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
Acid Reflux and Mounjaro: Cost, Access, and Managing Side Effects in the UK
Acid reflux (gastro-oesophageal reflux disease or GORD) is one of the most commonly reported side effects when taking Mounjaro (tirzepatide) for weight management. If you're considering this prescription-only weight loss injection or are currently taking it, understanding both the potential side effects and how to access Mounjaro in the UK — including costs — is essential. This guide covers everything you need to know about managing acid reflux while on Mounjaro, plus the real costs and access routes available to UK adults.
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 Cost in the UK: NHS vs Private Access
Mounjaro is available through two routes in the UK: the NHS and private prescription.
NHS access: NICE has approved tirzepatide (Mounjaro) for use within specialist weight management services, but availability is limited. You'll need a referral from your GP to a tier 3 or tier 4 weight management service. This can involve lengthy waiting lists — in many areas, waiting times exceed 12 months. Once approved, the cost to you is covered under your NHS prescription charge (currently £9.65 in England for a one-month supply, or free if you qualify for exemption).
Private prescription cost: Private access through UK-licensed prescribers and GPhC-registered pharmacies typically costs £129–£320 per month depending on your dose. Starting doses (2.5–5 mg) are usually at the lower end; higher maintenance doses (10–15 mg) cost more. You'll pay for a private online consultation (typically £15–£50) and then the Mounjaro KwikPen itself. Some providers offer subscription discounts. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses, which may help you decide whether private access is right for you.
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.
Acid Reflux on Mounjaro: Causes, Management, and Access Options
Acid reflux occurs in approximately 2–5% of people taking Mounjaro during clinical trials, though it's more common at higher doses. It happens because Mounjaro slows how quickly food leaves your stomach, giving stomach acid more time to irritate the oesophagus. If you develop acid reflux, inform your prescriber immediately — they may suggest a dose reduction, dietary changes, or a temporary pause while your body adjusts.
Management strategies: Eat smaller, more frequent meals; avoid acidic and spicy foods; don't eat close to bedtime; stay upright after eating; and discuss antacid use with your GP. Your prescriber might recommend proton pump inhibitors (PPIs) like omeprazole. Track your symptoms using our free progress tracker to identify food triggers and monitor whether symptoms improve over time. If acid reflux persists despite management, discuss continuing Mounjaro with your prescriber.
How to Access Mounjaro: The Private Prescription ProcessAccessing Mounjaro privately in the UK is straightforward. You'll complete an online consultation with a UK-licensed prescriber, answering detailed health questions about your weight, BMI, medical history, and current medications. Use our free BMI calculator to confirm your eligibility — you'll typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure.
Once assessed, a prescription is issued to a GPhC-registered pharmacy, which dispenses your Mounjaro KwikPen. You inject once weekly at home. Your prescriber will manage dose titration — starting at 2.5 mg and increasing every 4 weeks if tolerated. Follow-up consultations (usually every 4–8 weeks) monitor your progress and side effects including acid reflux, nausea, or other common issues. Costs remain consistent monthly, though some providers offer loyalty discounts for longer-term treatment.
- 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.
What causes acid reflux when taking Mounjaro?
Mounjaro slows gastric emptying—how quickly food moves from your stomach to your intestines. This delayed digestion allows stomach acid more time to irritate your oesophagus, causing acid reflux or indigestion. This effect is typically more noticeable at higher doses and often improves as your body adjusts over weeks.
How much does Mounjaro cost on the NHS in the UK?
On the NHS, Mounjaro costs the standard prescription charge (£9.65 in England per month, or free if you qualify for exemption). However, NHS access is limited to specialist tier 3/4 weight management services and involves waiting lists. Private prescription costs are typically £129–£320 monthly depending on your dose.
Can I switch from Mounjaro to Wegovy if I develop acid reflux?
Possibly. Both Mounjaro and Wegovy can cause acid reflux, though the incidence and severity vary. Wegovy (semaglutide) is a single GLP-1 agonist whereas Mounjaro is a dual GIP/GLP-1 agonist—some people tolerate one better than the other. Any medication switch must be managed by your prescriber and requires a new clinical assessment.
What should I do if acid reflux develops while taking Mounjaro?
Contact your prescriber immediately. Management options include: reducing your dose, adjusting your diet (smaller meals, avoiding triggers), taking over-the-counter antacids, or discussing prescription PPIs like omeprazole with your GP. Most people find symptoms improve with dietary changes or a temporary dose pause.
Is Mounjaro cheaper on the NHS or private prescription?
NHS prescription is cheaper (£9.65 or free with exemption), but private access is faster—no waiting list—and offers consistent, reliable supply. Private costs (£129–£320/month) are higher but may be worthwhile if NHS waiting times are very long in your area or you want immediate access.
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.