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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Mounjaro Pain In Right Side — What You Need To Know
Right-sided pain while taking Mounjaro is a concern that needs proper medical evaluation. Although this specific symptom isn't listed as a common side effect in clinical trials, abdominal discomfort can occur during tirzepatide treatment. Since pain localised to the right side could indicate several different conditions — some related to Mounjaro, others unrelated — it's important to understand when to contact your GP and what information to provide. This guide covers what might cause right-sided pain during Mounjaro treatment and how the NHS approach this symptom.
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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.
When Right-Sided Pain May Be Linked To Mounjaro
Mounjaro is a dual GIP and GLP-1 receptor agonist that can affect how your stomach works, potentially causing various abdominal symptoms. Right-sided pain could be related to several Mounjaro effects:
- Gastroparesis — slowed stomach emptying can cause discomfort across the abdomen, including the right side
- Gallbladder issues — clinical data suggests increased gallbladder events in some GLP-1 users; pain under the right rib cage may indicate gallbladder involvement
- Pancreatitis — though rare, severe stomach pain (especially upper abdomen and back) is a medical emergency and requires immediate NHS assessment
- Constipation or gas — very common Mounjaro side effects that can cause localised discomfort
However, right-sided pain may also be unrelated to Mounjaro — appendicitis, kidney issues, muscle strain, or other conditions can cause similar symptoms. Your GP must evaluate the full context.
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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 To Contact Your GP Or NHS 111
Contact your GP immediately or call NHS 111 if you experience: severe, persistent right-sided pain especially if accompanied by vomiting, fever, or back pain; pain that worsens despite rest or paracetamol; jaundice (yellowing of skin/eyes, which suggests gallbladder or liver involvement); or changes in bowel movements or stool colour. Call 999 or go to A&E for sudden, severe abdominal pain, inability to keep food/fluids down, or signs of shock. When you contact NHS services, clearly state you're taking Mounjaro (tirzepatide) and the dose you're on — this helps your GP assess whether your symptoms are medication-related or indicate a separate medical issue.
- 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.
Is right-sided pain a common Mounjaro side effect?
Right-sided pain specifically is not listed as a common side effect in Mounjaro clinical trials. However, stomach pain and abdominal discomfort (affecting various areas) occur in over 10% of users. Right-sided pain could indicate gallbladder involvement, gastroparesis, or an unrelated condition — your GP needs to assess it.
Could my right-sided pain be gallbladder-related?
Possibly. GLP-1 and GIP receptor agonists may increase gallbladder events including gallstones. Pain under the right rib cage, especially after eating fatty foods, or pain with jaundice or pale stools, suggests gallbladder involvement. Contact your GP promptly for evaluation.
What dose adjustments might help if Mounjaro is causing abdominal pain?
Only your prescriber should adjust your Mounjaro dose. If abdominal pain develops, inform them immediately — they may pause your dose, reduce to a previous dose, or switch you to an alternative. Never adjust tirzepatide dose yourself. Your prescriber will also investigate whether your pain is Mounjaro-related or a separate issue.
Should I stop taking Mounjaro if I have right-sided pain?
Do not stop Mounjaro without speaking to your prescriber. Stopping without guidance could affect your treatment plan. Contact your GP or prescriber first — they'll assess your symptoms and decide whether to continue, pause, reduce, or switch your medication.
How is right-sided pain evaluated by the NHS?
Your GP will take a detailed history (when pain started, severity, related symptoms), perform a physical examination, and may order blood tests or imaging (ultrasound, CT) to assess your liver, gallbladder, pancreas, or kidneys. This helps distinguish between Mounjaro-related and unrelated causes.
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