Wegovy vs Mounjaro

Obesity and its associated health conditions, notably Type 2 diabetes, present significant challenges in the US. The annual medical costs, which reached nearly $173 billion in 2019, underscore the undeniable burden on both healthcare systems and individuals.

Pharmaceutical companies are continually researching solutions to address these challenges. However, the off-label use of drugs, including those intended for Type 2 diabetes, as weight-loss aids, raises concerns. Moreover, drug shortages aggravate the situation, further complicating access to necessary medications.

Given these challenges, this article focuses on two recently approved medications, Wegovy and Mounjaro. Through a comparative analysis, we aim to assess their effectiveness and distinguish between them to provide clarity amidst the complexities of these medications.

Key Differences Between Wegovy and Mounjaro

Parameters	Wegovy	Mounjaro
Cost (manufacturer’s suggested retail price)	$1,349.02 per package	$1,069.08 per package
Active ingredient	Semaglutide	Tirzepatide
Approved indications	Adults with obesity or overweight with weight-related conditions, and obese adolescents aged 12-17.	Adults with type 2 diabetes
Ease of use	Weekly injection	Weekly injection
Effectiveness	After 104 weeks, patients on a 2.4 mg dose saw an average weight reduction of 35 lbs.	After 104 weeks, patients on 5 mg, 10 mg, and 15 mg saw an average weight reduction of 14 lbs, 20 lbs, and 23 lbs, respectively.
Side effects	Nausea, diarrhea, vomiting, constipation, abdominal pain, and headache.	Nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion, and stomach pain.
Dosage and administration	Begins with a weekly dosage of 0.25 mg, gradually raised to 1.7 mg or 2.4 mg per week within 17 weeks.	Begins with a weekly dosage of 2.5 mg, gradually raised to 15 mg per week within 21 weeks.
Weight loss onset	4-8 weeks	28 weeks

Efficacy in Weight Loss

This part of the discussion centers on the effectiveness of Wegovy and Mounjaro in promoting weight loss.

Wegovy (semaglutide)

The latest study, called the STEP program, looked at how well Wegovy works for weight loss. People in the study were chosen based on their body mass index (BMI) and didn’t include people diagnosed with type 2 diabetes, except for STEP 2. The trials administered an experimental dose of 2.4 mg once a week through subcutaneous delivery.

Here’s what they found in the STEP trials:

• STEP 1: The study lasted for 68 weeks and examined how semaglutide compares to a placebo. Those with diabetes weren’t part of the study, but about 40–45% had prediabetes. On average, those taking semaglutide lost 33.73 lbs, while those on the placebo only lost 5.73 lbs.
• STEP 2: This trial enrolled participants diagnosed with type 2 diabetes and who were overweight or obese. It compared the standard 1.0 mg dose against the higher 2.4 mg dose and placebos over a span of 68 weeks. During this time, those receiving the higher dose of semaglutide (2.4 mg) saw more significant weight loss, with an average reduction in body weight of 21.38 lbs compared to 5.51 lbs in the standard dose group (1.0 mg) and 2.87 lbs in the placebo group.
• STEP 3: The participants in this trial were randomly assigned to receive either semaglutide 2.4 mg or a placebo, alongside intensive behavioral therapy aimed at helping them adopt a healthier lifestyle. By week 68, those taking semaglutide experienced a significant average reduction in body weight of 37.04 lbs, compared to 13.67 lbs in the placebo group.
• STEP 4: In this trial, all participants were initially given semaglutide 2.4 mg for the first 20 weeks. Afterward, they were randomly divided into groups, receiving either semaglutide or a placebo for the remaining 48 weeks. On average, those who stayed on semaglutide lost 15.65 lbs of their starting body weight by week 68, while those who switched to placebo gained 13.45 lbs.
• STEP 5: The trial compared semaglutide to a placebo, with both groups adhering to a reduced calorie meal plan and increased physical activity for two years. Those assigned to semaglutide saw a notable average weight reduction of 35 lbs by week 104, while the placebo group experienced a reduction of only 6 lbs.

Mounjaro (tirzepatide)

While the primary focus of studies on Mounjaro wasn’t weight loss, its impact on body weight was evaluated as a secondary measure.

The SURPASS phase 3 global clinical development program for tirzepatide involved five global registration trials spanning 40 to 104 weeks. These trials investigated the efficacy and safety of tirzepatide at doses of 5 mg, 10 mg, and 15 mg. Participants received Mounjaro via subcutaneous injection once weekly.

Here are the key findings from these trials:

• SURPASS-1: In a 40-week study comparing tirzepatide to a placebo among adults with inadequately controlled type 2 diabetes who relied solely on diet and exercise, participants experienced average weight reductions of 14 lbs (5 mg), 15 lbs (10 mg), and 17 lbs (15 mg) from their starting weight. In contrast, those on the placebo only saw a 2 lb reduction.
• SURPASS-2: In another 40-week study comparing tirzepatide to injectable semaglutide among adults with type 2 diabetes who were inadequately controlled with metformin alone, tirzepatide demonstrated superior weight loss outcomes. Participants experienced average weight reductions of 17 lbs (5 mg), 21 lbs (10 mg), and 25 lbs (15 mg) with tirzepatide, compared to 13 lbs with semaglutide.

However, it’s worth noting that the researchers used a semaglutide dose of 1.0 mg for comparison. In the STEP 2 trial, a higher dose of 2.4 mg resulted in an average weight loss of 21 lbs.

• SURPASS-3: In a 52-week study comparing tirzepatide to insulin degludec among adults with type 2 diabetes receiving metformin treatment with or without an SGLT-2 inhibitor, tirzepatide resulted in weight reductions for participants. On average, those taking tirzepatide experienced weight decreases of 15 lbs (5 mg), 21 lbs (10 mg), and 25 lbs (15 mg), while those on insulin degludec saw an increase in weight by 4 lbs.
• SURPASS-4: In a 104-week study comparing tirzepatide to insulin glargine among adults with type 2 diabetes who were inadequately controlled with oral antihyperglycemic medications and had increased cardiovascular risk, tirzepatide showed notable weight reductions. On average, participants receiving tirzepatide experienced weight loss of 14 lbs (5 mg), 20 lbs (10 mg), and 23 lbs (15 mg). In contrast, those treated with insulin glargine gained 4 lbs.
• SURPASS-5: During a 40-week study comparing tirzepatide to placebo in adults with inadequately controlled type 2 diabetes already on insulin glargine, with or without metformin, participants treated with tirzepatide experienced notable average weight reductions. Specifically, those receiving tirzepatide witnessed their weight decrease by an average of 12 lbs (5 mg), 17 lbs (10 mg), and 19 lbs (15 mg) from their initial weight, whereas individuals on placebo showed an increase of 4 lbs.

To summarize:

Side Effects

Before using Wegovy or Mounjaro for weight loss or diabetes control, individuals should be aware of the potential side effects associated with these medications.

Wegovy

Reported adverse reactions in adult clinical trials, with an incidence of 2% or more in Wegovy-treated patients and occurring more frequently than in placebo-treated patients, include (listed from most to least experienced):

• Nausea
• Diarrhea
• Vomiting
• Constipation
• Abdominal Pain
• Headache
• Fatigue
• Dyspepsia
• Dizziness
• Abdominal Distension
• Eructation
• Hypoglycemia in T2DM
• Flatulence
• Gastroenteritis
• Gastroesophageal Reflux Disease
• Gastritis (includes chronic gastritis, gastritis, gastritis erosive, and reflux gastritis)
• Gastroenteritis Viral
• Hair Loss

Additionally, below are the adverse reactions noted in 3% or more of pediatric patients treated with 2.4 mg Wegovy. These reactions, listed from most prevalent to least prevalent, were reported more frequently than in those given a placebo, based on a study involving 201 pediatric patients aged 12 years and older.

• Nausea
• Vomiting
• Diarrhea
• Headache
• Abdominal Pain
• Nasopharyngitis
• Dizziness
• Gastroenteritis
• Constipation
• Gastroesophageal Reflux Disease
• Sinusitis
• Urinary tract infection
• Ligament sprain
• Anxiety
• Hair Loss
• Cholelithiasis
• Eructation
• Influenza
• Rash
• Urticaria

Other side effects in adults and/or pediatric patients include:

• Acute Pancreatitis
• Acute Gallbladder Disease
• Hypoglycemia
• Acute Kidney Injury
• Retinal Disorders in Patients with Type 2 Diabetes
• Increase in Heart Rate
• Hypotension and Syncope
• Appendicitis
• Gastrointestinal Adverse Reactions
• Injection Site Reactions
• Hypersensitivity Reactions (anaphylaxis, angioedema)
• Dysgeusia
• Laboratory Abnormalities (increased Amylase and Lipase, and Liver Enzymes)

Users should also be mindful of potential risks or safety considerations associated with Wegovy, including:

• Risk of Thyroid C-Cell Tumors
• Diabetic Retinopathy Complications in Patients with Type 2 Diabetes
• Suicidal Behavior and Ideation

Mounjaro

The following are the side effects linked with Mounjaro usage in the series of placebo-controlled trials. These reactions were observed in at least 5% of patients treated with Mounjaro.

• Nausea
• Diarrhea
• Decreased Appetite
• Vomiting
• Constipation
• Dyspepsia
• Abdominal Pain

Other adverse effects involve:

• Gastrointestinal Adverse Reactions (eructation, flatulence, gastroesophageal reflux disease, and abdominal distension)
• Hypoglycemia (more prevalent when Mounjaro was administered alongside a sulfonylurea)
• Heart Rate Increase
• Hypersensitivity Reactions
• Injection Site Reactions
• Acute Gallbladder Disease
• Laboratory Abnormalities (Amylase and Lipase increase)

Additionally, there may be potential risks or safety issues that users should be informed about, such as:

• Risk of Thyroid C-cell Tumors
• Pancreatitis
• Acute Kidney Injury
• Severe Gastrointestinal Disease (including severe gastroparesis)
• Diabetic Retinopathy Complications

Key Statistics
Considering two separate studies:

• 6.8% of Wegovy patients and 1.8% of Mounjaro patients permanently stopped treatment due to adverse reactions.

• Gastrointestinal reactions resulted in treatment discontinuation for 4.3% of Wegovy patients and 7.0% of Mounjaro patients.

Active Ingredient and Mechanism of Action

Mounjaro contains tirzepatide as its active ingredient, whereas Wegovy contains semaglutide. Despite their different active ingredients, they both function by imitating gut hormones known as incretins.

Incretins play an important role in regulating insulin release from the pancreas and controlling glucose production in the liver. They also slow down the movement of food through the digestive system and influence parts of the brain that regulate appetite.

When a medication replicates an incretin, it can effectively delay stomach emptying and reduce appetite, thereby aiding in the regulation of food consumption and promoting a sense of satiety after meals.

Wegovy falls under the class of medications known as glucagon-like peptide-1 (GLP-1) inhibitors. When administered, it mimics the actions of the incretin GLP-1, helping to manage blood sugar levels and promote weight loss.

Similarly, Mounjaro also mimics GLP-1 in the body but additionally replicates another incretin called glucose-dependent insulinotropic polypeptide (GIP). As a result, Mounjaro belongs to a drug classification known as dual GIP/GLP-1 agonists.

This category of medications has shown promising results in improving blood glucose control, particularly for individuals with Type 2 diabetes, compared to traditional GLP-1 agonists.

Approved Indications

Wegovy and Mounjaro were tested in clinical trials with varying primary endpoints, leading to their distinct approved uses.

Wegovy

Wegovy is prescribed in conjunction with a reduced-calorie diet and increased physical activity for long-term weight management in two distinct populations:

1. Adults with an initial body mass index (BMI) of 30 kg/m² or higher (classified as obese) or 27 kg/m² or higher (classified as overweight) with at least one weight-related comorbid condition such as hypertension, type 2 diabetes mellitus, or dyslipidemia.
2. Pediatric patients aged 12 years and older with an initial BMI at or above the 95th percentile standardized for age and sex (classified as obese).

It’s important to note that Wegovy should not be used alongside other products containing semaglutide or any other GLP-1 receptor agonist, as the safety and effectiveness of such combinations have not been established. Additionally, Wegovy has not been studied in patients with a history of pancreatitis.

Moreover, Wegovy is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or those diagnosed with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

In specific populations:

• Pregnancy: Wegovy carries the risk of causing harm to a developing fetus. If pregnancy is detected, discontinue the use of Wegovy immediately. It is also recommended to stop using Wegovy in patients planning to become pregnant at least two months before attempting conception.
• Geriatric: In a cardiovascular outcomes trial, participants aged 75 years and older showed a higher frequency of hip and pelvis fractures while using Wegovy compared to the placebo group. The Wegovy and placebo groups in this age category reported a greater occurrence of serious adverse reactions than younger adults.

Mounjaro

Mounjaro is prescribed for adults with type 2 diabetes to help manage blood sugar levels when used alongside diet and exercise. It can be taken alone or in combination with other diabetes medications, like metformin.

Its safety and efficacy have not been established for individuals with a history of pancreatitis or those with type 1 diabetes. Additionally, there is insufficient data to determine the safety and effectiveness of Mounjaro in pediatric patients under 18 years of age.

Furthermore, Mounjaro is contraindicated in individuals with a personal or family history of MTC or MEN 2, as well as those with known hypersensitivity to the medication or any of its components.

Special precautions should be taken in specific populations:

• Pregnancy: Animal studies suggest potential fetal harm.
• Females of Reproductive Potential: Women using oral contraceptives should consider switching to a non-oral method or adding a barrier contraceptive for four weeks after starting Mounjaro and after each dose adjustment.

Dosage and Administration

Wegovy and Mounjaro vary in their formulations, routes of administration, and prescribed dosages. Patients are advised to consult their healthcare provider for instructions regarding each medication.

Wegovy

The Wegovy pen stands out as the first and only GLP-1 RA designed for chronic weight management, offering once-weekly dosing. With its single-use design, patients administer a preset dose, ensuring accuracy, and dispose of it after each use. This autoinjector includes an integrated needle for seamless administration.

Wegovy is available in clear, colorless solution form, provided in 5 pre-filled, disposable, single-dose pens, each containing varying strengths:

• 0.25 mg/0.5 mL
• 0.5 mg/0.5 mL
• 1 mg/0.5 mL
• 1.7 mg/0.75 mL
• 2.4 mg/0.75 mL

The administration of Wegovy is as follows:

Recommended Dosage in Adults

The 0.25 mg, 0.5 mg, and 1 mg once-weekly dosages are for initiation and escalation purposes only and are not approved as maintenance dosages for chronic weight management.

In adults, the recommended maintenance dosage of Wegovy is either 2.4 mg (preferred) or 1.7 mg once weekly, considering treatment response and tolerability.

Recommended Dosage in Pediatric Patients Aged 12 Years and Older

Similar to adults, the 0.25 mg, 0.5 mg, and 1 mg once-weekly dosages are for initiation and escalation purposes only and are not approved as maintenance dosages for chronic weight management.

If patients cannot tolerate the 2.4 mg once-weekly maintenance dosage, it may be reduced to 1.7 mg once weekly. Discontinuation is necessary if the patient cannot tolerate the 1.7 mg once-weekly dosage.

Mounjaro

Mounjaro is the first and only approved treatment within a distinct medication class for type 2 diabetes. It is available in pre-filled single-dose pens with clear, colorless to slightly yellow solutions, offered in various strengths:

• 2.5 mg/0.5 mL
• 5 mg/0.5 mL
• 7.5 mg/0.5 mL
• 10 mg/0.5 mL
• 12.5 mg/0.5 mL
• 15 mg/0.5 mL

Here’s how Mounjaro is administered:

The 2.5 mg once-weekly dosage doesn’t affect the blood glucose, but it helps the body get used to the medication.

Cost

Mounjaro’s list price is $1,069.08 per package, while Wegovy’s is $1,349.02 per package. Individuals’ out-of-pocket costs will vary depending on their prescription drug insurance plans and the pharmacy they buy from. Commercially insured patients may be eligible for either the Mounjaro Savings Card program or the Wegovy Savings Offer.

For those who do not qualify for either program, purchasing medication from Canadian pharmacies like Pharma Giant presents an alternative solution.

At Pharma Giant, customers can save up to 90% on prescription medications, including Mounjaro. Additionally, customers can benefit from additional discounts and promotions, particularly when ordering larger quantities.

New customers can take advantage of the coupon code PGSAVE10, which provides a 10% discount on their initial order. Pharma Giant also ensures convenient service with expedited delivery, typically within 3-5 business days.

Weight Loss Onset

The onset of action of Wegovy versus Mounjaro varies based on individual response, health conditions, and treatment goals.

Both medications effectively manage weight and improve blood sugar levels in type 2 diabetes patients. However, their slightly different mechanisms of action may impact their speed of action.

Wegovy

Wegovy requires time to take effect, typically reaching a steady state in the body after 4-5 weeks. This state ensures consistent levels of the drug in the body, preventing fluctuations.

Clinical trials have shown that weight loss begins almost immediately following Wegovy. On average, patients using semaglutide experience a 5% reduction in body weight after one month and an 8% reduction after two months.

In another study, adults on Wegovy lost an average of 15% of their body weight after one year, compared to a 2.5% weight loss in those taking a placebo.

Mounjaro

Though not approved for weight management, significant weight loss was observed in adults during 40 and 52-week Phase 3 trials of Mounjaro. Participants experienced an average reduction of 25 lbs. Higher Mounjaro doses led to more substantial weight loss but also increased gastrointestinal side effects.

Smaller Phase 1 studies from the SURPASS program showed notable weight reduction at 28 weeks, with Mounjaro users experiencing greater weight and fat mass reductions compared to those on injectable semaglutide 1 mg and placebo. Specifically, Mounjaro users exhibited more pronounced weight loss.

Wrap-Up

While both medications share the commonality of being administered weekly via subcutaneous injection, their approved indications differ significantly. Mounjaro is used for managing type 2 diabetes, whereas Wegovy is for weight management.

Additionally, they belong to distinct drug classes. Mounjaro falls under the category of GIP/GLP-1 agonists, while Wegovy is classified as a GLP-1 agonist. Their mechanisms differ slightly, with Wegovy mimicking GLP-1 and Mounjaro targeting both GLP-1 and GIP incretins.

Moreover, the active ingredients in these medications differ, with Wegovy containing semaglutide and Mounjaro containing tirzepatide.

Given these differences, individuals should consult healthcare providers to determine the most suitable option based on their health conditions and needs.

Frequently Asked Questions