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
When Should You Increase Your Mounjaro Dose?
Mounjaro (tirzepatide) is prescribed with a structured dose titration schedule that typically increases every four weeks. In the UK, your prescriber decides whether to escalate based on your tolerance, weight loss progress, and any side effects. Unlike some weight management treatments, there is no one-size-fits-all answer — dose increases depend on your individual clinical response and how well you tolerate each level.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Escalation Schedule vs Wegovy Titration
Mounjaro's official UK dosing schedule starts at 2.5 mg once weekly for four weeks, then typically escalates to 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg (the maximum dose). Each dose is held for a minimum of four weeks before increasing, allowing your body to adjust and your prescriber to assess effectiveness and tolerability.
In the SURMOUNT-1 clinical trial, participants on 15 mg Mounjaro achieved average weight loss of approximately 20.9% of body weight over 72 weeks alongside a reduced-calorie diet and increased physical activity.
Wegovy's dose escalation is faster and reaches a lower maximum: it starts at 0.25 mg and progresses through 0.5 mg, 1 mg, and 1.7 mg, reaching its maximum of 2.4 mg. Wegovy typically escalates weekly initially, then slows to every 4 weeks at higher doses. In STEP-1 trials, semaglutide achieved average weight loss of approximately 14.9% of body weight at the maximum 2.4 mg dose.
The key difference: Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only — this may explain why Mounjaro requires higher doses and a longer titration period.
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.
How Your Prescriber Decides Whether to Increase Your Dose
Your UK prescriber will assess four factors before increasing your Mounjaro dose: weight loss progress (how much you've lost since starting or the last dose increase), tolerability (whether you're managing side effects like nausea or stomach discomfort), clinical response (whether there's a meaningful difference in your appetite or food cravings), and any contraindications or health changes that might affect suitability.
If you're experiencing severe nausea, vomiting, or stomach pain that doesn't improve within a few days, your prescriber may delay escalation or hold you at your current dose longer. This is a clinical decision — never increase your KwikPen dose yourself. Use our free GLP-1 weight loss calculator to track projected progress at different doses, and discuss your results with your prescriber at each review.
Your UK prescriber will assess four factors before increasing your Mounjaro dose: weight loss progress (how much you've lost since starting or the last dose increase), tolerability (whether you're managing side effects like nausea or stomach discomfort), clinical response (whether there's a meaningful difference in your appetite or food cravings), and any contraindications or health changes that might affect suitability.
If you're experiencing severe nausea, vomiting, or stomach pain that doesn't improve within a few days, your prescriber may delay escalation or hold you at your current dose longer. This is a clinical decision — never increase your KwikPen dose yourself. Use our free GLP-1 weight loss calculator to track projected progress at different doses, and discuss your results with your prescriber at each review.
- 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 increase my Mounjaro dose faster than four weeks?
No. The four-week minimum between dose increases is built into the official UK dosing protocol. Faster escalation increases the risk of serious side effects and does not improve outcomes. Your prescriber may extend this interval if you're experiencing tolerability issues.
What happens if I don't lose weight at a particular Mounjaro dose?
Your prescriber may recommend staying at your current dose longer, increasing to the next level, reviewing your diet and physical activity, or (in rare cases) considering whether Mounjaro is the right choice for you. Weight loss plateaus are common and don't always mean you need a higher dose.
Is Mounjaro's maximum 15 mg dose equivalent to Wegovy's 2.4 mg?
Not directly. These are different medications with different mechanisms — Mounjaro is dual GIP+GLP-1, Wegovy is GLP-1 only. Approximate equivalence is sometimes cited as 15 mg Mounjaro ≈ 2.4 mg Wegovy, but only your prescriber can decide which is suitable for you.
Will I experience different side effects at higher Mounjaro doses?
Possibly. Nausea, vomiting, and diarrhoea are dose-dependent and may worsen with escalation. However, many people find these effects improve over time as their body adjusts. Report any severe or persistent side effects to your prescriber before increasing.
How long does it take to reach the maximum Mounjaro dose?
Following the standard four-week intervals between increases, it takes approximately 20–24 weeks (5–6 months) to reach the 15 mg maximum dose from the 2.5 mg starting dose. Your prescriber may slow this timeline if you experience tolerability issues.
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.