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 You Take Mounjaro Early in the UK?
Taking Mounjaro early—meaning starting at a higher dose or skipping the standard four-week titration steps—is not recommended without medical guidance. The standard UK dosing protocol exists to help your body adjust and minimise side effects. However, access to Mounjaro itself can happen quickly through private prescription routes, and your prescriber may adjust your dose schedule based on your individual health. This guide explains UK eligibility, how to access Mounjaro, and what the dose titration process actually involves.
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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 Dose Titration and Early Access in the UK
Mounjaro dose titration is a four-week escalation schedule designed to help your body adapt to the medication. Each weekly injection requires four weeks at that dose before moving to the next level:
- Weeks 1–4: 2.5 mg (starting dose)
- Weeks 5–8: 5 mg
- Weeks 9–12: 7.5 mg
- Weeks 13–16: 10 mg
- Weeks 17–20: 12.5 mg
- Week 21+: 15 mg (maximum)
Rushing through titration increases nausea, vomiting, and gastrointestinal side effects significantly. Most UK prescribers follow this schedule strictly because clinical evidence supports it. If you're experiencing inadequate results at your current dose, your prescriber may move you to the next dose at your next four-week review—but skipping doses entirely is not standard practice. Access to Mounjaro through private prescription can be faster than NHS routes, but once prescribed, the dosing protocol remains the same.
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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.
NHS vs Private Access and Cost Expectations
NHS access to Mounjaro for weight management goes through tier 3 specialist weight management services via GP referral. This is free but waiting lists are lengthy in many areas—often several months. NICE approved tirzepatide for NHS use, but regional availability varies significantly.
Private access is faster: complete an online clinical assessment with a UK-licensed prescriber, receive a prescription if eligible, and have Mounjaro dispensed by a GPhC-registered pharmacy. Private costs typically range from £130–£320 per month depending on your current dose—2.5 mg and 5 mg doses cost less than higher doses. Your prescriber will still apply the standard four-week titration protocol. Using our free GLP-1 weight loss calculator can help you understand projected timelines and costs across different doses before starting.
- 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.
Can I start Mounjaro at a higher dose to skip early side effects?
No. The four-week titration is standard across NHS and private prescribing because it minimises side effects and allows your body to adjust safely. Starting at 2.5 mg is mandatory. Your prescriber may adjust timings based on individual tolerance, but skipping doses is not recommended and not standard practice in the UK.
How quickly can I access Mounjaro through private prescription in the UK?
Private prescription timelines are typically 2–7 days from online consultation to dispensing, depending on the provider. NHS access through specialist services is usually 3–12 months due to waiting lists. Both routes require a four-week titration protocol once started.
What's the difference between Mounjaro and Wegovy for early access?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are UK-licensed GLP-1 medications available through private prescription and NHS specialist services. Mounjaro is a dual GIP/GLP-1 agonist and showed higher average weight loss (~15–21%) in clinical trials; Wegovy is GLP-1 only (~15%). Both require the same titration approach and clinical assessment.
Will taking Mounjaro early mean I lose more weight faster?
No. Accelerating the dose schedule doesn't lead to faster weight loss—it just increases side effects without benefit. Weight loss results depend on your current dose, dietary adherence, and physical activity. Our GLP-1 weight loss calculator can help you estimate realistic timelines based on your dose.
What if I'm on NHS Mounjaro and want to progress faster?
You cannot self-escalate doses. Your NHS specialist service will review your progress every 4–12 weeks and adjust your dose according to standard protocols if appropriate. If you're not seeing results, discuss this with your prescriber rather than taking Mounjaro early or at higher doses unsupervised.
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.