Wegovy Vs Mounjaro: Which Is Better For Weight Loss?

When it comes to Wegovy vs Mounjaro and which is better for weight loss, there's no one-size-fits-all answer. Both are two of the most popular once-weekly weight loss injections in the UK, and each has MHRA approval.

Research shows that both offer significant results, including weight loss, but the SURMOUNT-5 trial revealed that Mounjaro offers more weight loss than Wegovy at a standard dose. However, high doses of Wegovy (7.2 mg) increase the average weight loss achieved.

Mounjaro price increases also mean that some private patients are turning to Wegovy as a more affordable alternative.

In this guide, we'll explore Wegovy and Mounjaro in detail, so you can make the right decision for your weight loss treatment.

Please Note: This guide is intended for information only. The right choice for you depends on your medical history, long-term goals, and advice from a healthcare professional. You should always have a clinical assessment before choosing a weight loss injection.

Key Differences Between Wegovy and Mounjaro

Both medications are proven treatments to support your weight loss journey, but there are some key differences to be aware of:

How Do Wegovy and Mounjaro Work?

Wegovy and Mounjaro are both GLP-1 medications that offer appetite control and slow gastric emptying. In simple terms, you feel fuller for longer and don't have as many cravings, which supports weight loss.

However, Wegovy and Mounjaro work differently, and understanding their mechanisms can help you decide which suits your needs.

Wegovy

Wegovy (semaglutide) works by mimicking the GLP-1 hormone, which lets the brain know when you're full. By slowing the rate at which food leaves your stomach, the weight loss treatment reduces appetite and cravings, resulting in a lower calorie intake.

By regulating your brain's reward system, Wegovy can also reduce food cravings, which prevents snacking.

Mounjaro

As with Wegovy, Mounjaro (tirzepatide) also activates the GLP-1 hormone, but it has a dual-hormone mechanism. Mounjaro also activates the GIP (glucose-dependent insulinotropic polypeptide) hormone, reducing your blood sugar levels by encouraging the pancreas to release insulin.

Because of this dual mechanism, Mounjaro typically produces more weight loss at standard doses.

Wegovy and Mounjaro Weight Loss Results

Both treatments are proven to support weight loss, but studies show that Mounjaro delivers better results at standard doses. For example, the SURMOUNT-5 trial compared average weight loss in users without type 2 diabetes.

The study focused on 751 participants and monitored weight loss achieved over 72 weeks. Patients using Mounjaro weekly injections of 15 mg achieved an average 20.2% body weight reduction (50lbs), while the Wegovy group's average weight loss was 13.7% on 2.4 mg.

Further to these base results, the study also confirmed that 45% of Mounjaro and 13.7% of Wegovy users lost 25% or more of their starting weight.

While the clinical trial seems to suggest that Mounjaro is the most effective treatment, it's essential to remember that the participants were aware of the medication they were taking, and this could impact results.

SURMOUNT-5 was also funded by Eli Lilly, the manufacturer of Mounjaro, so there's also a risk of bias.

Wegovy 7.2 mg Weight Loss Injections

Higher doses of Wegovy can close the gap on Mounjaro. For example, the STEP UP trial measured average weight reductions in patients using 7.2 mg over 72 weeks. Patients achieved an average weight loss of 20.7%, similar to the average loss on 15mg of Mounjaro.

Wegovy 7.2 mg is a higher maintenance dose, typically offered to patients who tolerate the lower doses well but require more weight loss support.

Important Note on Clinical Trials

While both SURMOUNT and STEP UP can provide some insights into the average weight loss achieved by Wegovy and Mounjaro, each trial used different populations, so direct comparisons aren't reliable.

The SURMOUNT trial focused on comparing Wegovy to the standard maximum dose of Mounjaro, but higher Wegovy doses offer similar results.

Wegovy and Mounjaro Cardiovascular Evidence

Individuals with a history of heart disease should pay careful attention to the potential impacts of both Wegovy and Mounjaro.

In the SELECT trial, adults with cardiovascular disease and obesity experienced a 20% reduction in adverse cardiovascular events compared to the placebo group while using 2.5 mg of Wegovy.

Wegovy is currently the only prescription weight loss medication with this evidence, and NICE recommends it as a treatment due to its cardiovascular benefits.

If you have a history of heart disease, this is one of the most important differences between these two treatments — and one that many comparison guides overlook.

While Mounjaro has some cardiovascular data from the SURPASS-CVOT trial, it focused on people with type 2 diabetes. The medication doesn't have data for people without diabetes, but the SURMOUNT-MMO trial is currently underway.

So, if you've experienced a stroke, heart attack, or have cardiovascular disease, Wegovy currently offers more reassurance than Mounjaro.

Wegovy and Mounjaro Side Effects: How Do They Compare?

Because both treatments help you lose weight by activating GLP-1 receptors and slowing gastric emptying, they have similar side effects. These typically include reduced appetite, nausea, constipation, diarrhoea, vomiting, injection site reactions, and indigestion.

Hair loss can also be a side effect, but it's due to rapid weight loss rather than the treatments themselves.

Most patients experience these effects when first starting their treatment and during dose increases.

Serious Side Effects Include:

• Severe allergic reactions
• Gallbladder problems
• Pancreatitis
• Dehydration
• Potential risk of thyroid tumours in people with a personal or family history of medullary thyroid carcinoma or MEN2.

Some patients have also experienced euglycaemic ketoacidosis when using Mounjaro, which can occur in non-diabetics with serious GI side effects. Currently, Wegovy isn't associated with the condition.

Precautions

The MHRA has stated that both injections may impact how your body absorbs contraceptive treatments - especially pills. Patches or gels can be more effective.

You should also inform healthcare professionals that you're taking the medication if you're planning a procedure that requires local or general anaesthesia.

Tolerability and Discontinuation Rates

People tend to tolerate both medications differently, so it really depends on personal responses. However, the discontinuation rates for Mounjaro are slightly lower than Wegovy, which could suggest that users tolerate the GI effects better.

Wegovy and Mounjaro Cost in the UK

Before September 2025, Mounjaro was considered to be one of the more affordable weight loss treatments, with prices for private patients costing £150 to £180 a month. However, Eli Lilly increased the prices, which means Mounjaro is now one of the more expensive treatments (NHSBSA).

Today, private patients can expect to pay £140 to £375 a month, depending on the dose and provider. Wegovy is a more cost-effective solution for private patients today, typically costing £79 to £300 monthly depending on your dose.

While some patients can access treatments on the NHS and pay £9.90 per item, high demand and costs mean that only a select few patients can access Wegovy and Mounjaro through the NHS. The waiting times are also significant.

Which Can You Get on the NHS?

If you meet the strict eligibility criteria and are willing to wait, you may be able to access Wegovy and Mounjaro on the NHS.

Wegovy (NICE TA875) NHS Criteria

Patients using Tier 3/4 weight management services with a Body Mass Index of 35 and over or 30 with comorbidities may be able to access Wegovy. However, the maximum NICE recommended treatment plan is 2 years, and waiting times can range from six months to two years.

Mounjaro (NICE TA1026) Criteria

Mounjaro is currently available on the NHS for individuals with the highest need. This typically includes having a BMI of 40 or over, and at least 4 weight-related medical conditions. Integrated Care Boards (ICBs) decide on eligibility, but availability will increase over a 12-year rollout phase.

If you're in Scotland, Wales, or Northern Ireland, you'll need to check local availability and speak to your GP.

For many patients, private prescriptions are the quickest way to access Wegovy or Mounjaro - but this route does come with higher costs.

Who Should Choose Mounjaro?

If any of the following applies, Mounjaro might be the best solution for your individual needs and weight loss goals:

• Your main goal is maximum weight loss, and costs aren't an issue.
• You don't have a history of cardiovascular disease or adverse cardiovascular events.
• You're already using Mounjaro and are tolerating the dual hormone mechanism well.
• Mounjaro is producing good weight loss results.
• Your prescriber recommends Mounjaro based on your initial assessment.

Who Should Choose Wegovy?

Wegovy might be a more suitable treatment if:

• You're worried about the monthly costs, as Wegovy is now cheaper.
• You've experienced cardiovascular events or have heart disease, as the SELECT trial shows that Wegovy can reduce events.
• You used semaglutide medications before and tolerated them well.
• You'd prefer to avoid injectable medications (a new Wegovy pill is now available)
• Your prescriber has recommended Wegovy
• You're eligible to access it through the NHS

Switching Between Mounjaro and Wegovy

With higher prices making Mounjaro less accessible, many patients are considering transitioning to Wegovy. While you can switch between the two, it's essential to do so under medical supervision and to follow your prescriber's instructions.

If you're planning to switch from Mounjaro to Wegovy, you'll usually need to wait at least seven days before beginning treatment. However, people switching from Wegovy to Mounjaro may be able to start on a higher dose, depending on your prescriber's assessment and recommendations.

FAQs

Which is more effective, Wegovy or Mounjaro?

Both medications are proven to support weight loss, but Mounjaro has the slight edge on the standard highest maintenance dose. However, a 7.2 mg dose of Wegovy puts it level (and in some cases slightly more effective) than Mounjaro, so it's really about your dosage.

Which is cheaper in the UK — Wegovy or Mounjaro?

Since September 2025, Wegovy has been the more affordable option, leading some people to transition from Mounjaro due to these price increases. While Mounjaro costs £140 to £375 a month depending on dose, Wegovy averages at £79 to £300.

Does Mounjaro or Wegovy have better cardiovascular evidence?

Wegovy is the only medication with proven cardiovascular evidence, making it the better option for individuals with a history of heart disease. However, Mounjaro's SURMOUNT-MMO trial is currently underway, which will measure its cardiovascular benefits.

Is Wegovy available as a pill?

Yes, Wegovy is now available as a pill in the UK, with doses ranging from 1.5 mg to 25 mg. The oral treatment will be beneficial for people who don't like injections. However, you'll take it once daily, compared to once-weekly injections.

Which can I get on the NHS?

Both Wegovy and Mounjaro are available on the NHS, but subject to strict eligibility criteria. There are also significant waiting times, so many people choose private prescriptions.

Are Mounjaro vs Wegovy side effects different?

Both have similar side effects, including injection site reactions, nausea, constipation, vomiting, and diarrhoea. However, Mounjaro also carries a small risk of euglycaemic ketoacidosis in non-diabetic users.

Read more about Mounjaro Side Effects