Mounjaro and Wegovy are brand names for prescription drugs used in combination with diet and other lifestyle changes to improve glycemic control in adults with type 2 diabetes mellitus.
Mounjaro and Wegovy are both classed as glucagon-like peptide-1 receptor agonists. Glucagon-like peptide-1 is a hormone produced by the intestines in response to food intake. It works in three main ways: controlling appetite, controlling blood sugar, and controlling intestinal movement. GLP-1 receptor agonists like Mounjaro and Wegovy work by mimicking the natural GLP-1 hormone our bodies produce.
Here we will explain how they work, their similarities and differences, their side effects, and more. This should provide you with the basics to better understand your options.
What is Mounjaro?
Mounjaro is an FDA (U.S. Food and Drug Administration) approved medication manufactured by Eli Lilly and Co. Mounjaro mimics 2 types of incretin hormones produced by the human body. It is classed as a GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist. GIP decreases food intake and increases energy expenditure which causes weight loss. When taken with a GLP-1 receptor agonist, it may result in greater positive effects on blood glucose and body weight.
Mounjaro is used to treat adults with type 2 diabetes mellitus. It is not for use in people with type 1 diabetes, pancreatitis, or to treat children under 18 years of age.
FDA approval for Lilly’s Mounjaro was based on the SURPASS study, which compared Mounjaro with Ozempic, insulin glargine, semaglutide 1 mg, and insulin degludec. Participants who took Mounjaro experienced an average reduction in hemoglobin A1c, and HbA1c (an indicator of blood sugar level). Participants who took a placebo saw an average increase in A1C levels.
Mounjaro is available in injection form, in the following doses: 2.5 mg/0.5 mL, 5 mg/0.5 mL, 7.5 mg/0.5 mL, 10 mg/0.5 mL, 12.5 mg/0.5 mL, or 15 mg/0.5 mL single-dose pens.
Mounjaro is injected subcutaneously in the abdomen, thigh, or upper arm once weekly, with or without food. If you miss a dose, take the missed dose as soon as possible within 96 hours after the missed dose. If more than 4 days have passed, skip the missed dose and take your next dose on the regularly scheduled day.
Use Mounjaro alongside dietary changes and exercise to improve glycemic control and always speak with a healthcare professional about any changes to your dose so they can monitor and evaluate your condition.
What is Wegovy?
Wegovy is an FDA (U.S. Food and Drug Administration) approved weight loss drug manufactured by Novo Nordisk. It is a higher-dose, 2.4 mg version of the diabetes drug Ozempic (semaglutide). Semaglutide is also manufactured in tablet form under the name Rybelsus.
Wegovy is a glucagon-like peptide-1 (GLP-1) receptor agonist indicated alongside a reduced-calorie diet and increased physical activity for chronic weight management in adult patients with a body mass index (BMI):
Wegovy is available in prefilled injection form, in the following doses: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, or 2.4 mg.
Wegovy is also a once-weekly injection, given on the same day each week, at any time of day, with or without meals. Inject Wegovy subcutaneously in the abdomen, thigh, or upper arm.
Start at 0.25 mg once weekly for 4 weeks. Increasing the dose 4 weekly until a dose of 2.4 mg is reached. The maintenance dose of Wegovy is 2.4 mg once weekly.
See the full prescribing information for the complete boxed warning for Wegovy. You are recommended to read the medication guide and advised to always speak with your healthcare provider about any changes to your dose so they can monitor and evaluate your condition.
Common side effects of Mounjaro and Wegovy
The most common side effects of Mounjaro in clinical trials include:
- Nausea, vomiting
- Gastrointestinal – diarrhea, decreased appetite, constipation, indigestion, abdominal pain
More serious side effects of Mounjaro include:
- Possible thyroid tumors, including thyroid cancer – do not use Mounjaro if you or any of your family have ever had a type of thyroid cancer called medullary thyroid carcinoma (MTC), or if you have an endocrine system condition called Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- Inflammation of your pancreas (pancreatitis) – symptoms include severe pain in your stomach area that will not go away, with or without vomiting
- Low blood sugar (hypoglycemia) – Your risk for low blood sugar may be increased if you use Mounjaro with another diabetes medication such as a sulfonylurea or insulin
- Serious allergic reactions
- Kidney problems
- Severe stomach problems
- Changes in vision
- Gallbladder problems
The most common side effects of Wegovy in clinical trials include:
- Nausea, vomiting
- Diarrhea, constipation, abdominal pain
- Headache, dizziness
- Dyspepsia, abdominal distension, eructation
- Hypoglycemia (low blood sugar) in patients with type 2 diabetes
- Flatulence, gastroenteritis, and gastroesophageal reflux disease (heartburn)
More serious side effects of Wegovy include
- Thyroid C-cell tumors
- Acute pancreatitis
- Acute gallbladder disease
- Acute kidney injury – monitor renal function when initiating or escalating doses if severe adverse gastrointestinal reactions occur
- Diabetic retinopathy complications in patients with Type 2 Diabetes
- Heart rate increase
- Suicidal behavior and ideation
These aren’t all the side effects Mounjaro or Wegovy can cause. You can find more details in the patient leaflet that comes with your medication. If you have any concerns about side effects, talk to your physician or pharmacist.
Mounjaro and Wegovy drug interactions
Mounjaro can interact with other medications. These include:
- Insulin secretagogue – sulfonylurea or Insulin
- Oral medications
- Orally administered hormonal contraceptives
Wegovy can interact with other medications. These include:
- Concomitantly administered oral medications – may affect absorption
Mounjaro and Wegovy can interact with other medications. This can change how Mounjaro and Wegovy and other medications work and can make side effects more likely. Tell your prescribing physician about all your drugs, including vitamins and dietary supplements.
Mounjaro and Wegovy contraindications
You should not use Mounjaro if you:
- Are allergic to the active ingredient tirzepatide
- Are allergic to any of the other ingredients in Mounjaro
Talk to your doctor before using Mounjaro if you:
- Are taking any of the medications that could interact with Mounjaro
- Have or have had problems with your pancreas or kidneys
- Have severe problems with your stomach
- Have a history of diabetic retinopathy
- Are pregnant or plan to become pregnant – If you take oral birth control pills by mouth, you may be recommended another type of birth control for 4 weeks after you start Mounjaro and for 4 weeks after each increase in your dose
- Are breastfeeding or planning to breastfeed. It is not known if Mounjaro passes into your breast milk
You should not use Wegovy if you:
- Are allergic to the active ingredient semaglutide
- Are allergic to any of the other ingredients in Wegovy
- Have a family history of medullary thyroid carcinoma
- Have multiple endocrine neoplasia syndrome type 2
- Are pregnant or are planning to become pregnant
Talk to your doctor before using Wegovy if you:
- Are taking any of the medications that could interact with Wegovy
- Are breastfeeding or are planning to breastfeed – it is unknown if this medication passes into breast milk
Other drugs for diabetes
If you have any concerns about Mounjaro or Wegovy side effects, talk to your physician, or pharmacist for medical advice. Also inform your healthcare provider about any medical conditions, supplements, and over-the-counter meds you are taking. You are also encouraged to report side effects to the FDA: visit http://www.fda.gov/medwatch or call 1-800-FDA-1088.