Less than a year ago, Mounjaro, also known as tirzepatide, was a relatively unfamiliar diabetes medication for most people. However, this situation has rapidly changed, with the medication gaining substantial attention due to its remarkable effectiveness in promoting weight loss.
Dr. Reshmi Srinath, an associate professor and the director of the weight and metabolism management program at the Icahn School of Medicine at Mount Sinai in New York City, highlights the critical need for innovative pharmaceutical solutions. She emphasizes, "Given the ongoing increase in the number of individuals dealing with overweight and obesity, which is linked to more severe health complications, it is imperative to develop new medications." While some existing drugs can facilitate a modest 10% reduction in body weight, the next generation of drugs, including tirzepatide, equips healthcare professionals with significantly improved tools to assist individuals in addressing obesity and achieving weight loss.
What is Mounjaro?
Mounjaro, chemically known as tirzepatide, is an injectable medication that received FDA approval in 2022 for the treatment of Type 2 diabetes. Although it is not yet approved for weight loss, it is currently being used off-label for this purpose. Clinical trials have shown that individuals with obesity, taking Mounjaro, have experienced weight loss of approximately 20% or more of their body weight within eighteen months of starting treatment. The FDA is expected to approve the drug for weight loss before the end of the year. However, the medication will be given a different brand name than Mounjaro upon approval, according to industry insiders.
How does Mounjaro work?
Tirzepatide has a unique mechanism of action as it simultaneously activates two receptors, earning it the label of a dual-targeted or dual-agonist medicine. This dual action stimulates two hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors. While the precise mechanism is not entirely understood, tirzepatide appears to target the brain's appetite control centers, leading to a sense of fullness.
Dr. Cecilia Low Wang, an endocrinologist at UCHealth and a professor of medicine at the University of Colorado School of Medicine in Aurora, Colorado, describes this novel drug, saying, "This agent belongs to an entirely new class of medications. Its dual action not only enhances insulin release to improve glucose control but also reduces appetite, making individuals feel full and, consequently, aiding in weight loss."
Dosage for Mounjaro
As a treatment for Type 2 diabetes, the initial dosage of Mounjaro is 2.5 milligrams, taken weekly. Typically, individuals start with a 2.5-milligram dose to allow their bodies to adjust to the medication. After four weeks, the dosage is increased in 2.5-milligram increments until an effective dosage is established. The maximum weekly dosage is 15 milligrams. Each pen of Mounjaro contains a single dose of the medication in a liquid solution, which is injected under the skin of the upper arm, abdomen, or thigh.
Dr. Low Wang explains the dosing regimen, stating, "We begin with a low dose for four weeks, then incrementally increase the dosage, which seems to improve tolerability."
How much weight can you lose?
Tirzepatide has been shown in clinical trials to help people lose 15% to over 26% of their body weight, depending on the dosage.
Eli Lilly, the manufacturer of Mounjaro, conducted the SURMOUNT-3 and SURMOUNT-4 trials, which found that patients with obesity experienced a 26.6% reduction in weight over 84 weeks while taking tirzepatide. Participants in the SURMOUNT-3 trial also underwent an intensive lifestyle intervention that included a low-calorie diet, exercise, and weekly counseling sessions.
In another significant study published in the New England Journal of Medicine, tirzepatide was evaluated in adults with obesity and at least one weight-related comorbidity, excluding diabetes. The trial included more than 2,500 adults who were randomly assigned to receive a weekly subcutaneous injection of 5, 10, or 15 milligrams of tirzepatide or a placebo for 72 weeks. Participants were provided counseling to reduce caloric intake by 500 calories a day and were instructed to exercise for 150 minutes per week.
At the end of the study, those taking a 5-milligram dose experienced an average weight reduction of 15%, those taking a 10-milligram dose lost 19.5%, and those taking a 15-milligram dose saw a reduction of 20.9%. In comparison, the placebo group had an average weight reduction of 3.1%. Additionally, those taking tirzepatide showed improved cardiovascular and metabolic measures.
For someone weighing about 200 pounds, this translates to an average weight loss of approximately 28 pounds on tirzepatide, according to Dr. Srinath.
"These findings present promising new options not only for Type 2 diabetes management but also offer the potential dual benefit of blood sugar control and weight management," Srinath underscores.
While initial weight loss is typically rapid, individuals may encounter weight loss plateaus, during which their progress may temporarily stall. The duration of these plateaus can vary among individuals. Therefore, it is crucial to complement these medications with healthy eating habits and regular physical activity. Fine-tuning and adjusting your healthy lifestyle habits can provide the necessary momentum to overcome plateaus and continue making progress.
What are the side effects of Mounjaro? Common side effects of Mounjaro include:
Nausea.
Diarrhea.
Decreased appetite.
Indigestion.
Constipation.
Abdominal pain.
Vomiting.
Other serious side effects may include:
Low blood sugar.
Allergic reactions.
Kidney failure.
Severe stomach problems.
Vision changes.
Gallbladder issues.
Pancreatitis.
Intestinal obstructions, a serious and potentially life-threatening condition known as ileus.
Doctors advise against prescribing the drug for people with severe stomach problems. In rare cases, severe gastrointestinal issues - such as stomach paralysis, pancreatitis, and intestinal obstructions - may occur. Common symptoms include bloating, nausea, vomiting, abdominal pain, constipation, and breath odor. If you experience any of these signs, talk with your health care provider immediately.
Clinical studies indicate that adverse events caused treatment discontinuation in 4.3%, 7.1%, 6.2%, and 2.6% of participants receiving 5, 10, and 15-milligram tirzepatide doses and placebo, respectively.
While studies show that tirzepatide is safe overall, the long-term effects are still unknown.
As with other popular diabetes drugs used for weight loss, one of the side effects of stopping Mounjaro may include regaining weight. To avoid rebound weight gain, it's important to maintain a healthy lifestyle that includes eating a nutritious, well-balanced diet and incorporating regular physical activity into your daily routine.