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
Free tracker included with every download this week
Coming Off Mounjaro: Side Effects, Cost & UK Access
Stopping Mounjaro can cause side effects including rapid weight regain, increased appetite, and nausea as your body adjusts. Understanding what to expect when discontinuing tirzepatide, plus knowing your options for accessing Mounjaro in the UK through NHS or private routes, helps you make informed decisions about your weight management. This guide covers withdrawal effects, cost context, and the prescription process for UK adults.
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Calculate Your BMI Instantly
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: Rebound Effects & Cost Context
When you stop taking Mounjaro (tirzepatide), your body may experience rebound weight gain within weeks as appetite hormones normalise. Common side effects of discontinuation include increased hunger, cravings returning, nausea, and fatigue as your system readjusts. Clinical data suggests many people regain 50% or more of lost weight within 12 months of stopping, though individual responses vary significantly.
The UK's dual access route means Mounjaro availability differs by location. NHS access through specialist tier 3 weight management services involves referral from your GP, but waiting lists in many regions extend 6–18 months. Private prescriptions via online clinical assessments are available immediately through GPhC-registered pharmacies, with doses typically costing £180–£320 monthly depending on strength—the Mounjaro KwikPen comes pre-filled with four weekly injections. Both routes require initial clinical assessment to confirm eligibility: BMI ≥30 or BMI ≥27 with weight-related health conditions.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
NHS vs Private Access: How to Get Mounjaro in the UK
NHS Route: Request a referral from your GP to a tier 3 weight management service. NICE has approved tirzepatide for NHS use, but regional availability is patchy. You'll be assessed for eligibility and dose-escalated over 16–20 weeks. No direct cost, but delays are common.
Private Route: Complete an online consultation with a UK-licensed prescriber (takes 15–30 minutes). If approved, your prescription is dispensed by a GPhC-registered pharmacy within 1–2 days. You manage your own dose progression, supported by guidance. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses before committing.
Whichever route you choose, discuss discontinuation plans with your prescriber to manage rebound effects through dietary and lifestyle strategies.
- 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 side effects occur when stopping Mounjaro?
Common rebound effects include increased appetite, weight regain, nausea, fatigue, and mood changes. These typically develop within 2–4 weeks of stopping as your body's hunger hormones normalise. Severity varies—some people experience minimal symptoms while others find the transition challenging. Your GP can advise on managing these effects through dietary support.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs £180–£320 monthly depending on dose and provider. Each KwikPen contains four weekly injections (one month's supply). Starting dose (2.5mg) is typically cheaper than maintenance doses (10–15mg). Prices vary between pharmacies—compare options before prescribing. NHS provision is free but involves waiting.
Can I access Mounjaro through the NHS in the UK?
Yes—NICE has approved tirzepatide for NHS specialist weight management services (tier 3). You need a GP referral, and eligibility requires BMI ≥30 or ≥27 with comorbidities. However, NHS provision is very limited regionally and waiting lists often exceed 12 months. Availability varies significantly by integrated care board.
How long does the online consultation take for private Mounjaro?
Online consultations typically last 15–30 minutes. You answer health questions, discuss your weight loss goals, and current medications. A UK-licensed prescriber reviews your answers and decides whether Mounjaro is clinically appropriate for you. If approved, your prescription is sent to a pharmacy the same day.
Will I regain weight quickly if I stop Mounjaro?
Weight regain after stopping is common—clinical data shows many people regain 50% of lost weight within 12 months, though some maintain better. Rebound happens because appetite hormones return to baseline. Combining dietary consistency, physical activity, and behavioural strategies can slow regain. Discuss longer-term weight management plans with your prescriber before discontinuing.
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.