyMed prescribing information listed in Sources. Labels are updated often; your prescriber will follow the current label.

Same Idea, Different Molecules

Both drugs mimic gut hormones (incretins) that are released after eating. GLP-1 (glucagon-like peptide-1) increases insulin release when blood sugar is high, lowers glucagon, slows stomach emptying, and acts on appetite centers in the brain. Semaglutide activates the GLP-1 receptor only. Tirzepatide is a single molecule that activates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. That dual action is the main reason it is studied as a distinct drug rather than “a stronger Ozempic.”

Each molecule is marketed under two brand names with different FDA-approved uses. The brand on your prescription matters, because insurance coverage and dosing follow the labeled indication.

What Each Brand Is Approved For

Ozempic (semaglutide injection)

Per its label: to improve blood sugar control in adults with type 2 diabetes alongside diet and exercise; to reduce the risk of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease; and to reduce the risk of sustained kidney function decline, end-stage kidney disease and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.

Wegovy (semaglutide)

With a reduced-calorie diet and increased physical activity: to reduce major adverse cardiovascular events in adults with established cardiovascular disease and obesity or overweight; to reduce excess body weight and maintain weight reduction long term in adults and children 12 and older with obesity, and in adults with overweight plus at least one weight-related condition; and, under accelerated approval, to treat noncirrhotic MASH with moderate to advanced liver fibrosis in adults. The current DailyMed listing includes both Wegovy injection and Wegovy tablets.

Mounjaro (tirzepatide)

To improve blood sugar control in adults and children 10 and older with type 2 diabetes, and to reduce major adverse cardiovascular events in adults with type 2 diabetes at high risk for these events.

Zepbound (tirzepatide)

With a reduced-calorie diet and increased physical activity: to reduce excess body weight and maintain weight reduction long term in adults with obesity, or overweight with at least one weight-related condition; and to treat moderate to severe obstructive sleep apnea in adults with obesity.

What the Trials Found

Head-to-head for weight: SURMOUNT-5

In SURMOUNT-5 (Aronne et al., New England Journal of Medicine, 2025), 751 adults with obesity but without diabetes were randomized to the maximum tolerated dose of tirzepatide (10 or 15 mg) or semaglutide (1.7 or 2.4 mg) weekly. At week 72, mean weight change was −20.2% with tirzepatide and −13.7% with semaglutide; waist circumference fell 18.4 cm vs 13.0 cm. More tirzepatide participants reached weight reductions of at least 10%, 15%, 20% and 25%. The most common side effects in both groups were gastrointestinal, mostly mild to moderate and concentrated during dose escalation.

Head-to-head for diabetes: SURPASS-2

In SURPASS-2 (Frías et al., NEJM, 2021), adults with type 2 diabetes on metformin received tirzepatide 5, 10 or 15 mg or semaglutide 1 mg weekly. HbA1c fell by 2.01, 2.24 and 2.30 percentage points with the three tirzepatide doses versus 1.86 points with semaglutide; all tirzepatide doses were noninferior and superior. Weight reductions were also greater with tirzepatide (treatment differences of 1.9 to 5.5 kg). Note the semaglutide dose was 1 mg, lower than the 2 mg Ozempic maximum now on the label.

Placebo-controlled weight trials

In STEP 1 (Wilding et al., 2021), semaglutide 2.4 mg produced mean weight change of −14.9% at 68 weeks vs −2.4% with placebo. In SURMOUNT-1 (Jastreboff et al., 2022), tirzepatide produced −15.0%, −19.5% and −20.9% at 5, 10 and 15 mg vs −3.1% with placebo at 72 weeks. These were separate trials with different populations, so their numbers should not be compared directly; SURMOUNT-5 is the direct comparison.

Heart outcomes

In SELECT (Lincoff et al., 2023), 17,604 adults with established cardiovascular disease and overweight or obesity but no diabetes received semaglutide 2.4 mg or placebo. A major cardiovascular event occurred in 6.5% vs 8.0% (hazard ratio 0.80). This trial supports Wegovy’s cardiovascular indication. Mounjaro’s cardiovascular indication applies to adults with type 2 diabetes at high risk.

Dosing Schedules

Both start low and step up every 4 weeks to reduce nausea and other GI effects.

Ozempic: 0.25 mg weekly for 4 weeks, then 0.5 mg; may increase to 1 mg and then 2 mg weekly based on glucose control (maximum 2 mg).
Wegovy injection: starts at 0.25 mg weekly and is titrated every 4 weeks; the usual maintenance dose is 2.4 mg weekly, with indication-specific maintenance doses in the full label. Wegovy tablets are taken once daily on an empty stomach with a small amount of water.
Mounjaro and Zepbound: 2.5 mg weekly for 4 weeks, then increase in 2.5 mg steps at least 4 weeks apart. Zepbound maintenance for weight is 5, 10 or 15 mg; for sleep apnea, 10 or 15 mg. Maximum 15 mg.

Do not combine products: the Zepbound label says coadministration with other tirzepatide-containing products or any GLP-1 receptor agonist is not recommended.

Side Effects and Warnings

The labels for both drugs list similar risks:

Boxed warning: risk of thyroid C-cell tumors seen in rodents. Both are contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Gastrointestinal effects: nausea, diarrhea, vomiting, constipation and abdominal pain are the most common, especially when increasing the dose.
Pancreatitis, gallbladder disease, acute kidney injury (often from dehydration with GI side effects), and hypoglycemia when combined with insulin or sulfonylureas.
Pulmonary aspiration risk during anesthesia or deep sedation because of delayed stomach emptying; tell your surgical team you take one.
Diabetic retinopathy complications have been reported in people with diabetes, particularly with rapid glucose improvement.
Oral contraceptives: the tirzepatide labels advise switching to a non-oral method or adding a barrier method for 4 weeks after starting and after each dose increase, because delayed stomach emptying may reduce absorption.

Weight typically returns after stopping either drug unless lifestyle changes or ongoing treatment continue; the labels describe these as long-term therapies.

Compounded and Online Versions

FDA has warned about unapproved and compounded semaglutide and tirzepatide products, including reports of dosing errors and products sold online that may contain the wrong ingredient or amount. FDA-approved versions are Ozempic, Wegovy, Rybelsus (oral semaglutide for diabetes), Mounjaro and Zepbound. Get these medicines from a state-licensed pharmacy with a valid prescription.

How Prescribers Choose

Diagnosis: type 2 diabetes points to Ozempic or Mounjaro; weight management without diabetes points to Wegovy or Zepbound.
Other conditions: established cardiovascular disease (Wegovy’s CV indication), chronic kidney disease with diabetes (Ozempic), sleep apnea (Zepbound) or MASH (Wegovy) can tip the choice.
Magnitude of effect: head-to-head trials favored tirzepatide for weight and HbA1c reduction.
Tolerance, coverage and supply: insurance criteria differ by brand and indication; some plans cover diabetes brands but not weight brands. Neither has a generic version in the U.S. as of this update.

When to Talk to Your Doctor or Pharmacist

Seek care right away for severe stomach pain that won’t go away (with or without vomiting), which can signal pancreatitis; pain in the upper right abdomen, fever or yellowing skin (gallbladder problems); a lump or swelling in the neck, trouble swallowing or persistent hoarseness; signs of a serious allergic reaction; or signs of dehydration from ongoing vomiting or diarrhea. Tell your clinician before any surgery or procedure with sedation.

Frequently Asked Questions

Is Mounjaro the same as Zepbound?

Both contain tirzepatide. Mounjaro is approved for type 2 diabetes (and cardiovascular risk reduction in high-risk type 2 diabetes); Zepbound is approved for weight management and obstructive sleep apnea with obesity.

Is Ozempic the same as Wegovy?

Both contain semaglutide. Ozempic is approved for type 2 diabetes and related heart and kidney outcomes; Wegovy is approved for weight management, cardiovascular risk reduction in people with established heart disease and overweight or obesity, and MASH.

Which causes more weight loss, semaglutide or tirzepatide?

In the head-to-head SURMOUNT-5 trial in adults with obesity without diabetes, mean weight change at 72 weeks was −20.2% with tirzepatide vs −13.7% with semaglutide.

Do they have the same side effects?

Largely similar: mostly gastrointestinal effects such as nausea, diarrhea, vomiting and constipation, plus shared warnings for pancreatitis, gallbladder disease and a boxed warning about thyroid C-cell tumors.

Can I switch from Ozempic to Mounjaro?

Prescribers do switch patients, but the dose is re-titrated. Do not use both together; the tirzepatide labels advise against combining with any GLP-1 receptor agonist.

Are compounded versions the same?

No. Compounded products are not FDA-approved, and FDA has warned about dosing errors and products with incorrect ingredients. Use FDA-approved products from licensed pharmacies.

Sources

Medical disclaimer: This article is for educational purposes and does not replace medical advice. Consult a licensed healthcare provider before starting any supplement, medication, or treatment — particularly if you are pregnant, breastfeeding, taking other medications, or have a diagnosed medical condition.