
Mounjaro combines two hormonal pathways to help regulate both blood sugar and appetite, leading to weight loss through multiple mechanisms:
GLP-1 Agonist (Glucagon-Like Peptide-1): GLP-1 is a hormone involved in regulating blood sugar levels and appetite. When you eat, GLP-1 helps lower blood sugar by enhancing insulin secretion and inhibiting glucagon (a hormone that raises blood sugar). It also slows gastric emptying, which can lead to increased feelings of fullness (satiety).
Medications like semaglutide (Ozempic, Wegovy) are GLP-1 agonists and have been shown to promote weight loss by reducing hunger and increasing satiety.
GIP Agonist (Gastric Inhibitory Polypeptide): GIP is another hormone involved in glucose metabolism. Tirzepatide (Mounjaro) is the first medication to combine both GIP and GLP-1 receptor activation, and early studies suggest that this dual action may enhance weight loss beyond what GLP-1 agonists alone can achieve.
GIP has been shown to improve insulin sensitivity and promote fat burning.
The amount of weight loss you can expect with Mounjaro depends on factors like your starting weight, your diet, and how your body responds to the medication. However, clinical trials show that:
- 15-22% weight loss (in clinical trials for obesity) is typical over 72 weeks, especially at higher doses (10-15 mg).
- In people with type 2 diabetes, weight loss is typically in the range of 5-10%, though some people may lose more.
This level of weight loss is significant and can have a positive impact on overall health, reducing risks associated with obesity, such as heart disease, high blood pressure, sleep apnea, and diabetes.
Other benefits of Mounjaro:
In addition to weight loss, Mounjaro has shown several other potential benefits, especially in individuals with type 2 diabetes:
- Improved blood sugar control: Mounjaro helps regulate blood glucose by improving insulin sensitivity and lowering blood sugar levels.
- Reduced cardiovascular risk: Some studies suggest that Mounjaro may reduce the risk of cardiovascular disease, which is important for those with obesity or diabetes.
- Decreased appetite: As with other GLP-1 agonists, Mounjaro reduces hunger and increases satiety, which makes it easier to adhere to a calorie-restricted diet.
While Mounjaro is generally well-tolerated, it can cause some side effects, particularly in the digestive system. Common side effects include:
- Gastrointestinal symptoms:
- Nausea, vomiting, diarrhea, abdominal pain, and constipation are the most commonly reported side effects.
- These symptoms often improve over time, especially as your body adjusts to the medication.
- Low blood sugar (hypoglycemia): While Mounjaro doesn’t typically cause hypoglycemia on its own, it can increase the risk when used with other blood sugar-lowering medications, such as insulin or sulfonylureas.
- Injection site reactions: Some people may experience redness, pain, or swelling at the site of the injection.
Serious side effects are rare but can include:
- Pancreatitis (inflammation of the pancreas): If you experience severe abdominal pain, vomiting, or nausea, you should seek medical attention immediately.
- Thyroid tumors: Animal studies have shown an increased risk of thyroid C-cell tumors with drugs like Mounjaro, but it is unclear if this applies to humans. Mounjaro is not recommended for people with a personal or family history of medullary thyroid cancer or Multiple Endocrine Neoplasia syndrome type 2.
- The weight loss effects of Mounjaro have been a key focus of clinical trials. Studies, particularly those in people with obesity or type 2 diabetes, have shown significant weight loss results. Here are the key findings:
Clinical Trials:
In the SURPASS trials (the clinical trials that studied Mounjaro for type 2 diabetes), patients with type 2 diabetes who were treated with Mounjaro experienced significant weight loss compared to those on placebo or other diabetes medications. - In a SURPASS-2 trial, patients on Mounjaro lost an average of 12-15% of their body weight over a 72-week period, which is much higher than other diabetes medications or GLP-1 agonists alone.
Weight Loss in Non-Diabetic Patients:
- In a Phase 3 trial for obesity (without diabetes), Mounjaro was shown to promote substantial weight loss. Participants taking higher doses of Mounjaro lost an average of 15-22% of their body weight after 72 weeks.
- This level of weight loss is among the highest seen with prescription medications for obesity, comparable to semaglutide (Wegovy), which is considered one of the most effective medications for weight management.
Prepare the Mounjaro Pen Wash your hands thoroughly with soap and water.
Check the pen: Ensure that your Mounjaro pen is not expired and that it has been stored correctly. It should be kept in the refrigerator until you begin using it. Once in use, you can store it at room temperature for up to 21 days (72 hours for the 12.5 mg and 15 mg doses).
Inspect the medication: The solution should be clear and colorless. Do not use the pen if the solution is cloudy, discolored, or contains particles.
Attach the Needle
- Remove the pen’s cap: The Mounjaro pen has a protective cap that you will need to remove.
- Attach a new needle: Take a new needle from its package and remove both the inner and outer needle caps.
- Screw the needle onto the pen: Twist the needle onto the pen until it is securely attached.
Prime the Pen
Priming the pen ensures that the needle is ready to deliver the full dose and removes any air bubbles.
- Hold the pen with the needle pointing up.
- Turn the dose selector to the lowest dose (usually 0.25 mg). This may be the initial starting dose, but always follow your doctor’s instructions for your prescribed dose.
- Press the injection button until you see a drop of medicine appear at the tip of the needle. This confirms that the pen is ready to use.
- If no drop appears, repeat the priming process once more to ensure proper priming.
Set the Dose
- Turn the dose selector to the correct dose as prescribed by your doctor. Mounjaro is available in different strengths, including 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg doses. Your healthcare provider will guide you on which dose to start with and when to increase it.
- Check the dose counter: Ensure the number displayed on the pen matches the dose you’re supposed to take.
Choose the Injection Site
- Mounjaro can be injected into areas with fatty tissue, such as:
- Thigh (outer area)
- Abdomen (avoiding a 2-inch area around the belly button)
- Upper arm (back or outer side of the upper arm)
It is important to rotate injection sites weekly to avoid irritation and discomfort. Do not inject into the same spot two weeks in a row.
Inject the Medication
- Pinch the skin around the injection site to lift a fold of tissue.
- Insert the needle at a 90-degree angle (straight in) to the skin.
- Press the injection button fully to deliver the medication.
- Hold the button down for about 5-10 seconds to ensure the full dose is administered.
- Release the skin pinch and remove the needle from your skin.
Dispose of the Needle
- After the injection, remove the needle from the pen by unscrewing it.
- Dispose of the used needle in a sharps container. Do not throw used needles in the trash.
- Recap the pen and store it according to the manufacturer’s instructions. If you are using it within the 21-day window, it can be kept at room temperature. Otherwise, store it in the refrigerator.
Record Your Injection
- Track your injections by noting the date and the area where you injected. This will help you rotate injection sites each week and keep track of your dosing schedule