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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Stopping and Restarting Mounjaro for Weight Loss
If you're taking Mounjaro (tirzepatide) for weight management, you may wonder about stopping and restarting treatment. This is a common question among UK adults using this weekly weight loss injection. Understanding how to safely pause or resume Mounjaro, and what happens to your weight during a break, is important for making informed decisions about your health. Your prescriber can guide you through the process, but here's what you need to know about managing your treatment responsibly.
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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.
What Happens When You Stop Mounjaro
When you stop taking Mounjaro, your body gradually returns to its normal appetite and hunger hormone patterns. Most people notice changes within days to weeks—appetite typically increases, and the feeling of fullness after meals reduces. Weight regain is common: clinical evidence suggests many people regain 50% or more of lost weight within months of stopping, though individual responses vary significantly.
- Appetite returns quickly — often within 2–3 weeks as GIP and GLP-1 signalling normalises
- Metabolic rate adjustment — your body may need time to readjust to normal eating patterns
- Weight regain risk — without continued dietary and exercise changes, weight often returns
- No withdrawal symptoms — stopping Mounjaro does not cause physical withdrawal, though hunger can feel sudden
The key is maintaining the healthy eating and exercise habits you developed while on treatment. Stopping the prescription weight loss injection does not erase the lifestyle changes you've made—those continue to protect you.
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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.
Restarting Mounjaro After a Break
If you've stopped Mounjaro and want to restart, you must contact your prescriber first—do not restart without clinical guidance. When restarting, you typically begin again at the starting dose (2.5 mg), not where you left off, even if you were on a higher maintenance dose like 10 mg or 15 mg. Your prescriber will reassess your health, discuss your weight changes during the break, and plan your dose titration schedule carefully.
- Restarting requires a new clinical assessment and prescription
- Begin at 2.5 mg and escalate by 2.5 mg every 4 weeks (standard titration)
- Your prescriber may adjust timing based on your individual response
- Use our GLP-1 weight loss calculator to project outcomes with different doses
- 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.
Why would someone stop taking Mounjaro?
Common reasons include side effects (nausea, stomach pain), cost concerns, life changes, or planned pregnancy. Some people pause temporarily during illness. Always discuss stopping with your prescriber rather than stopping abruptly, as they can help manage side effects or explore alternatives.
Can I skip one week of Mounjaro and then restart?
Missing one or two doses differs from intentionally stopping. If you've missed a dose within 4 days, take it as soon as remembered. For longer gaps, contact your prescriber. Restarting after a planned multi-week break requires a new assessment and prescription from your healthcare provider.
Will I lose the same amount of weight if I restart Mounjaro?
Individual results vary when restarting. You may lose weight at a similar rate as before, but your body's response may differ. Weight loss depends on your dose, adherence, diet, exercise, and individual metabolism. Your prescriber will monitor your progress during the titration phase.
How long should I wait before restarting after stopping Mounjaro?
There is no set waiting period—timing depends on your individual health and reasons for stopping. If you stopped due to side effects, your prescriber may recommend waiting or trying a different medication. Discuss your timeline with your healthcare provider before restarting any weekly weight loss injection.
What if I regain weight after stopping Mounjaro?
Weight regain after stopping is common and does not mean treatment failed. Calculate your current BMI using our free BMI calculator to understand your health status. Speak to your GP about long-term options: restarting Mounjaro, trying an alternative GLP-1 medication like Wegovy, or other weight management strategies suited to your circumstances.
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.