Mounjaro® (tirzepatide) for weight loss
Read all about Eli Lilly’s Mounjaro® (tirzepatide) and learn how it can support weight loss.
Eli Lilly’s much-anticipated Mounjaro® (tirzepatide) was approved by the FDA in May 2022 for those with type-2 diabetes. As a dual GIP- and GLP-1 receptor agonist, Mounjaro® was the first drug of its kind and has been touted as a game changer by many medical professionals in the broader fields of endocrinology and metabolic health.
Find out what makes Mounjaro® such a promising advancement in the GLP-1 class and how it can help with weight loss in patients with overweight or obesity.
Medically reviewed by: Kristin Baier, MD
What is Mounjaro® (tirzepatide)?
Like other well-known GLP-1 drugs—such as Wegovy®, made by Eli Lilly competitor Novo Nordisk—Mounjaro® is a once-weekly injectable medication that helps regulate blood sugar levels. It is indicated for use in patients with type-2 diabetes, but it may be prescribed off-label for individuals who meet certain criteria for weight loss.
Clinical trials found doses of tirzepatide effective in reducing hemaglobin A1C levels and assisting with weight loss. In addition, a 2023 study found the medication to be effecting in reducing the predicted risk of atherosclerotic cardiovascular disease, as well as improving cardiometabolic risk factors in those with obesity or overweight.
Mounjaro® is prescribed by Calibrate clinicians
Mounjaro® is one of the medications prescribed by Calibrate clinicians, if clinically appropriate, to work in conjunction with the Calibrate Metabolic Reset. Our program combines 1:1 video coaching, medication, and lifestyle changes for 10%+ weight loss or your money back (see terms).
Successful and sustained weight loss with Mounjaro® requires more than just the injection of the drug itself—it also involves intensive lifestyle interventions, many of which are difficult to manage alone.
With Calibrate, members benefit from comprehensive, one-on-one support that spans four key areas: Food intake, exercise, sleep, and emotional health.
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What's the difference between Mounjaro® and Zepbound®?
Mounjaro® is manufactured by Eli Lilly & Co., a US-based pharmaceutical company that also manufactures Zepbound®. It has been FDA-approved since 2022.
Both Mounjaro® and Zepbound® contain the same active ingredient—tirzepatide.
While Mounjaro® is currently FDA-approved for use in patients with type-2 diabetes, clinical studies show that its active ingredient is safe and effective in treating overweight or obesity. Just as it does in adults with type-2 diabetes, Mounjaro® can improve blood sugar levels in adults with insulin resistance or prediabetes—and is an effective tool for weight loss among both groups.
Is Mounjaro® approved for weight loss?
As of May 2022, Mounjaro® is FDA-approved for use in patients with type-2 diabetes mellitus and not for weight loss alone. However, there is proof that its active ingredient is safe and effective in treating overweight or obesity. Just as it does in adults with type-2 diabetes, Mounjaro® can improve blood sugar levels in adults with insulin resistance or prediabetes—and is an effective tool for weight loss among both groups.
How does Mounjaro® work?
Mounjaro® works similarly to the other drugs in the GLP-1 family, but it contains an extra molecule that may give it a slight edge.
The medication has a dual-action design, mimicking the action of not one but two incretin hormones involved in blood sugar control: Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). This unique dual action makes it the first-in-class medicine that acts on both of these receptors.
According to a press release published by Eli Lilly, “GIP is a hormone that may complement the effects of GLP-1 receptor agonists. In preclinical models, GIP has been shown to decrease food intake and increase energy expenditure therefore resulting in weight reductions, and when combined with GLP-1 receptor agonist, may result in greater effects on markers of metabolic dysregulation such as body weight, glucose and lipids.”
Why mimic incretin hormones?
Incretin hormones are released whenever food is consumed. Among other things, they help promote a feeling of fullness by delaying gastric emptying and activating the satiety centers of the brain. They also boost insulin production in the pancreas, and suppress glucagon production, both of which help normalize blood sugar.
All of this happens in a glucose-dependent manner, which means incretin hormones—or their imitators, i.e. GLP-1 and GIP receptor agonists—are unlikely to cause severe hypoglycemia.
What about your natural incretin hormones? Studies have found that people with overweight or obesity may have a reduction in incretin effects, particularly if they have had frequent weight fluctuations due to yo-yo dieting. GLP-1-type medication narrows the gap, making it easier to reach your goals and lower your metabolic set point.
Dosage & how to administer Mounjaro®
Mounjaro® (tirzepatide) is meant to be used alongside lifestyle changes, i.e. changes to food, sleep, and exercise. Like all GLP-1s, it works best when accompanied by coaching and support from trained professionals.
The recommended starting dosage of Mounjaro® is 2.5 mg delivered as a subcutaneous (under the skin) injection once per week. After 4 weeks, doses may be increased in 2.5 mg increments, as tolerated, up to a maximum of 15 mg once weekly. Doses are set and monitored by a healthcare provider and may be adjusted to help patients meet their blood sugar, weight loss, and metabolic health goals.
How to administer Mounjaro® injections
Store Mounjaro® in the refrigerator until use but avoid freezing it. Before injecting, let the medication come to room temperature for about 30 minutes.
1. Prepare the injection site: Choose an area such as your stomach, thigh, or upper arm. Clean the area with alcohol.
2. Uncap the pen: Remove the base cap of the pen. Inspect the pen and solution for any damage or particles. Do not use it if the solution is cloudy, discolored, or contains particles.
3. Place the pen against the skin: Hold the pen at a 90-degree angle to your skin.
4. Press the button: Once you hear a click, the injection has started. Keep the pen in place until the green bar stops moving, which takes about 5–10 seconds.
Take Mounjaro® on the same day each week. If you miss a dose, take it as soon as possible within 96 hours (4 days). If more time has passed, skip the missed dose and resume your normal schedule.
IT’S ABOUT BIOLOGY
NOT WILLPOWER
Traditional weight loss programs don’t work because sustainable weight loss doesn’t come from yo-yo dieting or calorie counting. It comes from improving your metabolic health. Calibrate’s One-Year Metabolic Reset helps you do just that, through a unique combination of clinician-prescribed medication, 1:1 video coaching, and lifestyle tweaks tailored to you. The result? Improved metabolic health and sustained weight loss.
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Clinical trials of Mounjaro® (tirzepatide)
Is Mounjaro® really all that special? All signs point to yes.
Results of the drug’s clinical trials made headlines even prior to its FDA approval, and for good reason: Tirzepatide has, in two separate studies, blown some of its competitors out of the water.
SURPASS-2 clinical trial
In a 2021 head-to-head trial, Eli Lilly’s Mounjaro® was found to be more effective at controlling blood sugar and helping patients lose weight than Novo Nordisk’s Ozempic® (semaglutide). This SURPASS-2 trial took place over the course of 40 weeks and participants saw, on average, A1C reductions of up to 2.30 percentage points vs. their baseline. This was compared to a 1.86 percentage point reduction achieved with semaglutide.
Perhaps even more interestingly, the same trial concluded that reductions in body weight were greater with tirzepatide than with semaglutide: Up to 5.5 kg more weight loss was seen with the former. Researchers hypothesize that this has to do with the medications’s unique dual action.
A summary published in the New England Journal of Medicine states, “In patients with type 2 diabetes, a single molecule combining the glucose-dependent insulinotropic polypeptide receptor and GLP-1 receptor agonist may have a greater effect on glucose levels and weight control than selective GLP-1 receptor agonists.”
SURMOUNT-1 clinical trial
In the widely-publicized SURMOUNT-1 trial, Mounjaro® was examined specifically for weight loss and the treatment of obesity. It did not disappoint: At week 72, average weight loss was 15.0% for those on a 5 mg dose, 19.5% for those on a 10 mg dose, and 20.9% for those on a 15 mg dose. This was compared to weight loss of only 3.1% in participants taking a placebo.
Other trials and research
In an earlier study completed in 2018, doses of Lilly’s tirzepatide were pitted against dulaglutide—a.k.a. Trulicity®—and “showed significantly better efficacy with regard to glucose control and weight loss than did dulaglutide, with an acceptable safety and tolerability profile.” Side effects with tirzepatide were similar to those of dulaglutide and, in general, well tolerated.
Other trials of Mounjaro® compared tirzepatide against a placebo or against more traditional therapies, including two long-acting insulin analogs. In all cases, tirzepatide at the highest dose of 15 mg/week has outperformed its opponents in A1C reduction and in overall weight loss.
In a 2024 study, independent researchers (not affiliated with the drug manufacturer) again concluded that tirzepatide shows greater efficacy for weight loss versus semaglutide—and, while "most adults with overweight or obesity experienced 5% or greater weight loss with treatment [of either semaglutide or tirzepatide], the benefit was greater with tirzepatide."
Is Mounjaro® (tirzepatide) available to Calibrate members?
Calibrate clinicians prescribe Mounjaro® clinically appropriate. Other GLP-1 medications currently available to Calibrate members include Zepbound®, Wegovy®, Ozempic®, Rybelsus®, Saxenda®, and Trulicity®. Your medical team will prescribe whichever medication is the best fit for you based on your unique needs, health history, and insurance coverage.
When you join Calibrate, you’ll complete a Comprehensive Health Intake, including blood work, that your Calibrate clinician will carefully review before customizing your treatment plan and prescribing your medication. You may be eligible for tirzepatide or semaglutide even if you are already taking another type 2 diabetes medication such as metformin.
If your Calibrate medical team determines that Mounjaro® is the right fit for you, they’ll walk you through all of the details on dosage, how to administer the medication, when to take it, and how it will work alongside your metabolic reset plan.
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Mounjaro® side effects
The most common side effects of Mounjaro® include:
• Nausea
• Diarrhea
• Decreased appetite
• Vomiting
• Constipation
• Indigestion
• Stomach (abdominal) pain
Keep in mind that these are not all the possible side effects. Talk to your Calibrate clinician about any side effects of Mounjaro® that become bothersome or that don’t go away.
There are no specific foods that you need to avoid when taking tirzepatide, but some find it helpful to avoid fried or fatty foods in order to minimize side effects.
If you experience any severe side effects, such as anaphylaxis or shortness of breath, please seek immediate medical care.
Important safety information about Mounjaro® (tirzepatide)
Mounjaro® (tirzepatide) is not suitable for those with type 1 diabetes, a history of pancreatitis, or specific conditions like medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Patients must be monitored for possible side effects, including pancreatitis, hypoglycemia (especially when combined with insulin), and adverse gastrointestinal reactions. Clinical oversight is essential, particularly for those with renal impairment or diabetic retinopathy.
Mounjaro® for weight loss FAQs
Key takeaways
Tirzepatide, sold under brand names Mounjaro® and Zepbound®, has proven itself a valuable drug among the broader GLP-1 class of medications for its regulation of blood sugar levels and ability to promote weight loss.
Here’s what you need to know at a glance:
• Mounjaro® (tirzepatide) is a dual GIP and GLP-1 receptor agonist and the very first medication of its class. It works similarly to GLP-1 receptor agonists like Ozempic® or Wegovy® but has a dual-action design that works on a second type of receptor: Glucose-dependent insulinotropic polypeptide (GIP).
• As of May 2022, Moujaro® is FDA-approved for use in adults with type-2 diabetes. However, there is proof that its active ingredient, tirzepatide, is safe and effective in treating overweight or obesity.
• Participants of the SURPASS-2 clinical trial of Mounjaro® (tirzepatide) saw, on average, A1C reductions of up to 2.3% vs. their baseline. The same trial also found that tirzepatide produced 5.5 kg more weight loss when compared against semaglutide.
• Calibrate clinicians may prescribe Mounjaro® to patients where clinically appropriate and insurance-eligible. You may be prescribed a different GLP-1 medication depending on your unique health history.