Wegovy and Mounjaro are very similar treatments. They’re both once-weekly injections that help you lose weight and maintain your results. However, there are some differences between them, such as price, active ingredient, and available doses.

Here, we’ll give you everything you need to know about Wegovy and Mounjaro so you can understand each treatment and decide which is most suitable for your weight loss journey.

How do Wegovy and Mounjaro work for weight loss?

Wegovy and Mounjaro injections support weight loss by reducing appetite and helping you feel fuller for longer. This makes it easier to stick to a calorie deficit and a healthy diet. When combined with healthy eating and regular exercise, this can lead to faster and more sustainable weight loss.

They belong to a group of medications called GLP-1s (glucagon-like peptide-1 receptor agonists) and work by mimicking a naturally occurring hormone in your body. By copying this hormone, these treatments:

• Send signals to your brain that you’re full, as if you’ve just eaten, helping to reduce your appetite

• Delay how quickly your stomach empties, so you feel fuller for longer

What’s the difference between Mounjaro and Wegovy?

There are only slight differences between Mounjaro and Wegovy, as they contain similar ingredients and work in a very similar way to help you lose weight. Both treatments are approved and licensed for use in the UK, but Wegovy has been available for longer. The main differences between them are their active ingredient, effectiveness, and price.

Active ingredients

Wegovy contains the active ingredient semaglutide, a GLP-1 receptor agonist. Mounjaro contains tirzepatide, a dual GIP/GLP-1 receptor agonist. Both medicines can help you lose weight when used alongside a healthy diet and exercise plan. Here’s how they work:

GLP-1 is a hormone your body releases after eating to tell your brain you’re full. It slows how quickly your stomach empties and helps lower blood sugar by improving how your body produces insulin. Semaglutide and tirzepatide mimic this hormone, helping you feel satisfied with less food. This can make it easier to reduce your calorie intake without feeling too hungry between meals.

Mounjaro also acts on the GIP pathway (glucose-dependent insulinotropic polypeptide), which works a little differently from GLP-1. Activating GIP helps your body release insulin after eating and may improve how your body processes fat, so you store less over time. Together, GIP and GLP-1 activity can support greater weight loss for most people.

Effectiveness

While Mounjaro is considered slightly more effective, both treatments have been proven to help people safely and successfully reach their weight loss goals.

In clinical trials, Wegovy has been shown to help people lose around 15-17% of their body weight after about 68 weeks, while Mounjaro has been shown to help people lose up to around 22% after 72 weeks. This means both treatments are effective for weight loss, but Mounjaro may lead to slightly greater results for some people. However, as these tests were not carried out as a direct comparison, it’s hard to confirm which is more effective.

Mounjaro vs Wegovy doses: 

• Wegovy is available in doses of 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg.

• Mounjaro is available in doses of 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg.

With both treatments, you can increase your dose every four weeks. However, you can choose to stay on the same dose for longer if it is working well for you and you are comfortable.

Dosing scheduling

Wegovy and Mounjaro both come in different doses but are administered in the same way: once a week. With both medicines, you start at the lowest dose and gradually increase until you reach your maintenance dose. This allows your body to adjust safely while helping to minimise side effects.

Wegovy vs Mounjaro cost:

Manufacturers: Who makes Wegovy and Mounjaro?

Wegovy is manufactured by Novo Nordisk, a Danish company. Mounjaro is manufactured by Eli Lilly, a North American company. Novo Nordisk also manufactures Ozempic, Rybelsus (an oral medication for diabetes), and Saxenda – one of the first weight loss medications available in the UK.

What are the main similarities between Wegovy and Mounjaro?

Mounjaro and Wegovy share a lot of similarities, from how they’re administered to some of their side effects. Here, we take a deeper look.

How they’re administered

Wegovy and Mounjaro come as multi-dose injectable pens, which you can use yourself from the comfort of your home. Each pen lasts for four weeks. All pens are pre-filled, so you don’t need to worry about drawing up your own medication, and they’re administered in exactly the same way.

How to take Wegovy and Mounjaro         

Each treatment is taken in the exact same way. You inject it once a week, on the same day and time, with or without food. Sticking to a regular dosing schedule helps to keep Wegovy and Mounjaro effective and ensures your appetite stays suppressed. Here’s how our full guide on how to inject your treatment. 

Mounjaro vs Wegovy side effects: 

Wegovy has very similar side effects to Mounjaro, as both treatments mimic the same hormone. The only main difference between the side effects is how common they are, depending on the treatment. Some happen more with Wegovy, others with Mounjaro.

Here’s a breakdown of how this looks:

Most side effects from Wegovy and Mounjaro tend to be mild and go away on their own as your body adjusts to the treatment. If you’re struggling to manage side effects or think you may be experiencing serious ones, it’s important to speak to your prescriber or seek urgent medical help.

Titration

When you take Wegovy or Mounjaro, your dose is gradually increased every four weeks as your body gets used to the medication. This process is called titration. Both medications follow the same approach to titration until you reach your maintenance dose.

Your maintenance dose is the final dose you stay on, as it’s the most effective for supporting your weight loss.

Wegovy titration schedule: 0.25 mg → 0.5 mg → 1 mg → 1.7 mg → 2.4 mg

Mounjaro titration schedule: 2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg

Both treatments are prescription-only

To get either Mounjaro or Wegovy, you must have a prescription from a doctor or prescribing pharmacist. This is because your prescriber needs to make sure the treatment is safe and suitable for you. There is also strict prescribing criteria you must meet before starting either medicine.

You may be eligible for Wegovy or Mounjaro if you:

• Have a body mass index (BMI) of 30 or higher, or a BMI of 27–30 with a weight-related medical condition or risk factor, such as prediabetes
• Are not taking any medications, or have any medical conditions, that would make it unsafe to use either treatment
• Do not have an allergy to any of the ingredients in either medicine

Can you switch from Mounjaro to Wegovy or Wegovy to Mounjaro?

Yes – you can switch between treatments, provided your prescribing pharmacist or doctor thinks it’s safe and suitable for you. You’ll need to stop taking your current treatment and wait for it to fully leave your system before starting the new one.

Learn more about switching to Wegovy.

Why would I want to switch treatment?

• You’re not getting the results you want. If you’re not seeing the progress you hoped for, a different treatment may work better for you
• You’re experiencing side effects. Everyone reacts differently, and if one treatment is causing difficult or unmanageable side effects, your prescriber may recommend switching
• You want to make a change. You might have read about a new treatment, or prefer the pricing or effectiveness of another option. These are all valid reasons to switch, provided your prescriber thinks it’s safe and suitable for you

Can you take Wegovy and Mounjaro at the same time?

No, you should not take Mounjaro and Wegovy together. This applies to any prescription weight loss medication. Taking more than one at the same time can increase your risk of serious side effects and severe illness.

This is also why you need to leave a gap when switching treatments, to make sure the first medicine has completely left your system before starting the next. Taking multiple weight loss treatments can also cause you to lose too much weight too quickly, which can seriously impact your health.

Which one is best for me?

Both Wegovy and Mounjaro have been proven to be safe and effective, and there is no ‘best’ treatment. Instead, it’s about finding the one that works best for you. Finding the right one for you comes down to a few factors:

Suitability

When you request treatment, we review your medical history to make sure it’s safe and suitable for you. One treatment may be a better option for you, and we’ll make sure you’ve got the safest, most effective option based on your health.

Price

Your budget can also affect your decision. While both treatments are similar prices, Wegovy is slightly cheaper, which may make it more suitable for you.

Side effects

Both medications have similar side effects, but some are more common depending on the treatment you’re using. People also react differently to certain treatments, so you might find you tolerate one treatment better than the other.

Your current medication

Mounjaro can reduce the effectiveness of oral contraception due to its dual-action mechanism in the body, meaning you'll need alternative contraception like condoms while taking it. Wegovy doesn't affect contraception, making it a safer choice if you rely on the pill.

This is important to consider when choosing between treatments, as pregnancy isn't safe during use. Always discuss your contraception needs with your prescriber to ensure you're fully protected.

Learn more about weight loss injections and oral contraception.

Availability

Due to demand, weight loss treatments can experience availability issues. While this doesn’t happen often, it’s worth considering availability to ensure a smooth weight loss journey. We currently do not have supply issues with our weight loss treatments readily available. 

Your preference

At the end of the day, it comes down to what treatment you think is going to best match your needs. It will still need to be approved by our clinical team, but they do consider your preference throughout.

If you aren’t sure, our pharmacists can help you make a decision.

Alternative weight loss treatments to Mounjaro and Wegovy

Wegovy and Mounjaro aren’t the only options when it comes to weight loss treatments. We can also provide weight loss tablets if these are more suitable for you.

Frequently asked questions: Mounjaro Vs Wegovy

Is Wegovy or Mounjaro more expensive?

Wegovy tends to be more affordable than Mounjaro. At Chemist4U, we provide Wegovy from £99, and Mounjaro starts from £139.

Will Wegovy or Mounjaro be more effective?

Both Wegovy and Mounjaro have shown impressive results in clinical trials:

Wegovy: Around half of people taking it lost 17% or more of their starting weight after 68 weeks on the 2.4mg maintenance dose.

Mounjaro: On the highest maintenance dose of 15mg, people lost up to 22.5% of their starting weight after 72 weeks.

As the studies ran for different lengths of time and weren’t designed to compare the two medicines directly, it’s not possible to say for sure which is more effective.

How long do I need to stay on either Mounjaro or Wegovy to lose weight?

You can stay on either Mounjaro or Wegovy for as long as it takes to reach your goal weight. You can also continue to stay on each treatment to help you maintain the weight you’ve lost. We call this maintenance and weight management.

Most patients find they lose around 22.5% of their weight on Mounjaro over a 72-week period and around 15-17% of their weight on Wegovy over the same period.

Can I get Wegovy or Mounjaro on the NHS?

Yes – but access is limited. Currently, Mounjaro and Wegovy are usually only prescribed through a tier 3 specialist weight management service. Your GP can refer you if you meet the eligibility criteria, but waiting times can be long and vary depending on where you live.

Some GPs are now being trained to prescribe weight loss injections directly, but this isn’t widely available just yet.

Get healthcare support when you need it

Whatever weight loss medication you would prefer, our dedicated team is here to support you every step of the way. If you need guidance, call us on 01695 474 433 or submit your request directly here.

"We're committed to making your healthcare journey as simple, safe and convenient as possible," explains Jason. "When you order from us, you'll benefit from expert clinical support, convenient reorder reminders, and carefully curated resources to help you maintain momentum toward your weight loss goals."