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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Mounjaro Withdrawal Symptoms vs Wegovy — What's the Difference?
Stopping Mounjaro or Wegovy can cause rebound effects, but withdrawal between the two medications differs due to their different mechanisms. Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy is GLP-1 only. Both are prescription-only weight management injections used in the UK, and both require clinical assessment before starting. Understanding what happens when you stop either medication can help you plan your weight management strategy with your prescriber.
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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 Mounjaro and Wegovy Stopping Effects Differ
Mounjaro (tirzepatide) activates two hormone pathways—GIP and GLP-1—making it a dual-action medication. When stopped, some people experience a faster return of appetite and food cravings because both pathways stop being stimulated simultaneously. Wegovy (semaglutide) activates only the GLP-1 pathway, so its withdrawal effects relate to GLP-1 signalling alone.
Common rebound effects when stopping either medication include:
- Increased appetite and food cravings
- Weight regain (typically gradual over weeks to months)
- Return of nausea or stomach changes as appetite normalises
- Changes in blood sugar control (if diabetic)
- Mood or energy shifts as gut hormone signalling re-establishes
Individual responses vary significantly. Some people experience minimal rebound; others notice appetite return within days. Your prescriber can advise on a safe stopping plan tailored to your situation.
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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
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Which Medication Has Stronger Withdrawal Effects?
There is no definitive clinical evidence that one medication causes stronger withdrawal than the other—this is an individual experience. Mounjaro's dual mechanism may theoretically cause more noticeable appetite changes because it affects two pathways, but clinical trial data doesn't directly compare withdrawal profiles. Both medications are designed for ongoing use, not short-term courses, so stopping is not typical use. If you're considering stopping either medication, discuss this with your prescriber first. They can help you understand what to expect based on how long you've been on treatment, your starting weight, and your individual health profile. Use our free GLP-1 weight loss calculator to track your progress during treatment, and consider our progress tracker to log any changes if you do stop either medication.
- 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.
What is withdrawal from Mounjaro or Wegovy?
"Withdrawal" is not a clinical term for these medications—they don't cause physical dependence. What people experience is rebound: appetite returns, and weight may regain when the medication is stopped. This happens because the hormone-mimicking effects cease.
How quickly does appetite return after stopping Mounjaro?
Appetite typically returns within days to a few weeks after the last injection. Because Mounjaro leaves your system over approximately 4–5 weeks, some appetite suppression may continue for that period, then increase more noticeably.
Is Wegovy easier to stop than Mounjaro?
There's no clinical evidence one is "easier" to stop than the other. Both cause appetite rebound when stopped. Individual experience varies. Your prescriber can advise on a gradual dose reduction plan if you're concerned about stopping.
Will I regain all my weight if I stop Mounjaro or Wegovy?
Not necessarily. Weight regain depends on whether you maintain the lifestyle changes—diet and activity—that supported your weight loss. Many people keep some weight off if they continue healthy habits, though some gradual regain is common.
Can I switch from Mounjaro to Wegovy to avoid withdrawal symptoms?
Switching between medications doesn't avoid rebound appetite—it changes which hormone pathway is active. Both require a prescriber's guidance. Your GP or weight management prescriber can advise on whether switching suits your individual 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.