Why am I not losing weight on Mounjaro?

It takes time, about 8 to 12 weeks to see a 6% to 8% weight loss in adults using Mounjaro. Other reasons include the need to follow a reduced calorie diet and exercise program, your dose may need to be increased, or side effects may affect your treatment.

How much weight should I be losing with Mounjaro?

• In long-term studies over 40 to 52 weeks, when Mounjaro was used alone or with diabetes medications, weight loss ranged from 12 lb (5.5 kg) to 25 lb (11.4 kg) in adults using the 5, 10 or 15 mg dose injected subcutaneously (under the skin) once weekly. In general, higher doses lead to greater weight loss.
• In another Phase 3 study, after 8 to 12 weeks people using tirzepatide (the active ingredient in Mounjaro) lost about 6% to 8% of their body weight on average using injection doses of 5, 10 or 15 mg per week.

Mounjaro is approved to lower blood sugar levels in patients with type 2 diabetes, alongside diet and exercise. It is not approved as a weight loss drug, but might be prescribed off-label by your doctor for this use. Off-label use means it's prescribed by your doctor for a generally accepted use, but not specifically approved by the FDA or listed in package labeling.

Your results may vary and this does not mean that your treatment is not working. Speak with your healthcare provider if you feel like you are not losing adequate weight with Mounjaro. They can provide additional information on your individual weight loss goals.

Tirzepatide, the active ingredient in Mounjaro, is FDA-approved for weight loss maintenance under the brand name Zepbound. Both products are manufactured by Eli Lilly and Co.

Six Reasons You Are Not Losing Weight with Mounjaro

1. You have not given the medicine enough time to work.

Studies have shown that it can take 6 to 8 weeks to see up to an 8% weight loss with tirzepatide. While most people will see at least a 5% weight loss with Mounjaro, not everyone will reach this goal. The research found that 89% of people using the 10 mg dose lost 5% or more of their weight at 72 weeks.

On average, people lost 19.5% of their initial weight on the 10 mg dose after 72 weeks (18 months).

Related: How long does it take for Mounjaro to start working?

2. Your dose may not be high enough yet.

• The recommended starting dose of Mounjaro is 2.5 mg injected subcutaneously (under the skin) once weekly, increasing to 5 mg once weekly after 4 weeks.
• The 2.5 mg dosage is used only for treatment initiation to help you get used to side effects.
• Doses are then increased as needed by 2.5 mg doses after at least 4 weeks on your current dose.

As an example, if you require the maximum 15 mg weekly dose, it can take up to 20 weeks (5 months) to reach this dose.

Learn more: Mounjaro dosing (in more detail)

3. You may need to change to your diet or exercise routine.

Mounjaro works best for weight loss when used with an appropriate diet and exercise routine. You may need to consume fewer calories, eat foods that are lower in fat and increase the amount of time you exercise each day.

You might want to follow the new 2024 guidelines published in Obesity that make recommendations on what to eat if you are using a weight loss medicine like tirzepatide or semaglutide.

Guidelines suggest that women taking these weight-loss drugs should eat between 1,200 to 1,500 calories per day and men should eat 1,500 to 1,800 calories each day.

For the latest see: Guidelines: What to eat when taking tirzepatide or semaglutide

Talk to your healthcare provider about these guidelines and how they may be beneficial for you. You may also benefit from a few individual sessions with a registered dietician, physical therapist or trainer to learn how to more effectively adjust your active lifestyle.

Consider using a journal to track your daily food consumption and exercise routines. If you have a friend or family member losing weight too, team up for encouragement and to help each other stay on track.

4. Side effects may be interfering with your dose or treatment.

Your doctor may further slow down how quickly you reach your target dose if you are having intolerable stomach side effects, which can be common with medicines like Mounjaro or Zepbound. In some cases, people have had to stop treatment due to these side effects.

• In studies, stomach side effects occurred in 37% to 44% of patients (20% on placebo).
• Also, 3% to 6.6% of people receiving tirzepatide stopped treatment due to digestive tract side effects like nausea, vomiting, and diarrhea compared to 0.4% of patients receiving an inactive placebo treatment. Higher doses may lead to more frequent side effects.
• The most common Mounjaro side effects include nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia (heartburn), and abdominal (stomach area) pain, which affects 5% or more patients.

This is not a complete list of possible side effects for Mounjaro. Talk to your healthcare provider about any side effect that bothers you or doesn’t go away.

Related: Side effects, warnings and precautions with Mounjaro (in more detail)

5. Other medicines you take may contribute to weight gain

People who have type 2 diabetes and are using Mounjaro for blood sugar control, weight loss or both may not lose as much weight if they are also using certain type 2 diabetes medicines.

These medicines include:

• Insulin
• Sulfonylureas like glimepiride (Amaryl), glipizide or glyburide
• Thiazolidinediones like pioglitazone (Actos) or rosiglitazone (Avandia)
• Meglinitides like netaglinide (Starlix) or repaglinide (Prandin)

These medicines can lead to a weight gain of roughly 5 to 10 lbs (2.3 to 4.5 kg) over the first year in patients with type 2 diabetes.

Talk to your healthcare provider if you have other medical conditions or take other medicines, and how this might interfere with your weight loss regimen.

Related questions

• How do Ozempic, Mounjaro, Wegovy, Zepbound compare for weight loss?
• Tirzepatide vs semaglutide: How do they compare?
• Can you get tirzepatide from a compounding pharmacy?

6. You cannot afford it

This seems so obvious, but if you can’t afford or gain access to Mounjaro, you can’t use it to lose weight.

Unfortunately, your insurance company may not cover Mounjaro for treatment of weight loss, as it is only approved by the FDA to treat type 2 diabetes. If that’s the case, ask your doctor about using Zepbound for weight loss, another tirzepatide product that is now approved by the FDA for weight loss maintenance. Because it’s approved specifically for weight loss, your drug plan may cover it.

To find out if your prescription insurance will pay for Mounjaro, contact them and ask if Mounjaro is on their formulary (a list of the drugs approved for insurance coverage), which conditions it covers, and if covered, what your cost or copay may be. If it's not covered, ask them what other drugs are covered for weight loss.

In addition, there are copay card and patient assistance programs from Eli Lilly, the manufacturer of Mounjaro and Zepbound. If you qualify, these programs can help you gain access to your medicine more affordably, whether you have insurance or not. You may pay as little as $25 for up to a 3-month supply. Contact the Eli Lilly Mounjaro patient services support center at 1-844-805-5807 to learn more.

If you have state or federal government-sponsored prescription insurance, for example, Medicare Part D, Medicaid, or TriCare contact your plan to determine your eligibility for Mounjaro.

Learn more: Is Mounjaro covered by insurance or Medicare? How do I get a $25 copay?

Why am I gaining weight?

Food and exercise

You may be gaining weight because you are not choosing the right foods or doing adequate exercise to meet your goals. You may need to limit fats and excess simple carbohydrates, like sugar and other sweets. Guidelines suggest women taking a weight-loss drug should eat between 1,200 to 1,500 calories per day and men should eat 1,500 to 1,800 calories each day.

The latest 2024 guidelines recommend the following daily eating plan for people using GLP-1 like drugs for weight loss:

• Fats: Fats should equal 20% to 35% of your day's calorie intake, with saturated fats equal to less than 10%. Avoid fried and high-fat foods due to stomach side effects associated with weight-loss drugs like GLP-1's. Healthy fats include nuts, seeds, avocado, vegetable oil (limit palm and coconut oils). Fatty fish and seafood (salmon, albacore tuna, sardines) are recommended.
• Protein: More than 60 to 75 grams/day of protein, like beans, peas, lentils, seafood, lean meat, poultry, low-fat daily products, nuts, seeds and eggs.
• Carbohydrates: Healthy carbohydrates constituting about half of your overall energy intake with added sugars limited to less than 10% of intake. Whole grains, nuts and seeds, fruits, vegetables and dairy (milk, yogurt and dairy alternatives like soy milk) are recommended.
• Fiber: Include 21 to 25 grams of fiber per day for women and 30 to 38 grams for men. Fruits, vegetables, beans, peas, lentils, nuts, seeds and whole grains are good sources of fiber. A fiber supplement can be used if a person is not able to meet fiber goals through diet.
• Hydration: Two to three liters of fluids, including water, low-calorie beverages (coffee, tea) and low-fat dairy (low fat milk, soy milk). Limit or avoid caffeine and sugar-sweetened beverages.

You may also need to increase your exercise level to most days of the week, as recommended by your healthcare provider. Aim for at least 150 to 300 minutes of moderate aerobic exercise per week.

This includes activities such as brisk walking, biking, swimming, yoga and mowing the lawn. You can split this up into 2 or 3 sessions if that's easier or more convenient. Ask your healthcare provider if you can engage in more vigorous activity.

Consider adding strength training for extra benefit and to keep your muscles strong. Try to do strength training for all major muscle groups at least two times a week. Strength training includes use of weights, weight machines, squats, planks, push ups and use of resistance bands.

Skipping doses

Also, be sure you are taking your medicine each week as prescribed. Luckily, there's a lot of leeway if you miss a dose.

• For Mounjaro, you can take the missed dose as soon as you remember it within 4 days after the missed dose. However, if more than 4 days have passed, skip the missed dose and continue your regular dosing schedule.
• Do not inject two doses within 3 days of each other.

Other options to Mounjaro

Other FDA-approved options similar to Mounjaro and Zepbound are available for use in weight loss.

• Wegovy (generic name: semaglutide) is a GLP-1 agonist that is FDA-approved for weight loss and is similar to Mounjaro and Zepbound, but works in a slightly different way.
• Semaglutide is also sold under the brand names Ozempic and Rybelsus to lower blood sugar in people with type 2 diabetes, but these brands are not approved by the FDA for weight loss.
• Some healthcare providers may prescribe these products off label for weight loss, especially if there are instances of shortages or your plan covers one drug but not the other.

How does Mounjaro work to cause weight loss?

Mounjaro works by slowing how quickly food passes through your digestive tract, making you feel full for a longer period of time. Feeling more full can help you reduce your food intake and adhere to diet changes, which can lead to weight loss. This effect may lessen over time.

It also works by lowering lower blood sugar by helping the pancreas make more insulin and lowering the amount of sugar produced by your liver. This is beneficial for people with type 2 diabetes.

In the body, Mounjaro selectively binds to and activates two receptors, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), which are natural incretin hormones that help regulate blood sugar levels.

This is not all the information you need to know about Mounjaro (tirzepatide) for safe and effective use and does not take the place of your healthcare provider’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other healthcare provider.