Weight Loss & Metabolic Health

    Tirzepatide vs. Semaglutide: How They Differ

    Published · Haute MD Editorial Team

    A hand holds a white injection pen with a clear dose window marked 0.25 mg, 0.5 and 1.5, against a wall with a plant shadow. Illustrative stock image; not a Haute MD doctor or patient, and not a specific brand.

    Tirzepatide and semaglutide are both once-weekly incretin medicines, but they work differently: tirzepatide (sold as Mounjaro and Zepbound) activates two hormone receptors, GIP and GLP-1, while semaglutide (Ozempic, Wegovy and Rybelsus) activates GLP-1 only. They also come in different forms and carry different FDA-approved uses. Tirzepatide is an injection only. Semaglutide comes as a weekly injection or a daily tablet. Mounjaro and Ozempic are approved for type 2 diabetes; Zepbound and Wegovy are approved for weight reduction, with Zepbound also approved for obstructive sleep apnea and Wegovy for cardiovascular risk reduction and a form of fatty liver disease. In the one head-to-head trial in FDA labeling (SURPASS-2, in adults with type 2 diabetes), tirzepatide lowered A1C and body weight more than semaglutide 1 mg over 40 weeks. Which, if either, fits you is a decision to make with a physician.

    At a glance

    TirzepatideSemaglutide
    How it worksGIP and GLP-1 receptor agonistGLP-1 receptor agonist
    BrandsMounjaro (diabetes), Zepbound (weight, sleep apnea)Ozempic injection and Ozempic tablets, Rybelsus (diabetes); Wegovy injection and Wegovy tablets (weight, heart risk)
    FormWeekly injectionWeekly injection or daily tablet
    Diabetes dosesMounjaro 2.5 mg start, up to 15 mg weekly (adults)Ozempic 0.25 mg start, up to 2 mg weekly; tablets daily
    Weight-management dosesZepbound 5, 10 or 15 mg weekly maintenanceWegovy 2.4 mg weekly (up to 7.2 mg in adults) or 25 mg tablet daily
    Boxed warningThyroid C-cell tumors in rodentsThyroid C-cell tumors in rodents
    Oral birth control noteYes: switch method or add a barrier method after starting and each dose increaseNot in the Wegovy label

    What each brand is FDA-approved for

    Tirzepatide

    • Mounjaro (injection): with diet and exercise, to improve blood sugar in adults and children 10 and older with type 2 diabetes; and to reduce the risk of major cardiovascular events (heart attack, stroke or cardiovascular death) in adults with type 2 diabetes at high risk for them.
    • Zepbound (injection): with a reduced-calorie diet and more physical activity, to reduce excess body weight and keep it off long term in adults with obesity, or with overweight plus at least one weight-related condition; and to treat moderate to severe obstructive sleep apnea in adults with obesity.

    Semaglutide

    • Ozempic (injection): to improve blood sugar in adults with type 2 diabetes; to reduce major cardiovascular events in adults with type 2 diabetes and established cardiovascular disease; and to reduce the risk of kidney function decline, kidney failure and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.
    • Ozempic tablets and Rybelsus (daily tablets): to improve blood sugar in adults with type 2 diabetes, and to reduce major cardiovascular events in adults with type 2 diabetes at high risk. The two tablets are not interchangeable milligram for milligram.
    • Wegovy (injection): to reduce major cardiovascular events in adults with established cardiovascular disease and obesity or overweight; to reduce excess weight and keep it off in adults and in children 12 and older with obesity, and in adults with overweight plus a weight-related condition; and, under accelerated approval, to treat noncirrhotic MASH with moderate to advanced liver fibrosis in adults.
    • Wegovy (tablets): to reduce major cardiovascular events in adults with established cardiovascular disease and obesity or overweight, and to reduce excess weight and keep it off in adults.

    The Zepbound and Wegovy labels say not to combine them with other tirzepatide- or semaglutide-containing products, as applicable, or with any other GLP-1 medicine.

    How they work

    Both drugs mimic incretins, gut hormones released after eating. Semaglutide acts on the GLP-1 receptor. Tirzepatide is a single molecule that acts on both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor; its labels describe it as "a GIP receptor and GLP-1 receptor agonist." Both are started at a low dose and raised in steps every four weeks (every 30 days for tablets) to reduce stomach side effects.

    Tablets come with rules. Oral semaglutide is taken once a day on an empty stomach in the morning with up to 4 ounces of plain water, swallowed whole, followed by at least 30 minutes before food, drink or other oral medicines.

    What the FDA labels report from trials

    Head to head, type 2 diabetes (SURPASS-2, Mounjaro label). In 1,879 adults with type 2 diabetes on metformin, after 40 weeks:

    Semaglutide 1 mgTirzepatide 5 mgTirzepatide 10 mgTirzepatide 15 mg
    A1C change (points)−1.9−2.0−2.2−2.3
    Body weight change (kg)−5.7−7.6−9.3−11.2

    All three tirzepatide doses beat semaglutide 1 mg on both measures. This trial used Ozempic's 1 mg dose, not the higher doses approved for weight management.

    Weight management (separate placebo-controlled trials). These results come from different trials with different patients and lengths, so they can't be compared directly:

    Label and trialWhoLengthAverage weight change, drug vs. placebo
    Zepbound, Study 1Adults with obesity or overweight, no diabetes72 weeks−15.0% (5 mg), −19.5% (10 mg), −20.9% (15 mg) vs. −3.1%
    Zepbound, Study 2Adults with type 2 diabetes72 weeks−12.8% (10 mg), −14.7% (15 mg) vs. −3.2%
    Wegovy 2.4 mg injection, Study 2Adults with obesity or overweight plus a condition68 weeks−14.9% vs. −2.4%
    Wegovy 2.4 mg injection, Study 3Adults with type 2 diabetes68 weeks−9.6% vs. −3.4%
    Wegovy 7.2 mg injection, Study 8Adults with obesity72 weeks−18.8% (7.2 mg), −15.5% (2.4 mg) vs. −3.9%
    Wegovy 25 mg tablet, Study 7Adults with obesity or overweight plus a condition64 weeks−13.6% vs. −2.4%

    Every trial paired the drug with diet and exercise counseling. Averages describe groups, not what any one person will lose.

    Safety: mostly shared, a few differences

    Shared. Every label carries a boxed warning: in rodents, the drug caused thyroid C-cell tumors, and it is unknown whether it does in people. Each is contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2. Warnings common to both include pancreatitis, gallbladder disease, low blood sugar when used with insulin or sulfonylureas, kidney injury from dehydration, severe stomach side effects (not recommended with severe gastroparesis), serious allergic reactions, worsening diabetic eye disease in people with a history of it, and a risk of inhaling stomach contents during anesthesia or deep sedation, so tell your surgical team you take one.

    Common side effects. Both labels list nausea, diarrhea, vomiting, constipation, abdominal pain, indigestion, burping, reflux, fatigue and hair loss among the most common. Zepbound's list also includes injection-site and allergic reactions; Wegovy's adds headache, dizziness, bloating and gas.

    Differences in the labels.

    • Birth control pills: the Mounjaro and Zepbound labels tell patients on oral hormonal contraceptives to switch to a non-oral method, or add a barrier method, for four weeks after starting and after each dose increase. Non-oral hormonal methods aren't affected.
    • Heart rate: Wegovy's label lists heart rate increase as a warning and advises monitoring. The Mounjaro and Zepbound labels report mean heart rate increases in their adverse-reactions sections.
    • Tablet dosing: only semaglutide has a pill, with the empty-stomach rules above.

    Questions to ask your doctor

    • Which FDA-approved use applies to me: diabetes, weight, sleep apnea, heart risk or liver disease?
    • Would a weekly injection or a daily tablet suit my routine?
    • How would my other medicines, including insulin, sulfonylureas or birth control pills, need to change?
    • Do I have a history of pancreatitis, gallbladder disease, thyroid cancer in the family, diabetic eye disease or severe gastroparesis?
    • What dose would we start at, how fast would we increase it, and how will we track progress and side effects?
    • Am I planning surgery or a procedure with sedation?

    Talk to a physician

    Browse Find a Doctor or Miami Physicians on Haute MD.

    Featured doctors: Dr. Ari Cohen, a board-certified internal medicine physician in Aventura, Florida, whose clinical focus includes diabetes management and obesity medicine; and Dr. Kern Brar, a board-certified internal medicine physician and founder of A Personal Physician, a concierge and executive medicine practice in Encinitas, Oceanside and La Jolla, California, whose programs include medically supervised weight loss and obesity medicine.

    Related

    Sources

    This guide is general information, not medical advice. Talk to a licensed physician about your own health and medicines.

    Frequently Asked Questions

    What is the difference between tirzepatide and semaglutide?

    Tirzepatide activates both GIP and GLP-1 receptors; semaglutide activates GLP-1 only. Tirzepatide comes only as a weekly injection (Mounjaro, Zepbound). Semaglutide comes as a weekly injection (Ozempic, Wegovy) or a daily tablet (Ozempic tablets, Rybelsus, Wegovy tablets).

    Is Mounjaro the same as Zepbound?

    Both contain tirzepatide, but they are separate products with different FDA-approved uses. Mounjaro is approved for type 2 diabetes and cardiovascular risk reduction in type 2 diabetes; Zepbound is approved for weight reduction 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 risk reduction. Wegovy is approved for weight reduction, cardiovascular risk reduction in adults with heart disease and obesity or overweight, and, for the injection, MASH with liver fibrosis.

    Has tirzepatide been compared directly with semaglutide?

    In FDA labeling, yes, in type 2 diabetes. In SURPASS-2, tirzepatide 5, 10 and 15 mg lowered A1C and body weight more than semaglutide 1 mg over 40 weeks.

    Is there a tirzepatide pill?

    No tirzepatide tablet is FDA-approved. Semaglutide is available as daily tablets: Ozempic tablets and Rybelsus for type 2 diabetes, and Wegovy tablets for weight reduction and cardiovascular risk reduction.

    Can you take tirzepatide and semaglutide together?

    They aren't meant to be combined. The Zepbound and Wegovy labels say coadministration with other tirzepatide or semaglutide products or with any other GLP-1 medicine is not recommended.

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