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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Restarting Mounjaro After Taking A Month Break
If you've paused your Mounjaro treatment for a month, restarting the medication requires careful planning and GP or prescriber guidance. This guide covers NHS and UK-specific considerations for resuming tirzepatide injections safely. Restarting after a break is different from continuing regular doses — your prescriber may adjust your approach based on how long you've been off the medication and your individual health context. Always consult your GP or licensed prescriber before restarting any prescription weight loss medication.
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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.
Why You Might Have Paused Mounjaro and What Happens When You Restart
Common reasons for pausing Mounjaro include managing side effects, financial reasons, or planned treatment breaks. After a one-month pause, your body's tolerance to tirzepatide may have partially reset, meaning side effects like nausea might return when you restart, even if you were on a higher maintenance dose. Your GP or prescriber will assess whether to restart at your previous dose, step back down to a lower dose, or restart the full titration schedule. This depends on your individual circumstances, how long you've been off the medication, and your current health status. The NHS tier 3 specialist weight management services and private prescribers both follow similar principles: personalised assessment before resuming treatment. Do not restart Mounjaro without clinical guidance — a prescriber needs to confirm this is still appropriate for you and determine the safest restart approach.
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.
Practical Steps for Restarting — NHS and Private Routes
If you're on an NHS specialist service: Contact your tier 3 weight management clinic directly before restarting. They hold your clinical records and will advise based on your specific journey with the medication. If you're accessing Mounjaro privately: Arrange a follow-up consultation with the prescriber or online clinic. Most GPhC-registered providers will require a brief reassessment before issuing a new prescription, especially after a one-month break.
- Notify your prescriber of any health changes during the break
- Confirm your current weight and any side effects you experienced previously
- Clarify the restart dose and timeline with your prescriber in writing
- Store your Mounjaro KwikPen correctly — if you have an old pen from before the break, check the expiry date before attempting to use it
Use our free GLP-1 weight loss calculator above to understand projected outcomes based on different Mounjaro doses, which can help you discuss realistic expectations with your prescriber when restarting. If you're tracking your weight loss journey, our progress tracker allows you to log your weight before and after the restart, giving you clear visibility of results once you resume treatment.
- 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.
Do I restart at my previous dose after one month off Mounjaro?
Not necessarily. Your prescriber will decide based on your individual circumstances. Some people restart at their previous dose if side effects have settled; others step back down or restart the full titration schedule. Contact your GP or prescriber before restarting — do not assume you can resume where you left off without clinical guidance.
Will side effects return when I restart Mounjaro after a month?
Possibly. After a one-month break, your body's tolerance may have partially reset, meaning nausea, diarrhoea, or constipation can recur — even at your previous dose. Starting slowly or at a lower dose can help manage this. Your prescriber will discuss what to expect based on your history with the medication.
How do I get a prescription to restart Mounjaro on the NHS?
Contact your tier 3 weight management service directly. They manage NHS-prescribed Mounjaro and will assess whether restarting is appropriate, adjust your dose, and issue a new prescription. Waiting times vary by region, so contact them as soon as you're ready to restart.
Can I buy Mounjaro privately after a month break without NHS referral?
Yes. Private online prescribers in the UK can assess and prescribe Mounjaro without NHS referral. You'll need a brief consultation confirming your health status and weight, then a GPhC-registered pharmacy can dispense your prescription. This route is faster than NHS but involves a cost per dose.
What if I lost my previous Mounjaro KwikPen — can I use it if it's still within expiry?
Do not use an old pen without checking it with your prescriber first. Verify the expiry date, storage conditions, and that it hasn't been frozen or overheated. Your prescriber may advise disposing of it and starting with a fresh pen instead, especially after a one-month break.
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.