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
Can I Stay On 2.5 Mounjaro Long-Term?
Yes, you can stay on 2.5 mg Mounjaro if your prescriber agrees it's working well for you — but most people titrate to higher doses for better results. The 2.5 mg dose is designed as a starting point to help your body adjust and minimise side effects. Whether you remain on this dose long-term depends on your individual response, side effect tolerance, and your prescriber's assessment. In the UK, access to tirzepatide (Mounjaro) is available through NHS specialist weight management services or private prescription following a clinical assessment. Understanding your options and costs will help you make an informed decision.
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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.
Mounjaro 2.5 mg — Starting Dose or Long-Term Option?
Mounjaro 2.5 mg is the starting dose, designed to allow your body to adapt and help you tolerate the medication well. The standard dosing schedule recommends staying on 2.5 mg for 4 weeks before considering an increase. However, if you're experiencing good weight loss results and manageable side effects at this dose, some prescribers may agree to keep you on 2.5 mg longer or indefinitely.
Clinical practice suggests that higher doses (5 mg, 10 mg, 15 mg) typically produce greater weight loss — in trials, the 15 mg dose showed average weight loss of approximately 21% body weight, compared to around 15% at 5 mg. But individual response varies significantly. If you're losing weight steadily at 2.5 mg and prefer to avoid stronger side effects like nausea or diarrhoea, continuing at this dose is a legitimate option worth discussing with your prescriber.
The key question your GP or prescriber will ask: Are you meeting your weight loss goals at this dose? If yes, and side effects are minimal, staying put may be appropriate. If progress has plateaued after several months, titration to a higher dose is typically recommended.
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.
Mounjaro Cost and Access in the UK — NHS vs Private
NHS access: Mounjaro is prescribed through tier 3 specialist weight management services, but availability varies significantly by region and waiting times can be lengthy. Once approved, NHS prescription costs are standard NHS rates (typically £11.65 per item for adults, or free if exempt).
Private prescription: Available through GPhC-registered online pharmacies following a consultation with a UK-licensed prescriber. Costs range from approximately £129–£180 per month for the 2.5 mg dose, depending on provider. Each KwikPen contains 4 doses (4 weeks supply). Private access requires a clinical assessment to confirm you meet eligibility criteria — BMI 30+ or BMI 27–29.9 with weight-related health conditions. Using our GLP-1 weight loss calculator can help you estimate potential outcomes and discuss realistic expectations with your prescriber.
- 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.
Is 2.5 mg Mounjaro enough for weight loss?
For some people, yes — clinical experience shows steady weight loss is possible at 2.5 mg. However, higher doses typically produce greater average weight loss. Your prescriber will assess whether your progress justifies staying at this dose or titrating up. Progress tracking helps — use our free progress tracker to monitor your results objectively over 8–12 weeks.
Can I stay on 2.5 mg Mounjaro indefinitely?
Potentially, yes — if you're experiencing satisfactory weight loss, good tolerability, and your prescriber agrees. However, many people benefit from titrating to higher doses for improved results. This is an ongoing discussion between you and your prescriber based on your individual goals and side effect tolerance.
How much does Mounjaro 2.5 mg cost on the NHS in the UK?
On the NHS, Mounjaro costs £11.65 per prescription item (or free if you're exempt). However, NHS access is through specialist tier 3 services with variable regional availability and waiting lists that can extend several months.
What's the difference between Mounjaro 2.5 mg and staying on it versus Wegovy?
Mounjaro contains tirzepatide (dual GIP + GLP-1 agonist), whilst Wegovy contains semaglutide (GLP-1 only). Both start at lower doses — Wegovy begins at 0.25 mg. Clinical trial data suggests Mounjaro may produce slightly greater average weight loss, though individual results vary. Compare using our BMI calculator to understand your current starting point.
How do I access Mounjaro privately in the UK?
Contact a GPhC-registered online pharmacy offering Mounjaro prescriptions. You'll complete an online health questionnaire and consultation with a UK-licensed prescriber. If approved, they'll issue a prescription that the pharmacy dispenses. Costs vary by provider (typically £129–£180/month) and are payable privately.
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.