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
Only Losing 1Lb A Week On Mounjaro — What You Need To Know
If you're only losing 1lb per week on Mounjaro, you're not alone — and it's important to understand that weight loss rates vary significantly between individuals. Mounjaro (tirzepatide) is a prescription-only once-weekly injection licensed in the UK for weight management, and whilst clinical trials showed average weight loss of 15–21% of body weight, individual progress depends on many factors including your starting weight, dose, lifestyle, and how your body responds. This guide covers what's typical, why your rate might differ from others, and the UK cost and access options for getting Mounjaro through NHS specialist services or private prescription.
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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 Weight Loss Rates And Cost In The UK
Losing 1lb (approximately 0.45kg) per week is actually considered healthy and sustainable by NHS standards, which recommend losing 0.5–1kg weekly. In the SURMOUNT clinical trials, Mounjaro helped participants lose an average of 15–21% of body weight over 72 weeks — but this breaks down to roughly 0.5–1.5lbs per week depending on starting weight and dose.
- Mounjaro dose matters: At 5mg, average loss was around 15% body weight; at 15mg (maximum dose), around 20.9%. Your prescriber increases your dose gradually over weeks 1–20, so week-to-week loss may vary significantly
- Individual factors: Faster loss is often seen in the first 2–4 weeks (including fluid loss), then stabilises. People with higher starting weights typically lose more weight than those starting closer to overweight thresholds
- Cost varies by access route: NHS prescriptions are free once approved; private mounjaro kwikpen prescriptions typically cost £129–£300+ per month depending on your dose and provider
Track your progress using our free progress tracker to spot patterns over weeks, not days.
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 access: Mounjaro is available through NHS specialist tier 3/4 weight management services following NICE approval. You'll need a referral from your GP, assessment by a specialist team, and prescription through that service. Availability and waiting times vary significantly by region — some areas have waiting lists of 6–18 months. Free once prescribed.
Private access: Through a UK-licensed prescriber via online consultation (no pharmacy name needed — many GPhC-registered pharmacies offer this). The process: complete a health questionnaire, have a clinical assessment call or consultation, and receive a prescription if approved. Private mounjaro uk prescription costs depend on your dose and provider, typically £150–£350 monthly. Compare mounjaro vs wegovy with your prescriber — both require prescription and clinical assessment. Faster access than NHS but you pay directly.
- 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 1lb per week weight loss on Mounjaro normal?
Yes. The NHS recommends 0.5–1kg (1–2lbs) per week as sustainable and healthy. At this rate, you'd expect to lose around 4–5lbs monthly. Clinical trials showed Mounjaro helped participants lose 15–21% body weight over 72 weeks, which translates roughly to this range. Individual progress varies based on starting weight, dose, diet, activity, and metabolism.
Why might my weight loss be slower than others on Mounjaro?
Weight loss depends on your starting weight, current dose (Mounjaro dose titration takes 20 weeks to reach maximum), adherence to a reduced-calorie diet, physical activity level, and individual metabolism. Faster initial loss is common; then weight loss stabilises. Your prescriber can assess whether your dose should be increased or if lifestyle factors need adjustment.
How much does Mounjaro cost privately in the UK?
Private Mounjaro prescriptions typically cost £129–£320+ per month, depending on your dose (starting at 2.5mg, maximum 15mg). Each KwikPen contains 4 weekly injections. NHS prescriptions are free once you're approved through a specialist weight management service, though waiting lists can be long in many regions.
How do I access Mounjaro through the NHS?
Ask your GP for a referral to your local NHS tier 3 specialist weight management service. You'll be assessed for eligibility (BMI ≥30, or ≥27 with weight-related health conditions). If approved, Mounjaro will be prescribed and monitored by the specialist team. Availability and waiting times vary by ICB area. Use our BMI calculator to check your starting point.
What's the difference between Mounjaro and Wegovy for cost and access?
Both are prescription-only and available through NHS specialist services or private prescription. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist with average clinically studied weight loss at maximum dose; Wegovy (semaglutide) is GLP-1 only with around 15% average loss. Private costs are similar (£150–£300+/month). Mounjaro vs wegovy choice depends on your health profile and prescriber recommendation — individual eligibility and effectiveness vary.
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.