Wegovy vs. Mounjaro (semaglutide vs. tirzepatide)

Both Mounjaro and Wegovy are effective treatments that reduce your appetite and support weight loss over time. However, Mounjaro is only available as a once-weekly injectable medication, while Wegovy is available as both a once-weekly injection and a once-daily pill.

In this article, we’ll break down the key similarities and differences between Mounjaro and Wegovy, what their side effects are, and which might be best for you.

Key points

• Mounjaro contains tirzepatide, while Wegovy pills and injections contain semaglutide.
• With the release of the maximum 7.2mg dose, Wegovy now shows similar weight loss results to Mounjaro for many patients.
• Side effects are similar, so choosing between them depends on individual suitability, response, and preference.

What is Mounjaro?

Mounjaro is a once-weekly injectable medicine used for weight management. It works by mimicking the natural gut hormones that regulate appetite and blood sugar, helping people feel fuller for longer. It's prescribed alongside lifestyle changes, like a healthy diet and increased physical activity.

What is the active ingredient in Mounjaro?

The active ingredient in Mounjaro is tirzepatide. Tirzepatide is a dual-action GLP-1 and GIP, meaning it targets two gut hormone pathways involved in appetite and glucose regulation. This dual action distinguishes it from single-hormone treatments like Wegovy.

What doses does Mounjaro come in?

Mounjaro is available in different weekly doses to allow for gradual dose escalation to help your body get used to the medication. The available strengths are:

• 2.5mg
• 5mg
• 7.5mg
• 10mg
• 12.5mg
• 15mg

2.5mg

2.5mg is the starting dose for Mounjaro. It’s not designed to deliver significant weight loss straight away. Instead, it gives your body time to adjust to the medication and helps to reduce the likelihood of stomach and digestive side effects.

5mg

After 4 weeks, your dose will typically increase to 5mg once a week if you’ve tolerated the starting dose well.

7.5mg

7.5mg is an intermediate step in the titration process, which is just the gradual increase in your dose over time. If you found that 5mg isn’t giving you enough support with appetite control, then this step bridges the gap before moving to higher doses.

10mg

10mg is a common maintenance dose for many people. This is the dose most people will start to see suppression if they haven’t already on the lower doses. If your weight loss is steady and you're tolerating Mounjaro well at this strength, your prescriber may recommend staying here rather than increasing further. It’s important to note that you don’t always need the highest dose to see good results.

12.5mg

If you need a little more support with appetite suppression and you’re tolerating treatment well, your prescriber might step you up to 12.5mg. Like all dose increases, this would only happen gradually and with your progress in mind.

15mg

15mg is the highest licensed dose of Mounjaro. That said, not all patients need this strength to achieve meaningful weight loss, so 15mg won’t be the goal for everyone. It’s there simply as another option for those who need that extra layer of support.

What dose do you start losing weight with?

Weight loss can begin on lower doses of Mounjaro, including 5mg, once appetite suppression starts to kick in. The starting dose (2.5 mg) is not intended as a weight loss dose, but to ease the body into the medication.

What are Wegovy injections?

Wegovy is a once-weekly injectable medicine used for weight management. It works by mimicking the natural hormone GLP-1, which regulates appetite and food intake. This helps people feel fuller for longer and reduces overall calorie intake when used alongside lifestyle changes.

What is the active ingredient in Wegovy?

The active ingredient in Wegovy is semaglutide, which mimics the action of the natural hormone GLP-1. It increases feelings of fullness and helps to reduce calorie intake through appetite regulation.

What doses do Wegovy injections come in?

Wegovy is available in weekly doses that are increased gradually to allow your body to adjust to treatment. The available strengths are:

• 0.25mg
• 0.5mg
• 1mg
• 1.7mg
• 2.4mg
• 7.2mg

0.25mg

0.25 mg is the starting dose for most people on Wegovy. Like Mounjaro's starting dose, it's not designed to drive weight loss straight away. It's about giving your body time to adjust to the medication and keeping early side effects, like nausea, to a minimum.

0.5mg

After 4 weeks, your dose will typically increase to 0.5mg if you've been tolerating treatment well. It's a small step up, but it starts to build on the appetite-suppressing effects of the medication.

1mg

1mg is an intermediate dose that continues to gradually increase your appetite suppression. Titrating slowly like this helps your body to adapt without becoming overwhelmed by side effects.

1.7mg

1.7mg is a further step-up in the titration process, continuing to build on the appetite-suppressing effects of the medication. Depending on how you respond, your prescriber may recommend moving to 2.4 mg or, for some people, going further still. However, many people can maintain their weight on 1.7mg.

2.4mg

2.4mg is one of the recommended maintenance doses for most patients. But not everyone needs to reach this dose if your appetite and weight are already well controlled at a lower strength.

7.2mg

7.2mg is the highest dose option available for Wegovy. To be considered for this strength, you'd need to have been on Wegovy for at least 20 weeks and be tolerating treatment well at your current dose.

This dose comes as 4 single-use pens (1 pen, once a week), each pre-filled and ready to inject. There's no needle to attach, either. As with any increase, your prescriber will only recommend this strength if it's the right fit for you based on your progress and how your body has responded to treatment so far.

At what dose do you start losing weight?

Weight loss usually begins at 0.5mg or 1mg, as you start to notice appetite suppression, but everyone is different.

The 0.25mg starting dose is designed for tolerability, not for weight loss. Dose increases depend on your response to the medication and what side effects you could experience.

What are Wegovy tablets?

The Wegovy pill is a once-daily tablet for weight loss, containing semaglutide, the same active ingredient as the Wegovy injection. It’s also made by Novo Nordisk, and was approved by the MHRA in June 2026 before launching in the UK the following month.

The tablet works thanks to a carrier molecule that protects the semaglutide long enough to be absorbed into your bloodstream, where it then works just like the injection.

This helps you feel fuller for longer, reduces cravings, and makes it easier to eat less. It works best alongside healthy eating and regular movement, not as a quick fix on its own.

The doses of the Wegovy pill

There are 4 available doses of the Wegovy pill, and you'll build up gradually to help your body adjust:

• 1.5mg (starting dose)
• 4mg (next step up)
• 9mg (next step up)
• 25mg (maintenance dose)

Your prescriber will guide you through each stage based on how you're getting on. You can stay on a lower dose for as long as you need, especially if you’re losing weight steadily or dealing with side effects.

However, unlike injections, the aim is to reach the highest dose of 25mg, where you should see the most significant weight loss.

What dose do you start losing weight?

Many people notice appetite changes from their first dose of the Wegovy pill, with weight loss building gradually as doses increase.

The biggest results tend to come at the highest dose of 25mg. People who lost more than 10% of their weight by week 16 went on to lose an average of 22% by week 64. Everyone's different, though, so your prescriber will help find the right dose for you.

Administration

Both Mounjaro and Wegovy are given as a once-weekly subcutaneous injection. This means they're injected under the skin, not into a muscle or vein. The medication is self-injected using a pre-filled pen device. Each pen lasts for one month and contains 4 doses (except for Wegovy 7.2mg).

These injections can be taken at any time of day, with or without food, as long as the day remains consistent each week. Rotating between different injection sites reduces the risk of skin irritation.

Wegovy pills, meanwhile, are taken once a day, first thing in the morning, on an empty stomach with no more than 120ml of water. Each packet contains 30 pills, which is one month’s supply.

Mounjaro (injection)

Mounjaro is also supplied in a pre-filled pen designed for a once-weekly self-injection. Dose increases follow a structured, clinician-led schedule that can be amended depending on how well you tolerate each dose. Read more on how to inject Mounjaro with our expert guide.

Where do you inject Mounjaro?

Mounjaro is injected into the abdomen, thigh, or upper arm. The injection site should be rotated every week to reduce local skin reactions. Don’t inject into areas with redness, swelling, or irritation.

Wegovy (injection)

Once again, Wegovy is given in a pre-filled injection pen. Each pen contains 4 doses, which you’ll inject once a week. The only exception to this is Wegovy 7.2mg, which comes as 4 single-use pens that must be disposed of safely after each use.

The dose strength is increased gradually during the titration phase, after consulting your clinician or prescriber.

Where do you inject Wegovy?

Wegovy is injected into the abdomen, thigh, or upper arm. Injection sites should be rotated weekly to reduce skin irritation or lipohypertrophy. Avoid injecting into areas that are bruised, tender, or scarred.

Wegovy pills

Wegovy pills are taken daily, with each packet containing 30 tablets, which will last you for one month. Your dose will be increased slowly each month, with the goal of eventually reaching the maximum dose of 25mg.

You should:

• Take your Wegovy tablet first thing in the morning, before eating, drinking, or taking other oral medication.
• Swallow whole with up to 120ml of plain water only.
• Wait at least 30 minutes before eating, drinking, or taking other medications.
• Don't crush, chew or split the tablet.
• Take it at the same time each day.

If you miss a dose, skip it and take your next one as normal the next morning. Don't double up. If you miss several in a row, check in with your prescriber.

Mechanism of action

Mounjaro and Wegovy both act on gut hormone pathways that regulate appetite and blood sugar levels. They reduce hunger, increase feelings of fullness, and slow down the rate at which your stomach empties. However, Mounjaro targets 2 hormone receptors, while Wegovy only targets one.

GLP-1 receptor agonist (Wegovy injection and tablets)

Both Wegovy injections and tablets contain semaglutide, a GLP-1 receptor agonist. GLP-1 is a natural hormone that exists in your body to signal fullness, in addition to reducing appetite levels after eating. By mimicking this hormone, semaglutide increases feelings of fullness and helps you reduce your food intake.

GLP-1 also slows down your stomach emptying, meaning food stays in the stomach for longer. This helps you feel fuller for longer. GLP-1 has other benefits, like improving blood sugar regulation by supporting insulin production after meals.

GLP-1 and GIP receptor agonist (Mounjaro)

Mounjaro contains tirzepatide, which activates both GLP-1 and GIP receptors. This dual action targets two hormone pathways involved in appetite control and glucose metabolism.

GIP works alongside GLP-1 to influence insulin release and energy balance. By stimulating both receptors, tirzepatide can increase appetite suppression and influence metabolism (how well your body converts food into energy).

Effectiveness for weight loss

In clinical trials, both Mounjaro and Wegovy have been shown to produce significant weight loss when combined with lifestyle changes. However, average weight loss depends on dose, duration, and your individual response.

How much weight can you lose with Mounjaro?

In clinical studies, Mounjaro has shown impressive results. In the SURMOUNT-1 trial, which followed 2,539 people over 72 weeks, participants taking the highest dose of 15mg lost an average of 22.5% of their body weight.

More than half of the participants lost at least 20% of their body weight, and higher doses were generally associated with greater weight loss overall.

How much weight can you lose with Wegovy?

In clinical trials, people using Wegovy 2.4mg alongside lifestyle support lost an average of around 17% of their starting body weight over 68 weeks. As with any medication, results varied from person to person, with factors like dose tolerance playing a role in outcomes.

In another trial looking at the higher 7.2mg maintenance dose, the results were even more significant. On average, people lost 21% or more of their starting body weight over 72 weeks.

How much weight can you lose on Wegovy pills?

In the OASIS 4 trial, people on the highest 25mg dose lost around 17% of their starting weight on average over 64 weeks. Early responders, those who'd lost over 10% by week 16, went on to lose an average of 22%.

Which is more effective?

"While all three medications are effective for weight loss, clinical trials suggest Mounjaro may lead to greater average weight loss at higher doses.

“Wegovy pills offer results comparable to the Wegovy injection, with the added convenience of being a once-daily tablet rather than a weekly jab.

“That said, everyone responds differently, and the numbers from clinical trials don't tell the whole story. The most effective medication isn't simply the one with the strongest results in a trial. It's the one you can tolerate, stick with, and safely fit into your life. Long-term success comes down to what works for you."

Ayesha Bashir, weight loss expert at myBMI

Mounjaro vs. Wegovy cost

The cost of Wegovy and Mounjaro varies depending on the dose and provider. Prices typically increase as the dose strength increases.

Neither medication is usually available free for weight loss outside of specific NHS eligibility pathways.

Private pricing depends on whether the treatment is bought monthly or through structured bundles. Costs may also vary depending on availability and supply. It's important to compare like-for-like doses when reviewing price differences.

How much does Mounjaro cost?

Mounjaro starts from £169, but it varies by dose strength. Higher doses, like 10mg and above, are usually more expensive than lower doses.

How much does Wegovy cost?

Wegovy injections start from £119, but again, private Wegovy prices vary by dose strength. Lower doses are generally less expensive than the maintenance doses. Monthly pricing usually increases the higher the dose is.

How much do Wegovy tablets cost?

Wegovy tablets start from £99, with the price increasing as your dose does. Your prescriber will only recommend a higher dose if it's right for you.

Comparing side effects

Wegovy and Mounjaro have similar side effects because both act on gut hormone pathways. The most common side effects are gastrointestinal (affecting your stomach or digestive system), including:

• nausea
• diarrhoea
• constipation
• indigestion

Symptoms are usually mild to moderate and most often come on at the start of treatment or after a dose increase.

What are the Mounjaro side effects?

Commonly reported side effects of Mounjaro include:

• constipation
• diarrhoea
• indigestion
• nausea
• vomiting
• risk of low blood sugar (hypoglycaemia)

How severe are the side effects of Mounjaro?

Most side effects are mild to moderate and happen at the start of treatment or after dose increases. Severe reactions are uncommon but can occur and require prompt medical attention. Dose adjustment or a slower gradual increase may improve how well you tolerate Mounjaro.

What are the side effects of the Wegovy injection and tablets?

Commonly reported side effects of Wegovy include:

• nausea
• vomiting
• indigestion
• acid reflux or heartburn
• gastritis (inflamed stomach lining)

As they contain the same active ingredient, the side effects of both Wegovy products are similar.

How severe are the side effects of Wegovy?

Most people experience mild to moderate symptoms that improve over time. Serious reactions are rare, but they require an immediate medical assessment, for example, symptoms of pancreatitis or a severe allergic reaction.

Can I get help with side effects?

Yes. Side effects can be managed with diet changes, slower dose increases, or a temporary dose reduction. Always speak to your clinician if your symptoms are severe, persistent, worsening, or worrying you.

Side effects overview

Mounjaro and Wegovy have similar safety profiles. Both medications carry similar warnings, including risk of pancreatitis or of low blood sugar when used with other glucose-lowering medicines.

Gastrointestinal side effects like nausea, vomiting, diarrhoea, and constipation are common for both Mounjaro and Wegovy and usually come on during dose increases.

Availability

Wegovy and Mounjaro injections are available in the UK through NHS pathways and private prescription. Access depends on eligibility criteria, available supply, and clinical assessment. Not everyone will qualify for NHS treatment, and availability may vary by region.

At present, Wegovy pills are only available privately.

Where can I buy Mounjaro in the UK?

Mounjaro can be prescribed through NHS services for eligible patients and through regulated private clinics and pharmacies. You will need to have a clinical consultation before treatment can begin.

Where can I buy Wegovy in the UK?

Wegovy is also available via NHS eligibility pathways and regulated private providers. A clinical assessment and ongoing monitoring are necessary to get a prescription.

Where can I buy Wegovy pills in the UK?

At the moment, Wegovy tablets are only available privately in the UK.

Summary of Mounjaro vs. Wegovy

“Mounjaro, and both versions of Wegovy, can support meaningful, long-term weight loss. Whichever treatment you choose will depend on a range of factors, from price and effectiveness to whether you want a daily or weekly medication.

“If you start one treatment and find it isn't working as you hoped, you can speak to one of our clinicians about switching medication. And regardless of what you choose, we're here to support you every step of the way, with expert advice, personalised guidance, and our dedicated myBMI app.

“Remember everyone responds differently to the treatment; by working with your clinician we can support your weight loss journey safely.”

Ayesha Bashir, weight loss expert at myBMI

Sources

• Wegovy 1 mg, FlexTouch solution for injection in pre-filled pen. (2026) EMC [accessed 21 February 2026]
• Mounjaro KwikPen 7.5mg solution for injection in pre-filled pen. (2026) EMC [accessed 21 February 2026]
• Semaglutide vs Tirzepatide for Weight Loss in Adults With Overweight or Obesity. (2024) National Library of Medicine [accessed 21 February 2026]
• Obesity-Treatment. (2023) NHS [accessed 21 February 2026]
• Wegovy Pill Results. (2026). Wegovy. [accessed 9 July 2026].
• Early Responders to Oral Semaglutide 25mg: A Post Hoc Analysis of the OASIS 4 Trial. (2026). Novo Nordisk. [accessed 9 July 2026].