There’s a new option on the market for patients seeking treatment with a GLP-1-type drug: 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® is the first drug of its kind and has been touted as a game changer by many medical professionals in the broader field of endocrinology and metabolic health.
Find out what makes Mounjaro® such a promising advancement in the GLP-1 class and what clinical trials thus far can tell us about its ability to help with weight loss in patients with overweight or obesity. Read on to learn more.
What is Mounjaro® (tirzepatide)?
Like other well-known GLP-1 drugs—such as Wegovy®, made by competitor Novo Nordisk—Mounjaro® is a once-weekly injectable medication that helps regulate blood sugar levels. Currently, it is indicated for use in patients with type 2 diabetes, but it shows promise as a weight-loss drug as well.
Clinical trials found doses of tirzepatide effective in reducing hemaglobin A1C levels and assisting with weight loss. Early data suggests that it may even reduce the likelihood of cardiovascular events such as heart attack or stroke, though a trial tackling this question has not yet concluded.
Mounjaro® is meant to be used alongside lifestyle changes, i.e. changes to food, sleep, and exercise. It is expected that the drug will work best when accompanied by coaching and support from trained professionals.
The recommended starting dosage of Mounjaro® is 2.5 mg. 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 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 agonism, may result in greater effects on markers of metabolic dysregulation such as body weight, glucose and lipids.”
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 medication narrows the gap, making it easier to reach your goals and lower your metabolic set point.
Mounjaro® vs. other GLP-1-type drugs for weight loss: Results of clinical trials
Results of the recent clinical trials of Mounjaro® have been making headlines even prior to the drug’s FDA approval, and for good reason: Tirzepatide has, in two separate studies, blown some of its competitors out of the water.
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 drug’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 agonism may have a greater effect on glucose levels and weight control than selective GLP-1 receptor agonists.”
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.
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.
Tirzepatide availability: Is Mounjaro® available to Calibrate members?
Mounjaro® recently (as of June 2022) began to be distributed across pharmacies in the USA. Distribution can take time, but Calibrate doctors are now prescribing this medication where available and clinically appropriate. Having new, even more effective tools for our members is incredibly powerful and will continue to accelerate the way we change the way the world treats weight.
Other GLP-1 medications currently available to Calibrate members include Wegovy®, Ozempic®, Rybelsus®, Saxenda®, and Trulicity®. Calibrate doctors will prescribe whichever medication will work best for you based on your unique needs and health insurance coverage.
These GLP-1 medications make it easier to lose weight and stick to healthy habits. However, they're not a “weight loss drug” on their own: GLP-1s must be used in combination with other tactics to support metabolic health and avoid weight regain. These tactics may include modifications to what you eat, how and when you exercise, and other healthy lifestyle changes.
Calibrate’s Metabolic Reset combines GLP-1 medication with evidence-based lifestyle recommendations—the Four Pillars of Metabolic Health—to help participants maximize their success. These pillars include:
- Food
- Sleep
- Exercise
- Emotional health
By learning to eat more whole foods and fewer fast-digesting carbohydrates, improving sleep quality, participating in exercise that you actually enjoy, and managing stressors, you’re setting up both your mind and body for real results. With this foundation in place, GLP-1s can work even more effectively to reduce high blood sugar and help you lose weight.
When you join Calibrate, you’ll complete a Comprehensive Health Intake, including blood work, that your Calibrate doctor will carefully review before customizing your treatment plan and prescribing your medication. You may be eligible even if you are already taking another type 2 diabetes medication such as metformin.
If your Calibrate medical team determines that Mounjaro® or another GLP-1 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.
Ready to get started with Calibrate? Find out if you’re eligible today.
Footnotes
- https://www.clinicaltrials.gov/ct2/show/results/NCT04255433
- https://pubmed.ncbi.nlm.nih.gov/23859800/
- https://www.nejm.org/doi/full/10.1056/NEJMoa2107519
- https://www.nejm.org/doi/full/10.1056/NEJMoa2107519
- https://pubmed.ncbi.nlm.nih.gov/30293770/
- https://diabetes.medicinematters.com/tirzepatide/type-2-diabetes/a-quick-guide-to-the-surpass-and-surmount-trials/18478154
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