The prevalence of obesity is on the rise, with the incidence being as much as 41.9 percent in the US between 2017 and 2020. Being overweight or obese can lead to many complications, having the ability to negatively impact your health, wellness, and quality of life. Thankfully, several weight loss medications are currently on the market that can support individuals’ weight loss journeys.

A key feature of many of these weight loss drugs is that they have multiple indications. For example, several drugs are approved by FDA for multiple uses, such as with type 2 diabetes and weight management. Glucagon-like peptide-1 (GLP-1) receptor agonists are one such drug class that have proven efficacy both in the realm of diabetes and weight loss. Such GLP-1s include tirzepatide and semaglutide. This article will discuss each of these medications, specifically the brands Mounjaro and Ozempic, including their similarities and differences.

What is Mounjaro?

The Food and Drug Administration (FDA) approved Mounjaro (tirzapetide), a drug manufactured by Eli Lilly, for the treatment of adults with type 2 diabetes mellitus (T2DM). The Mounjaro label indicates it should be taken adjunct to exercise and diet to control blood sugar levels.


Mounjaro is the brand name for the active ingredient tirzapetide. Tirzapetide functions in the body as a glucagon-like peptide-1 receptor agonist and a glucose-dependent insulinotropic polypeptide (GIP) agonist. My mimicking the body’s endogenous GIP and GLP-1 incretin hormones, tirzapetide exerts dual pharmacologic activity at both receptors. As a GLP-1 agonist, tirzapetide activates pancreatic insulin secretion and slows gastric emptying. By slowing gastric emptying, GLP-1 agonists delay the rate in which food contents move through the body. When emptying is slowed, your appetite becomes suppressed. On the other hand, GIP helps support weight loss by causing satiety within the hypothalamus.


Because of Mounjaro’s double mechanism, it demonstrated positive results in several clinical trials in both diabetes and in weight loss. This series of studies is known as the SURPASS clinical trials, of which there are several completed and ongoing to characterize Mounjaro’s clinical profile.

It is important to note that the studies Mounjaro’s approval was based on evaluated its efficacy in diabetes, and the studies only looked at weight reductions as secondary endpoints. Thus, though trends may be seen with regards to weight, no major conclusions can be made.

These trials also evaluated Mounjaro against placebo as well as other types of medication. Let’s review some of the data:

  • SURPASS-1: Mounjaro caused weight losses of between 6.3 to 8.8 kg
  • SURPASS-2: Mounjaro caused weight losses of 5.5 kg more than semaglutide
  • SURPASS-3: Mounjaro caused average weight losses of 7.5 kg (5 mg), 10.7 kg (10 mg), and 12.9 kg (15 mg) versus an increase in 2.3 kg with degludec
  • SURPASS-4: Mounjaro had more potent weight loss compared with insulin glarigine
  • SURPASS-5: Mounjaro lowered patient weight byan average of 10.9 kg versus the placebo group that gained an average of 1.7 kg

Based on this data, it is pretty obvious that Mounjaro can be effective in decreasing weight compared with placebo or insulin. In some cases, it may even be more efficacious than certain doses of semaglutide, which is the active ingredient in Wegovy and Ozempic.


The most frequently experienced side effects with Mounjaro include nausea, vomiting, diarrhea, constipation, indigestion, suppressed appetite, and stomach pain. It also has the following warnings and precautions included in its label: allergic reactions, acute kidney injury, hypoglycemia (low blood sugar) when used with insulin, acute gallbladder disease, diabetic retinopathy, thyroid C-cell tumors, and gastrointestinal (GI) disease. Because of these risks, you should always take Mounjaro under the supervision of a healthcare provider.

What is Ozempic?

Ozempic contains the active ingredient semaglutide. The FDA has approved Ozempic for blood sugar management for the treatment of type 2 diabetes. Like Mounjaro, it should also be used in combination with a diet and exercise regimen. It is also indicated to lower one’s risk for cardiovascular events in those with type 2 diabetes and existing cardiovascular disease. However, it is often used off-label for chronic weight management.


Ozempic is similar to Mounjaro in that it is a GLP-1 agonist. By acting like GLP-1 in the body, it slows gastric emptying, delaying food transit throughout the digestive tract, thus keeping you full for longer. When you are satiated, you eat less food which can help with weight loss.


The efficacy of Ozempic’s active ingredient, semaglutide, has been demonstrated across the STEP trials, which show robust results for weight loss. Findings indicate the following:

  • STEP 1: Semaglutide 2.4 mg caused a 14.9 percent reduction in bodyweight versus a reduction of 2.4 percent with placebo
  • STEP 2: Weight decreases were 9.64, 6.99, and 3.42 percent with semaglutide 2.4 mg, 1.0 mg, and placebo, respectively
  • STEP 3: Semaglutide 2.4 caused 16.0 percent reductions in weight versus 5.7 percent with placebo, each in combination with behavioral therapy
  • STEP 4: Individuals staying on semaglutide had total reductions of 17.4 percent while those switching from semaglutide back to placebo had regains of 6.9 percent

Several other STEP trials have been published and are ongoing, but the conclusion is that semaglutide is very effective for weight loss.


The most frequently experienced side effects with Ozempic include symptoms that are GI related, including nausea, vomiting, diarrhea, constipation, stomach pain, upset stomach, gas, bloating, heartburn, and burping. There are several ways to help manage these side effects, particularly nausea, including eating slowly, not lying down after eating, eating low fat bland foods, and more. Additionally, Ozempic can cause fatigue, dizziness, headache, the stomach flu, sore throat, or a runny nose.

In addition to these common and more mild effects, Ozempic may cause more serious adverse events including pancreatitis (inflammation of the pancreas), allergy, gallbladder issues, hypoglycemia, elevated heart rate, vision problems, depression, suicidal thoughts, and kidney problems. If you experience any of these, make sure to contact your doctor right away.

Comparing Mounjaro versus Ozempic

Both of these medications, Mounjaro and Ozempic, are safe and effective in inducing weight loss, so which should you take? Before starting any medication, you should consult with a licensed healthcare provider who can select the right treatment for you and monitor you appropriately. If you have either Ozempic or Mounjaro in mind, let them know.

To summarize the differences between the two medications, let’s compare both with a chart:




Active ingredientTirzepatideSemaglutide
FDA-approved indicationTreatment of type 2 diabetes mellitus in combination with exercise and dietTreatment of type 2 diabetes mellitus in combination with exercise and diet. Lower cardiovascular risk in individuals with type 2 diabetes and cardiovascular disease.
MechanismGIP and GLP-1 receptor agonistGLP-1 receptor agonist

Single dose pen

Injection under the skin into the abdomen, upper arm, or thigh once weekly

Single dose pen

Injection under the skin into the thigh, abdomen, or upper arm once weekly

DosingStarting dose is 2.5 mg, which can be increased to a maximum 15 mg doseStarting dose is 0.25 mg, which can be increased to a maximum dose of 2 mg
Mild side effectsNausea, vomiting, diarrhea, constipation, indigestion, suppressed appetite, and stomach painNausea, vomiting, diarrhea, constipation, stomach pain, upset stomach, gas, bloating, heartburn, burping, fatigue, dizziness, headache, the stomach flu, sore throat, and a runny nose
Serious adverse effectsLow blood sugar, gallbladder issues, kidney problems, thyroid cancer risk, pancreatitis, allergyLow blood sugar, gallbladder issues, kidney problems, thyroid cancer risk, pancreatitis, allergy
EfficacyMounjaro is not approved by the FDA for weight management, but the SURPASS studies indicate it can cause weight loss. In SURPASS-2, Mounjaro caused weight losses of 5.5 kg more than semaglutide.Semagltuide, Ozempic’s active ingredient, has been studied and approved for weight management, with efficacy versus placebo as demonstrated in the STEP trials.

As you can see from this side-by-side comparison, there are not that many differences between the two medications, but there are some. Key differences include:

  • The mechanism. Mounjaro has dual action as a GIP and GLP-1 receptor agonist, while Ozempic is only a GLP-1 receptor agonist.
  • Efficacy. Studies have shown that Mounjaro may decrease weight more than Ozempic. That being said, every person is different, and just because a study shows something does not mean it will apply to you.
  • Price. The cost of Mounjaro or Ozempic will depend on your particular insurance, pharmacy, and what indication you are using the medication for. Therefore, it is difficult to compare cost between the two.

Long-term Management and Sustainability

The journey of managing weight and diabetes with medications like Mounjaro and Saxenda is not just about achieving short-term goals; it’s about sustaining these health benefits in the long run. Long-term management and sustainability are crucial for maintaining the progress made during the medication course. After discontinuation of these drugs, it’s important to integrate lifestyle changes that support ongoing health and wellness. This includes:

  • Continued Healthy Eating: Adopting a balanced diet rich in nutrients, low in processed foods, and appropriate in portion sizes can help maintain weight loss and blood sugar levels.
  • Regular Physical Activity: Consistent exercise helps in maintaining weight loss, improving insulin sensitivity, and enhancing overall cardiovascular health.
  • Regular Health Check-ups: Regular monitoring of blood sugar levels and overall health can help in early detection and management of any deviations from desired health goals.
  • Stress Management: Chronic stress can negatively impact blood sugar levels and weight. Practices like mindfulness, yoga, and adequate sleep can help manage stress.
  • Support Systems: Engaging with support groups, healthcare providers, or a nutritionist can provide the necessary guidance and motivation to stay on track.

Side Effects Management

Managing side effects is key to ensuring that patients can continue their treatment with minimal discomfort and maximum benefit. Here are some strategies to manage common side effects of Mounjaro and Saxenda:

  • Gastrointestinal Issues: Nausea, vomiting, and diarrhea are common. Eating smaller, more frequent meals, avoiding spicy and fatty foods, and staying hydrated can help. Ginger tea or ginger supplements may also alleviate nausea.
  • Injection Site Reactions: Rotating injection sites and using proper injection techniques can minimize discomfort and skin reactions. Applying a cold compress post-injection can also be soothing.
  • Fatigue and Dizziness: Ensuring adequate hydration, maintaining a balanced diet, and getting enough sleep can help manage fatigue. Standing up slowly can help reduce dizziness.
  • Low Blood Sugar: Patients should be aware of the symptoms of hypoglycemia and keep a source of fast-acting glucose handy. Regular meal times and balanced carbohydrate intake can prevent blood sugar dips.
  • Headaches: Staying hydrated, regular meals, and adequate rest can help prevent headaches. Over-the-counter pain relievers can be used as advised by a healthcare provider.

In all cases, it’s important for patients to communicate with their healthcare providers about any side effects they experience. Adjustments in dosage or additional treatments may be necessary to manage these effects effectively.

Expert Opinions

Incorporating insights from medical experts and endocrinologists, the article can provide a nuanced understanding of the effectiveness and suitability of Mounjaro and Ozempic. According to a large analysis of real-world data published by Truveta Research, Mounjaro (tirzepatide) has shown to be more effective for weight loss in overweight or obese adults compared to Ozempic (semaglutide). Patients on Mounjaro were significantly more likely to achieve substantial weight loss at various time points compared to those on Ozempic. This study aligns with clinical trial observations and the experiences of healthcare professionals.

Dr. Nick Stucky of Truveta Research emphasized the importance of this study in informing patient care, especially given the lack of head-to-head clinical trials in non-diabetic populations. The study examined health data from about 18,000 adults, finding that Mounjaro users were notably more likely to lose significant percentages of their body weight compared to Ozempic users.

Furthermore, Dr. Mopelola Adeyemo from the University of California at Los Angeles and Dr. Jennifer Cheng from Hackensack Meridian Jersey Shore University Medical Center highlighted that while both medications are effective for weight loss, Mounjaro’s dual action on GLP-1 and GIP hormones might offer an edge over Ozempic, which targets only GLP-1. However, they also noted the need for long-term cardiovascular safety data for tirzepatide, contrasting with the established data for semaglutide.

Can You Switch Between These Two Drugs?

Switching between different brands of type 2 diabetes and obesity drugs, such as Ozempic and Mounjaro, is generally considered safe when they are prescribed by a doctor for the same condition. However, dosing is an important factor to consider during the switch. If a patient starts a new medication at a higher dose than their previous one, they might experience unpleasant side effects.

Dr. Robert Kushner from Northwestern University Feinberg School of Medicine mentioned that drug shortages and difficulty finding specific dosages are common reasons for patients switching medications. Dr. Kathleen Wyne from The Ohio State University Wexner Medical Center explained that while Mounjaro and Ozempic have slightly different mechanisms, switching between them for type 2 diabetes management is feasible.

Dr. Paresh Dandona from the University at Buffalo emphasized that both drugs lower blood sugar, increase insulin sensitivity, and decrease appetite, leading to weight loss. However, Mounjaro’s strengthened effect might lead to greater weight loss. He also noted the importance of insurance coverage in the decision-making process, as off-label use might not be reimbursed.

When changing medications, it’s crucial to do so under the guidance of a healthcare provider. The side effect profiles of these drugs are similar, but transitioning from a lower dose of one drug to a higher dose of another can lead to gastrointestinal side effects. Patients should also be aware of potential allergic reactions when switching medications.

So how do I choose?

As previously mentioned, if you are looking for a weight loss medication to add into your weight management strategy, discuss first with your doctor. They will be able to review your health history, condition, age, and preferences to select the best option for you. Additionally, they can continue to monitor your treatment for side effects and efficacy and adjust it as needed.

It is also important to note that both these medications are meant to be used in combination with a caloric deficit diet and regular exercise. These two factors make the medication work best and will thus provide you with greater results.