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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5 Mg Mounjaro Weight Loss — What Clinical Trial Data Shows
The 5 mg dose is Mounjaro's first escalation step in the weight loss dose schedule. In clinical trials, participants on 5 mg lost an average of around 15% of their body weight over 72 weeks — though individual results vary significantly. This dose is typically used for 4 weeks during the titration phase before escalating to higher doses. Like all Mounjaro doses, 5 mg works by activating dual GIP and GLP-1 hormone pathways, which helps regulate appetite and support feeling fuller after smaller meals. Results depend on individual factors, consistent lifestyle changes, and adherence to the injection schedule.
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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.
How the 5 Mg Dose Fits Into Mounjaro Treatment
The 5 mg Mounjaro dose is the first maintenance step after the starting dose of 2.5 mg. In the standard titration schedule, you take 2.5 mg for weeks 1–4, then increase to 5 mg for weeks 5–8 before further escalations if needed. At 5 mg, clinical trial data from SURMOUNT-1 showed participants achieved approximately clinically studied weight loss on average — though many continued to higher doses (10 mg or 15 mg) for greater results. The 5 mg dose represents a critical point: if side effects are manageable and weight loss progress is satisfactory, some people maintain this dose long-term. Others escalate further every 4 weeks under their prescriber's guidance. Weight loss results at 5 mg depend on reduced-calorie diet adherence, increased physical activity, baseline weight, and individual metabolism. Calculate your personal BMI and potential weight loss trajectory using our free BMI calculator and GLP-1 weight loss calculator to understand realistic targets for your height and starting weight.
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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.
5 Mg Mounjaro Weight Loss — Realistic Expectations
Expecting weight loss on 5 mg requires context: this is an average from clinical trials, and individual outcomes vary widely. Some people see significant results at 5 mg; others require higher doses for the same effect. The weekly weight loss injection works best alongside consistent dietary changes — a reduced-calorie, balanced diet is essential. Typical side effects at 5 mg include nausea, constipation, or reduced appetite, which usually subside within days to weeks. If side effects are severe, your prescriber may keep you on 5 mg longer before escalating. Use our free progress tracker to log weekly weights and monitor your personal response. Remember: Mounjaro is prescription-only and requires ongoing clinical assessment. Your prescriber will review progress at each dose increase and may adjust your treatment plan based on weight loss results and side effects.
- 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.
How much weight will I lose on 5 mg Mounjaro?
Clinical trials showed an average of clinically studied weight loss at 5 mg over 72 weeks — but individual results vary significantly. Some people lose more, others less. Weight loss depends on your starting weight, diet adherence, physical activity, and individual metabolism. Your prescriber can discuss realistic expectations based on your personal circumstances.
How long do you stay on 5 mg Mounjaro?
The standard schedule is 4 weeks on 5 mg before escalating to 7.5 mg. However, if you're achieving good results or experiencing side effects, your prescriber may keep you on 5 mg longer or maintain this dose long-term. Treatment is individualised based on your response and tolerance.
Is 5 mg Mounjaro available on the NHS in the UK?
Mounjaro is available through NHS specialist tier 3/4 weight management services, though access varies significantly by region and waiting lists can be long. Private prescribing is available through GPhC-registered online pharmacies following a clinical assessment.
What's the difference between 5 mg and 10 mg Mounjaro weight loss?
In clinical trials, 10 mg Mounjaro resulted in average weight loss of approximately 19.5% body weight, compared to 15% at 5 mg. Higher doses generally produce greater results, but also carry higher risk of side effects. Dose escalation is guided by your prescriber.
Can I take 5 mg Mounjaro as a long-term maintenance dose?
Yes, some people maintain 5 mg long-term if it produces satisfactory weight loss and side effects are manageable. Others escalate to higher doses for greater results. Your prescriber will assess whether continuing at 5 mg or escalating is best for your individual treatment goals.
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.