Mounjaro® Dosage: What You Need to Know in the U.K.
Key takeaways:
The starting dose of Mounjaro® is 2.5 mg weekly.
You typically increase your dose every four weeks, depending on how you tolerate the side effects.
The Mounjaro® maintenance dose is between 5 and 15 mg weekly.
Your healthcare provider will personalise your treatment plan and follow up regularly.
Mounjaro® (tirzepatide) is a once-weekly injection licensed in the United Kingdom for people living with obesity or overweight. Like other weight loss injections, it works by mimicking hormones in the body that help regulate appetite, blood sugar levels, and digestion.
Your Mounjaro® dosage depends on your health needs, your body’s response to the medicine, and guidance from your healthcare provider. Here’s what you should know about the dosing schedule, how it works, and what to expect.
How Mounjaro® Works
Mounjaro® is a weight loss injection containing tirzepatide. Originally licensed for type 2 diabetes, the Medicines and Healthcare products Regulatory Agency (MHRA) has authorised it as a weight loss treatment.
Tirzepatide activates two receptors:
Glucagon-like peptide-1 (GLP-1)
Glucose-dependent insulinotropic polypeptide (GIP)
For this reason, it’s called a dual GLP-1/GIP agonist.
GLP-1 and GIP are naturally occurring hormones. They help support weight loss by:
Stimulating insulin release
Reducing appetite
Slowing down digestion
Regulating blood sugar levels
Research has shown that Mounjaro® is a highly effective weight loss treatment — for people with and without type 2 diabetes.
In the U.S., tirzepatide is also available under the brand name Zepbound®. In the U.K., it’s only available as Mounjaro®, as the MHRA has not yet authorised Zepbound®.
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What Is the Recommended Mounjaro® Dosage?
The recommended Mounjaro® dose is between 2.5 and 15 mg (milligrams) weekly. Generally, you start with a low dose and increase it over time, escalating your dose every four weeks. This gradual dose escalation schedule reduces the risk and severity of side effects.
Your prescribing clinician will help you figure out the right Mounjaro® dose. They might:
Increase your dose over time
Increase your dose further if you’re not seeing weight loss results
Decrease your dose if you’re experiencing intolerable side effects
Once you’ve reached your weight loss goals, your provider will probably move you to a maintenance dose.
Mounjaro® Dosage Chart for Weight Loss
Here’s an example of a Mounjaro® dose escalation schedule. Your personal dosage schedule will depend on your medical provider’s prescription.
Week | Dosage | Notes |
Weeks 1–4 | 2.5 mg weekly | Starting dose (not for glycaemic control) helps the body adjust |
Weeks 5+ | 5 mg weekly | First maintenance dose and minimum effective dose |
After 4 weeks | Increase in 2.5 mg steps (7.5 mg, 10 mg, 12.5 mg) | Only if tolerated and needed |
Maximum dose | 15 mg weekly | Highest maintenance dose |
Why Do You Have to Increase Mounjaro® Dose?
Increasing your Mounjaro® dose helps promote more weight loss. If you’re already losing a lot of weight on a low dose, your healthcare professional might wait a bit longer to increase your dose.
You usually have to increase your dose slowly over time to lower the risk of side effects. This helps your body get accustomed to tirzepatide so the treatment feels more tolerable.
If you have concerns about your Mounjaro® dose, speak with your prescribing clinician.
Do You Lose More Weight on Higher Dose of Mounjaro®?
Generally, yes.
In a clinical trial, over 2,500 participants were given tirzepatide or a placebo weekly for 72 weeks. The research found that their weight loss was dose-dependent:
Those who took 15 mg of tirzepatide weekly lost about 21 percent of their initial body weight.
Those who took 10 mg of tirzepatide weekly lost around 19.5 percent.
Those who took 5 mg of tirzepatide weekly lost roughly 15 percent.
Those on the placebo lost about 3.1 percent.
A 2025 review of trials also concluded that higher doses of tirzepatide lead to more weight loss. But higher doses are also associated with a higher risk of side effects (or more severe side effects).
The best dose for you will depend on tolerability and guidance from a healthcare professional. Sometimes, a lower dose works well for a longer period. Gradual, sustainable weight loss can be better in the long term.
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What Happens if You Miss a Dose of Mounjaro®?
You’re supposed to take Mounjaro® on the same day each week, at any time of the day. What happens if you miss your weekly dose of tirzepatide?
Here’s the general rule of thumb:
If it’s within four days (96 hours) of your scheduled dose, take the missed dose as soon as possible.
If more than four days have passed since the missed dose, skip it and take your next dose at the regular time.
Never inject two doses within three days (72 hours) of each other. This can result in side effects.
If you’re ever unsure, check your patient information leaflet or speak with your healthcare provider.
Tip: Use a calendar or set an alarm reminding you to take your medication. That way, you’re less likely to forget a dose.
Alternatives to Mounjaro® in the U.K.
If you can’t use Mounjaro®, there are a number of alternative weight loss treatments in the U.K.
These include:
Wegovy® (semaglutide), a weekly GLP‑1 injection
Saxenda® (liraglutide), a daily GLP‑1 injection
Orlistat, an oral weight loss medication that reduces fat absorption from food
While these medications can be helpful for weight management, they’re not a silver bullet. All weight loss drugs work best when combined with a balanced, reduced-calorie diet, regular exercise, and healthy lifestyle habits.
If you’re considering Mounjaro® or an alternative, your GP (general practitioner) or a private care provider can help you weigh up your options.
The Gist of Mounjaro® Dosage
Mounjaro®, a weekly weight loss injection containing tirzepatide, can be highly effective for supporting weight loss. Here’s the long and short of Mounjaro® dosing:
The Mounjaro® starting dose is 2.5 mg. You’ll gradually increase the dose to improve your tolerance of the side effects.
The maximum Mounjaro® dose is 15 mg. Not everybody will need 15 mg, though. You might have good results and lose enough weight on a lower dose.
The right maintenance dose varies. It can range from 5 mg to 15 mg weekly.
Ready to get started on your weight loss journey? We can help you connect with a U.K.-licensed healthcare professional to discuss whether Mounjaro® is suitable for you.
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FAQs
Get answers to commonly asked questions about Mounjaro® U.K. dosages.
What is the starting dose of Mounjaro® for weight loss?
The starting dose of Mounjaro® for weight loss is 2.5 mg once a week. After the first four weeks, you’ll typically increase your dosage. This gives your body time to adjust to the medication and helps minimise side effects.
When to increase Mounjaro® dose for weight loss?
Your healthcare provider may increase your dose every four weeks. Your exact dosage schedule will depend on how well you tolerate side effects and whether more weight loss support is needed.
What is the maximum maintenance dose of Mounjaro®?
The maximum recommended maintenance dose of Mounjaro® is 15 mg weekly, though not everyone will need this dose. If you find the side effects hard to tolerate, or if you’re losing enough weight on a lower dose, you might not need to escalate to 15 mg.
Do you lose more weight on a higher dose of Mounjaro®?
Higher doses have been linked to greater weight loss, but also worse side effects (like constipation and nausea). The right dose varies by person. Starting with a low dose and gradually increasing it is the best way to find what works best for you.
What if I miss a Mounjaro® injection?
If it’s within four days of your missed dose, take the missed dose right away. If more than four days have passed, skip it and take your next scheduled dose as planned.
Where do I inject Mounjaro®?
Mounjaro® is injected just under the skin (not into a muscle). Common injection sites include the stomach, thigh, and upper arm. To lower the risk of irritation, rotate injection sites each week. Your provider will show you how to use the pre-filled pen safely before you start.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your GP about the risks and benefits of any treatment.