The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Going Back on Mounjaro After a Break
If you've taken a break from Mounjaro, you may be considering restarting treatment. Restarting tirzepatide after a pause requires careful planning with your prescriber, as your body's tolerance may have changed. This guide explains what to expect when going back on Mounjaro, how dose adjustment typically works, and important safety considerations for UK patients. Always consult your GP or prescriber before restarting any prescription medication.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
How Restarting Mounjaro Works in the UK
When restarting Mounjaro after a break, your prescriber will typically recommend beginning again from the starting dose of 2.5 mg, even if you previously reached a higher dose like 10 mg or 15 mg. This is because your body's tolerance to the tirzepatide may have reduced during your time off the medication. Restarting at 2.5 mg allows your system to readjust gradually and safely.
The dose titration (escalation) process will follow the standard schedule: staying on 2.5 mg for 4 weeks, then increasing to 5 mg, and continuing to escalate every 4 weeks if needed. Your prescriber may adjust this timeline based on your individual tolerance and response. If you experienced difficult side effects previously, your prescriber might recommend a slower escalation or a lower maximum dose than before.
The length of your break affects how your body responds. A short break of a few weeks typically means faster readjustment, whereas a break of several months may require more careful reintroduction. Your prescriber will take your break duration and previous experience into account.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Side Effects When Restarting and What to Expect
You may experience side effects again when restarting Mounjaro, even if you didn't have them previously. Common side effects like nausea, constipation, and stomach discomfort are most likely in the first 2–4 weeks. These often settle as your body readjusts, similar to when you first started. Taking Mounjaro with food and staying hydrated can help manage early side effects.
Some patients find side effects less severe on restart because they know what to expect, whilst others experience them differently than before. This variation is normal and individual. If side effects are severe or persistent, contact your GP or prescriber—they may slow your dose escalation or recommend additional support. Keep track of how you feel using our free progress tracker to help you communicate changes to your prescriber.
---COL_J_END---- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Can I restart Mounjaro at the same dose I stopped at?
No. Your prescriber will typically recommend starting again at 2.5 mg, the initial dose, even if you previously reached 10 mg or 15 mg. Your body's tolerance may have decreased during your break, so restarting at 2.5 mg is safer. You'll then retitrate (escalate) gradually over subsequent weeks.
Why would I need a break from Mounjaro?
Breaks may be recommended for several reasons: pregnancy planning (tirzepatide is not suitable during pregnancy), managing persistent side effects, financial reasons, or if your GP feels a pause is medically appropriate. Always discuss breaks with your prescriber rather than stopping suddenly.
How long can I safely be off Mounjaro?
There's no fixed time limit. Your prescriber can advise based on your situation. Breaks from a few weeks to several months are generally manageable, though longer breaks may mean your body needs more time to readjust when restarting.
Will restarting Mounjaro be as effective as before?
Many patients see similar weight loss results when restarting, especially if combined with continued diet and exercise habits. However, individual response varies. Your prescriber can help set realistic expectations based on your personal history with the medication.
Is tirzepatide (Mounjaro) available on the NHS when restarting?
NHS access to tirzepatide is through specialist tier 3 weight management services following NICE approval, though availability varies by region. Private prescription through UK online services is also available. Discuss your options with your GP or weight management service.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.