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
What to Do If You Hit a Plateau on Mounjaro
A weight loss plateau on Mounjaro is common and doesn't mean the medication has stopped working. Many people experience periods where weight loss slows down temporarily, even though the tirzepatide dose is still active. Understanding why this happens, how to access Mounjaro in the UK, and what your options are can help you stay motivated and make informed decisions about your treatment.
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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.
Accessing Mounjaro in the UK: Cost and Route Options
In the UK, Mounjaro is available through two main routes: NHS specialist services and private online prescribing. NHS access is through tier 3 or 4 specialist weight management services — you'll need a GP referral, and availability varies significantly by region. NHS waiting lists can be several months or longer depending on your area.
Private prescribing is faster: you'll have an online consultation with a UK-licensed prescriber, who assesses your eligibility. If approved, your prescription is dispensed by a GPhC-registered pharmacy. Private Mounjaro typically costs £150–£300 per month depending on your dose. The 2.5 mg starting dose is usually at the lower end; the 15 mg maximum dose at the higher end. Each KwikPen contains four weekly injections (one month supply). Pricing can vary between providers, so it's worth comparing options if you're considering private access.
Both routes require a clinical assessment — your prescriber will check your BMI, health conditions, medications, and whether Mounjaro is appropriate for you. Individual eligibility varies.
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: What's Right for You?
NHS route pros: Free treatment (after initial referral). Ongoing GP oversight. Suitable if you can wait and prefer NHS care.
Private route pros: Faster access. No waiting list. Flexibility with timing and dose adjustments. Suitable if you need treatment sooner and can fund it privately.
If you're experiencing a plateau, discuss it with your prescriber—whether NHS or private. They may suggest dose titration (moving to the next dose level), reviewing your diet and activity, or other strategies. Use our GLP-1 weight loss calculator to explore potential outcomes at different dose levels, and track your progress with our free progress tracker to spot patterns in your weight.
- 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 do weight loss plateaus happen on Mounjaro?
Plateaus occur as your body adapts to the medication and calorie deficit. Your metabolic rate may adjust, and hunger hormones can normalise over time. This is temporary and normal. Your prescriber may recommend a dose increase, or lifestyle adjustments like adjusting your calorie intake or activity levels. Continue the medication as prescribed—stopping abruptly is not advisable.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs approximately £150–£300 per month, depending on your dose. Starting doses (2.5–5 mg) are usually cheaper; higher maintenance doses (10–15 mg) cost more. Each KwikPen contains four weekly injections. Costs vary between providers, so compare before committing. NHS access is free but involves longer waiting times.
Can I switch from Mounjaro to Wegovy if I hit a plateau?
Switching medications should only be done under prescriber guidance. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist, while Wegovy (semaglutide) is a single GLP-1 agonist. Some people respond better to one over the other, but switching requires a clinical assessment and prescription. Discuss this with your prescriber.
What happens if I can't afford private Mounjaro?
If private costs are unaffordable, ask your GP about NHS referral to a specialist weight management service. NHS waiting lists are long in many areas, but access is free once approved. Alternatively, discuss with your prescriber about pausing treatment temporarily if cost becomes a barrier — never stop without guidance.
How do I know if my plateau is temporary?
Track your weight weekly using our free progress tracker—you'll spot patterns over 2–4 weeks. Plateaus typically last 2–8 weeks. Use our GLP-1 weight loss calculator to confirm you're still in a calorie deficit. If your plateau lasts longer than 8 weeks with no movement, discuss with your prescriber about dose titration or lifestyle review.
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.