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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When To Increase Your Mounjaro Dose
Knowing when to go up a dose on Mounjaro is an important part of your weight management journey. Your prescriber will guide you on dose titration based on how you respond to the medication and any side effects you experience. The timing and frequency of dose increases differ between Mounjaro and Wegovy, and individual factors play a role in determining the right dose for you.
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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 vs Wegovy Dosing: Key Differences
Mounjaro (tirzepatide) and Wegovy (semaglutide) follow different dose escalation schedules because they have different mechanisms and potencies. Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy is a GLP-1 agonist only. This means Mounjaro's starting and maximum doses are higher.
Mounjaro dosing: You start at 2.5 mg weekly for weeks 1–4, then increase by 2.5 mg every 4 weeks until you reach your target dose (maximum 15 mg weekly). Wegovy dosing: You start at 0.25 mg weekly for weeks 1–4, then increase by 0.25–0.5 mg every 4 weeks until reaching 2.4 mg weekly (maximum dose).
SURMOUNT clinical trial data showed Mounjaro participants lost an average of 20.9% of body weight at the 15 mg dose, whilst STEP trial data for Wegovy showed approximately 14.9% average weight loss at the 2.4 mg dose. However, individual results vary significantly and both medications work best alongside a reduced-calorie diet and increased physical activity. Your prescriber will decide the right pace for your dose increases based on your response and tolerance.
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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.
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When Your Prescriber Will Increase Your Dose
Your GP or prescriber will assess whether to increase your Mounjaro dose based on four key factors: your weight loss response, side effect tolerance, how you are managing with current symptoms, and your overall health. Dose increases always happen at minimum 4-week intervals — you should never increase more frequently than this. If you are tolerating a dose well but losing weight steadily, your prescriber may increase you on schedule. If you are experiencing significant nausea, vomiting, or other side effects, they may delay the increase or keep you at your current dose longer.
Some people reach their optimal dose before the maximum (15 mg for Mounjaro) — this is normal and means you don't need to keep increasing. Your prescriber will help you find the dose that works best for your health goals and side effect profile. Use our GLP-1 weight loss calculator to estimate potential results at different doses, and track your progress with our free progress tracker to monitor how you're responding over time.
- 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 often does Mounjaro dosing increase happen?
Mounjaro doses increase every 4 weeks if tolerated well. You start at 2.5 mg weekly and increase by 2.5 mg increments (so weeks 1–4 at 2.5 mg, weeks 5–8 at 5 mg, weeks 9–12 at 7.5 mg, etc.). Your prescriber may slow or pause increases based on side effects or response.
Is Mounjaro dosing faster than Wegovy?
Yes. Mounjaro reaches higher doses (maximum 15 mg) compared to Wegovy (maximum 2.4 mg), but the 4-week interval between dose increases is the same for both. The dose increments are larger for Mounjaro (2.5 mg steps) than Wegovy (0.25–0.5 mg steps), so titration progresses faster in absolute terms.
What if I'm not losing weight on my current Mounjaro dose?
If you are not seeing weight loss after 4–8 weeks at your current dose, your prescriber may recommend increasing to the next dose. However, they will also assess your diet, physical activity, and any medications that might interfere. Weight loss is not assured, and results vary between individuals.
Can I skip a Mounjaro dose increase?
Yes. If you are experiencing troublesome side effects or are satisfied with your weight loss at your current dose, your prescriber can keep you at that dose long-term. You do not have to reach the maximum 15 mg dose. The goal is finding the dose that works best for your health and tolerability.
How does Mounjaro's dose titration compare to Saxenda?
Saxenda (liraglutide) is a daily injection with a maximum dose of 3 mg, whilst Mounjaro is a weekly injection with a maximum of 15 mg. Saxenda reaches its maximum dose over approximately 4–5 weeks of daily increases, whereas Mounjaro takes longer (approximately 20 weeks) due to the 4-week intervals between increases.
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.