Wegovy vs Mounjaro: Which Weight Loss Injection Is Right for You?

The National Health Service (NHS) confirms that around 1 in every 4 adults in the UK is living with obesity. While diet and exercise may work for some people, others need additional support to lose weight. Weight-loss treatments such as Mounjaro and Wegovy offer this kind of help.

Doctors have approved these treatments for weight-loss support in some people. However, they can lead to significant changes in the body and quality of life. In the case of Mounjaro vs. Wegovy, the right option depends on your needs and qualifications.

In this guide, we’ll break down everything you need to know about Wegovy vs Mounjaro, including how they work, clinical results, side effects, who they're suitable for, and how to access them in the UK. Let us at Curely help you make a confident, informed decision for your weight-loss journey.

Wegovy vs Mounjaro: Mechanism of Action

Wegovy and Mounjaro are effective weight-loss medications available by prescription in the UK and other parts of the world. These weekly injections are prescribed to help people lose weight when lifestyle changes alone aren't enough. While both are weight loss injections, Mounjaro and Wegovy have key differences.

Semaglutide: Active Ingredient in Wegovy

Wegovy injection contains semaglutide, a GLP-1 receptor agonist. GLP-1 (glucagon-like peptide-1) is a class of medications that mimics a naturally occurring hormone that helps regulate appetite and food intake. When semaglutide mimics this hormone:

• It reduces hunger by acting on brain receptors that regulate appetite.
• It slows down gastric emptying, so you feel full for longer.
• It helps stabilise blood sugar levels, which is beneficial for people with insulin resistance.
• It reduces the risk of major cardiovascular events (heart attack and stroke).
• It can help protect kidney function and slow the advancement of chronic kidney disease in people with Type 2 diabetes.
• It can improve fatty liver disease.

This makes Wegovy effective at supporting healthy weight loss by reducing calorie intake without relying on willpower alone.

Tirzepatide: Active Ingredient in Mounjaro

Mounjaro is a similar weight-loss medication containing tirzepatide, a dual agonist that targets both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptors.

This dual action means:

• GIP enhances the effects of GLP-1, offering better appetite control.
• It helps to regulate blood sugar.
• It may increase metabolic rate, making it potentially more effective for weight management.
• GIP helps the body break down and utilise stored fat more efficiently.

Mounjaro vs Wegovy Biological Differences

Wegovy's active ingredient targets only GLP-1 receptors, while Mounjaro's active ingredient is a dual agonist. Both will help you eat fewer calories.

Mounjaro, however, stimulates two hormone pathways, making it more effective at reducing appetite and improving insulin sensitivity. It's beneficial for people who have weight-related health conditions such as insulin resistance or type 2 diabetes.

Wegovy vs Mounjaro For Weight Loss: Who Loses More?

According to the SURMOUNT-1 clinical trial, published by Eli Lilly in 2022, Mounjaro has shown up to 22.5% weight loss over 72 weeks. This means someone with a starting weight of 100kg could potentially lose over 22kg.

On the other hand, STEP 1 clinical trials showed Wegovy achieved an average weight loss of around 14–19% of body weight over a similar trial period (Aronne et al., 2025). Plus, according to a 2026 article by the Medicines and Healthcare products Regulatory Agency on GOV.UK, the recent introduction of the 7.2mg Wegovy dose can lead to around 20% weight loss.

Both Wegovy and Mounjaro can support weight loss when you combine them with a healthy diet and exercise plan. As for maintenance doses, a good prescribing clinician can determine the maximum maintenance dose that will support your results.

Who Should (and Shouldn’t) Use Mounjaro and Wegovy

Weight loss injections are good for treating obesity, but they aren’t suitable for everyone. Here's what to know about eligibility for effective weight loss treatments.

Best Candidates for Wegovy

• People with a BMI (body mass index) ≥30, or ≥27 with weight-related medical conditions such as high blood pressure, type 2 diabetes, sleep apnoea, and high cholesterol.
• People who need steady weight loss.

Important to Note: Wegovy may be more appropriate for people starting their first weight-loss treatment.

Best Candidates for Mounjaro

• People with a body mass index (BMI) ≥30, or ≥27 with weight-related conditions such as type 2 diabetes or insulin resistance.
• People with a lower BMI switching from another GLP-1 medication under medical supervision.
• People who need more aggressive weight loss support.
• People who have not achieved results with GLP-1-only medications.

Important to Note: Mounjaro may be preferable for people with blood sugar concerns and more weight to lose.

Contraindications & Precautions

Wegovy and Mounjaro are not suitable for:

• People with a personal or family history of medullary thyroid carcinoma
• Those with multiple endocrine neoplasia syndrome type 2 (MEN 2)
• Patients with a history of pancreatitis
• People who are or are planning to become pregnant soon
• Patients with type 1 diabetes
• Those with severe gastrointestinal disease
• People with a history of gallbladder issues
• Patients with severe kidney issues

Note that final suitability often depends on what a clinician or doctor advises. Always consult a healthcare provider before starting Wegovy or Mounjaro to promote weight loss. 

Our team is here to help when you're ready. Contact us to discuss your options.

Wegovy vs Mounjaro Side Effects

Prescription weight loss medications can have side effects even in people who are ideal candidates. Wegovy and Mounjaro share similar side effects because they both work by slowing down your digestion and affecting your brain's hunger signals for reduced calorie intake. Both injections can cause:

• Nausea: It often feels like a heavy stomach, stomach discomfort, or motion sickness.
• Vomiting: Usually happens if you eat too much or eat high-fat foods that sit in your stomach too long.
• Diarrhoea and/or Constipation: Your gut is moving at a different speed, which can lead to either end of the spectrum.
• Headaches: Often because of dehydration and your body adjusting to lower blood sugar levels.
• Fatigue: Some people feel wiped out or sleepy, especially in the first few months.
• Sulphur Burps: A rotten egg-tasting burp caused by food sitting in the stomach longer than usual.
• Heartburn/Reflux: Because food stays in the stomach longer, acid is more likely to creep up.

These side effects often reduce over time as your body adjusts to the medication. Your prescribing doctor can discuss ways to ease these effects before starting treatment.

Serious but Rare Risks

In rare cases, Mounjaro and Wegovy cause serious side effects. They’re rare but include:

• Pancreatitis, which presents as severe abdominal pain that radiates to the back.
• Low blood sugar, which presents as shakiness, sweating, confusion, or dizziness, especially in people taking other diabetes medications.
• Gallbladder issues.
• Allergic reactions.

These risks are uncommon, so if you notice them, seek immediate medical attention if you're taking Mounjaro or Wegovy.

Tips for Managing Mounjaro or Wegovy Side Effects

• Start with the lowest dose and gradually increase to the maximum dose as your prescribing practitioner advises.
• Eat smaller meals because food stays in your stomach longer.
• Avoid high-fat or greasy foods as they can ferment the longer they stay in your stomach.
• Stay hydrated to avoid headaches and fatigue.
• Eat more protein to protect your muscle mass.
• Stop eating before you're full.
• Avoid carbonated water and fizzy drinks to prevent discomfort from extra gas in the stomach.

Mounjaro and Wegovy Costs in the UK

Currently, Wegovy and Mounjaro are available via private clinics and selected NHS pathways for people who meet strict criteria. Curely offers quick access to both medications via online consultation and prescription.

Wegovy costs per month in the UK vary, usually starting at an average of £130 for the 0.25 mg starter pack. Mounjaro is more expensive, with an average starting price of £140 for the 2.5 mg pack. At Curely, we offer more affordable rates when you subscribe to our service.

Wegovy vs Mounjaro: Which Is Right for You?

Choose Wegovy if you’re looking for:

• A GLP-1 treatment
• Sustainable fat loss
• A starter option for prescription weight loss injections
• A treatment that manages blood sugar levels
• Weight loss support that can reduce the risk of major cardiovascular events
• A treatment plan that can help protect kidney function and improve fatty liver disease.

Choose Mounjaro if you want:

• Up to 22% body weight loss
• Support with blood sugar and insulin resistance
• A newer, dual-agonist mechanism for enhanced effect
• Treatment that helps the body break down and utilise stored fat more efficiently

Mounjaro vs Wegovy Comparison Table  

Alternative Weight Loss Treatments to Wegovy and Mounjaro

If you cannot take Mounjaro or Wegovy, there are other medical alternatives, including:

Saxenda (Liraglutide)

Saxenda was one of the first weight-loss medications available in the UK. Similar to Wegovy, it is a GLP-1 agonist, but it must be injected daily rather than weekly. It helps regulate blood sugar levels and suppresses appetite to support your weight loss goals. Saxenda offers an average weight loss of about 8–10%.

Oral Medications

If you prefer to avoid needles, then you should consider weight loss pills. There are several approved in the UK, with Orlistat being a good choice. It's available as Xenical or Alli; Alli is the only over-the-counter option.

Orlistat works in the gut by blocking about 25% of the fat you eat from being absorbed. It does not affect appetite and requires a strictly low-fat diet to avoid oily digestive side effects such as oily or greasy stools, and gas with an oily discharge.

Even over-the-counter options can affect your well-being if you don't have the right knowledge. If you choose these alternatives, only use them under the right medical guidance.

Wegovy vs Ozempic: Is Wegovy the Same as Ozempic?

When it comes to Ozempic vs Wegovy, both contain semaglutide, but Wegovy is licensed specifically for weight loss at higher doses, while Ozempic is primarily for treating type 2 diabetes.

Curely: Trustworthy Online Pharmacy for Mounjaro and Wegovy

We're a UK-licensed online pharmacy offering medically approved Wegovy and Mounjaro weight-loss treatments. With a strong focus on safety and discretion, we provide:

• Short and effective online consultations, no in-person GP appointments
• Free delivery on all orders over £20
• Discreet, unbranded packaging for your privacy
• UK-approved medication dispensed by certified professionals
• Ongoing support to guide your treatment

Once you complete your online consultation, you will receive your medication discreetly and securely. We also offer insight into common questions, such as the highest maintenance dose, risk factors, moving into higher doses, maintaining results after your final dose, and safety for people with severe illness. Start your consultation today and take a confident step toward your goals.

FAQs

Is Mounjaro Better Than Wegovy for Weight Loss?

SURMOUNT-5 clinical trials show Mounjaro may lead to greater weight loss than Wegovy, with up to 22.5% body weight reduction compared to Wegovy’s 14–19%.

What is the Downside of Wegovy?

Some users experience gastrointestinal side effects such as nausea or vomiting, as well as diarrhoea and constipation.

Why Do People Switch From Wegovy to Mounjaro?

People often switch to Mounjaro when Wegovy doesn’t deliver the desired results, or if they need enhanced blood sugar control and appetite suppression.

What is the Difference Between Wegovy and Mounjaro Doses?

Wegovy doses range from 0.25 mg to 7.2mg weekly, while Mounjaro doses range from 2.5 mg to 15 mg weekly.

Conclusion

Wegovy and Mounjaro both offer clinically proven prescription-only solutions for those who struggle to lose weight with traditional methods. Your choice will depend on your medical history, weight-loss goals, any additional benefits you want, and how your body responds to the medication.

If you choose weight management with Wegovy or Mounjaro, always get a prescription and purchase the injections from approved, trustworthy sources. Also, make sure you do so under a licensed clinician. Take the first step toward your healthier weight today with trusted support from Curely.

References

• Aronne, L. J., Horn, D. B., le Roux, C. W., Ho, W., Falcon, B. L., Gomez Valderas, E., ... & Dunn, J. P. (2025). Tirzepatide as compared with semaglutide for the treatment of obesity. N Engl J Med, 393(1), 26-36.
• Lilly’s Tirzepatide Delivered up to 22.5% Weight Loss in Adults with Obesity or Overweight in Surmount-1. (2022, 28/04/22) Eli Lilly and Company.
• Medicines and Healthcare products Regulatory Agency. Medicines Regulator Approves up to 7.2mg Dose of Semaglutide (Wegovy) for Patients with Obesity Only. (2026, 16/01/26) GOV.UK.
• National Health Service. Overview - Obesity. (2023, 15/02/23) NHS.
• Toliver, Joshua C, et al. Real-World Weight Loss among Patients Initiating Semaglutide 2.4 Mg and Enrolled in Wegotogether, a Digital Self-Support Application. (2025, 06/08/25) Advances in Therapy, U.S. National Library of Medicine. 
• Wilding, John  P.H., et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. (2021, 10/02/21) The New England Journal of Medicine, NEJM.