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
Does Mounjaro Increase Heart Rate?
Mounjaro (tirzepatide) is a prescription-only weight management injection that works through a dual GIP and GLP-1 receptor mechanism. People considering this medication often ask whether it affects heart rate. The evidence suggests that heart rate changes with Mounjaro are generally mild and not a primary safety concern, though individual responses vary. Understanding the cardiovascular effects alongside cost and access routes in the UK will help you make an informed decision with your prescriber.
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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.
What Does Clinical Evidence Show About Mounjaro and Heart Rate?
Clinical trials of Mounjaro showed that heart rate changes were uncommon and typically mild. Most participants experienced no significant change, while some reported a modest increase or decrease in resting heart rate — these changes were not considered clinically problematic. Importantly, Mounjaro does not contain stimulants and works differently from older weight loss medications that did increase heart rate.
However, when weight loss occurs rapidly, your body naturally experiences some cardiovascular adjustments. Dehydration, which can occur with gastrointestinal side effects like diarrhoea, may temporarily elevate heart rate. Your GP or prescriber will monitor your cardiovascular health before starting Mounjaro — they may check your baseline heart rate and blood pressure. If you have a pre-existing heart condition, arrhythmia, or are on cardiac medications, it's essential to discuss this with your prescriber, as they will assess individual risk.
You can also use our free BMI calculator to understand your current health context before your clinical assessment.
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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.
Accessing Mounjaro in the UK — NHS and Private Routes
NHS access: Mounjaro is available through specialist tier 3 and tier 4 weight management services. You'll need a GP referral and assessment. Availability and waiting times vary significantly by region — some areas have long waiting lists. The Kwikpen device is supplied free on the NHS once approved.
Private access: You can obtain a Mounjaro prescription privately through an online clinical consultation with a UK-licensed prescriber. The process involves completing a health questionnaire, discussing your medical history, and receiving a prescription if clinically appropriate. Costs typically range from £150–£280 per month depending on the dose. Always use a GPhC-registered pharmacy. Private prescribers will assess your eligibility and cardiovascular health just as thoroughly as NHS services before dispensing tirzepatide.
- 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 Mounjaro cause heart palpitations?
Heart palpitations are not listed as a common side effect of Mounjaro in clinical trials. If you experience palpitations, chest pain, or unusual heart sensations, contact your GP immediately. These could indicate another condition requiring investigation, not necessarily related to Mounjaro itself.
Is Mounjaro safe if I have high blood pressure?
Mounjaro may actually help improve blood pressure in many people due to weight loss. However, if you have hypertension or take blood pressure medication, your prescriber must assess you individually. They may monitor your BP more frequently when starting Mounjaro, and your medications might need adjustment.
How much does Mounjaro cost on the NHS versus privately in the UK?
On the NHS, Mounjaro is free once approved through a specialist service. Privately, costs range from approximately £150–£280 per month depending on your dose. Starting doses (2.5mg) are typically cheaper than maximum doses (15mg). Some private providers offer package discounts for multiple months.
What's the difference between Mounjaro and Wegovy regarding heart rate effects?
Both Mounjaro and Wegovy are well-tolerated with minimal heart rate effects in clinical trials. Mounjaro is a dual GIP and GLP-1 agonist, while Wegovy is a GLP-1 agonist only. Neither is expected to significantly increase resting heart rate, though individual responses vary.
How long does it take to get Mounjaro on the NHS in the UK?
NHS waiting times vary by region and specialist service availability. Some areas have waits of several months to over a year. Private online consultations are typically faster — you may receive a prescription within days if approved. Check your local NHS weight management service for realistic timelines in your area.
Ready to take control of your weight loss journey?
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