Comparing Ozempic Vs Wegovy Vs Mounjaro
Ozempic (semaglutide), Wegovy (semaglutide), and Mounjaro (tirzepatide) are glucagon-like peptide 1 (GLP-1) agonists that are all known to cause weight loss and, therefore, are commonly used to treat obesity.
Although all three drugs are used for weight loss, their indications, side effects, and clinical trial results vary. Understanding the similarities and differences among these medications can help you work with your doctor to develop a weight-management treatment plan.
Table of Contents
Ozempic and Wegovy are brand names for semaglutide. They are both manufactured by Novo Nordisk. Ozempic is used to treat type 2 diabetes and prevent cardiovascular disease. Wegovy is used for chronic weight management in adults and adolescents aged 12 and older. Both medications are injectables and are intended to be used as part of a comprehensive plan that includes a nutritious diet and exercise.
Mounjaro is a glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonist manufactured by Eli Lilly. It is also an injectable and is approved to treat type 2 diabetes. Like Ozempic and Wegovy, people taking Mounjaro experience significant weight loss.
Mounjaro can be prescribed off-label to treat obesity, and Eli Lilly has received fast-track approval from the FDA. After submitting clinical trial results that support its weight loss potential, safety, and efficacy, the FDA is expected to approve a second indication for Mounjaro as a weight-loss medication.
Medication indications are based on the final outcomes of clinical trials. For example, to receive an indication for obesity treatment, a manufacturer must demonstrate that their drug safely and effectively treats obesity. Off-label use is when a clinician makes a medical judgment that a medication is an appropriate choice to treat a patient for a medical condition.
Wegovy is indicated for weight management, so eligibility criteria focus on body mass index, or BMI. People with a BMI of 30 or greater are eligible to take Wegovy. People with a BMI of 27 or higher and a weight-related medical condition such as high blood pressure, high cholesterol, or type 2 diabetes may also qualify. Adolescents must have a BMI at or above the 95th percentile for their age and weight.
Ozempic is prescribed to treat type-2 diabetes and off-label to treat obesity. The eligibility guidelines used to treat obesity are the same as for Wegovy.
Mechanism of Action
All three medications, Ozempic, Wegovy, and Mounjaro, are GLP-1 receptor agonists. GLP-1 agonists mimic the action of GLP-1 in the body. They boost insulin production in the pancreas and, therefore, help control blood sugar levels. They also reduce glucose production in the liver by lowering glucagon release.
GLP-1 agonists slow stomach emptying and reduce intestinal motility, which helps you feel full longer. Slowing stomach emptying helps stabilize blood glucose.
GLP-1 agonists also act in the brain. The gut releases GLP-1 after you consume food. It tells the brain you are full. Specialized neurons in the brain regulate food intake and energy expenditure. Other neurons that control reward, emotion, memory, attention, and cognition modulate weight-control neuronal activity. GLP-1 agonists reduce hunger and are thought to reduce food cravings.
Mounjaro is also a GIP agonist. It boosts insulin production and sensitivity. It slows stomach emptying by reducing stomach acid production.
Ozempic, Mounjaro, and Wegovy are all injectables that use a gradually increasing dose to minimize side effects.
Wegovy comes in pre-filled, single-dose pens that deliver doses of 0.25, 0.5, 1.0, 1.7, or 2.4 mg. The dose is slowly increased after four weeks on each dose until a 2.4 mg weekly dose is reached.
Ozempic comes in a 2 mg/1.5 ml and 2 mg/3 ml pen that is used to deliver doses of 0.25 mg or 0.5mg. A 4 mg/3 ml pen delivers 1 mg of Ozempic per dose, and an 8 mg/3 ml pen delivers 2 mg per dose. The dose of Ozempic is slowly increased to a maximum of 2mg weekly. The starting dose of 0.25 mg is ineffective for blood glucose control, per the manufacturer.
Mounjaro is available in multiple doses, from 2.5 mg to 15 mg. The starting dose is 2.5 mg injected under the skin once weekly. Every four weeks, the dose can be increased in 2.5 mg increments. The maximum dose is 15 mg, injected subcutaneously once a week.
The GLP-1 medications cause similar gastrointestinal side effects. Side effects typically increase when the drug is first started and when the dosage is increased.
Side effects associated with Wegovy include:
- Nausea (44%)
- Diarrhea (30%)
- Vomiting (24%)
- Constipation (24%)
- Stomach pain (20%)
- Headache (14%)
- Fatigue (11%)
- Heartburn (9%)
- Dizziness (8%)
- Stomach bloating (7%)
- Burping/flatulence (7%)
- Low blood sugar in people with type 2 diabetes (6%)
- Gas (6%)
- Gastroenteritis (6%)
- Acid reflux (5%)
- Stomach irritation (4%)
- Viral gastroenteritis (4%)
- Hair loss (3%)
Rare but more serious side effects include inflammation of the pancreas, gallbladder disease, diabetic retinopathy complications, and kidney disease. In animal studies, semaglutide increased the risk of thyroid cancer. If you have a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2, you should not take semaglutide.
Ozempic has similar side effects to Wegovy since it is also semaglutide, but at a lower severity since it is prescribed at a lower dose. The most commonly reported side effects are nausea, vomiting, diarrhea, abdominal pain, and constipation.
Mounjaro side effects include:
- Decreased appetite
- Stomach pain
Mounjaro can also cause the same serious side effects as Wegovy and Ozempic, including the risk of thyroid C-cell tumor, pancreatitis, low blood sugar, allergic reactions, acute kidney injury, severe gastrointestinal disease, diabetic retinopathy complications, and acute gallbladder disease.
Clinical Trial Results
The FDA-approved Wegovy to treat obesity based on the results of the Semaglutide Treatment Effect in People with Obesity (STEP) clinical trials. The average weight loss was almost 15% for adults and 16% for adolescents.
Ozempic clinical trials (SUSTAIN) included a series of eight trials focused on type 2 diabetes management and cardiovascular outcomes. Clinical trial participants taking Ozempic lowered their hemoglobin A1C (HgA1C) by over 1%, indicating that they achieved significantly better glucose control, as HgA1C is a measurement of average blood glucose over three months. The secondary clinical trial endpoint was weight loss. When patients with type 2 diabetes took Ozempic, they averaged a 6% to 7% weight loss.
In phase 3 clinical trials, participants with type 2 diabetes treated with Mounjaro lost an average of 12 to 25 pounds over 52 weeks. They had a reduction in HgA1C of between 1.8% and 2.4%.
In the Phase 3 SURMOUNT 1 study, at the end of 72 weeks, the mean weight loss for participants taking Mounjaro was:
- 15% for the 5 mg dose
- 19.5% for the 10 mg dose
- 20.9% for the 15 mg dose
- 3.1% for placebo
If you meet the eligibility guidelines and are interested in taking a GLP-1 agonist to support your weight loss efforts, contact an Invigor Medical treatment specialist to learn more about these medications.
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- Alabduljabbar, K., et al. (2022). The impact of once-weekly semaglutide 2.4mg will have on clinical practice: A focus on the STEP trials. Nutrients.
- FDA Center for Drug Evaluation & Research. (2020, August 20). Ozempic Drug Trial Snapshot. U.S. Food and Drug Administration. https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trial-snapshot-ozempic
- Frías JP, Davies MJ, Rosenstock J, et al; SURPASS-2 Investigators. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021 Aug 5;385(6):503-515. doi: 10.1056/NEJMoa2107519. Epub 2021 Jun 25. PMID: 34170647. Accessed Oct. 25, 2022.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al; SURMOUNT-1 Investigators. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022 Jul 21;387(3):205-216. doi: 10.1056/NEJMoa2206038. Epub 2022 Jun 4. PMID: 35658024.
- Kushner RF, Calanna S, Davies M, et al. Semaglutide 2.4 mg for the Treatment of Obesity: Key Elements of the STEP Trials 1 to 5. Obesity (Silver Spring). 2020 Jun;28(6):1050-1061. doi: 10.1002/oby.22794. PMID: 32441473; PMCID: PMC7318657.
- Eli Lily (2022). Mounjaro [package insert].
- Novo Nordisk. (2022). Ozempic [package insert].
- Novo Nordisk. (2022). Wegovy [package insert].
- Wharton, S., et al. (2022). Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity, and the relationship between gastrointestinal adverse events and weight loss. Diabetes, Obesity and Metabolism. 2022 Jan;24(1):94-105. doi: 10.1111/dom.14551.
- Wilding, J. P. H., et al. (2021). Once-weekly semaglutide in adults with overweight or obesity. The New England Journal of Medicine.