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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Thyroid And Mounjaro — UK Cost And Access Guide
If you have a thyroid condition and are considering Mounjaro (tirzepatide) for weight management, understanding how to access it in the UK and what it costs is essential. Mounjaro is a prescription-only weight loss injection that works differently from other GLP-1 medications — it's a dual GIP and GLP-1 receptor agonist. Access in the UK is available through both NHS specialist services and private online prescribing routes, with costs and availability varying significantly depending on which path you choose.
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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.
How Much Does Mounjaro Cost In The UK?
Private prescription costs for Mounjaro in the UK typically range from £129 to £320 per month, depending on your dose and provider. Mounjaro is dispensed as a KwikPen — a pre-filled pen containing four weekly doses (one month's supply). The cost structure works like this: lower starting doses (2.5 mg and 5 mg) are generally cheaper, while higher maintenance doses (10–15 mg) cost more. Some private providers bundle the initial clinical consultation fee into the monthly cost, while others charge separately — expect £40–£100 for an initial online assessment.
- NHS access: If prescribed through NHS specialist weight management services, Mounjaro is funded by the NHS — no direct cost, though waiting lists can be long (many regions have 12+ month waits)
- Private access: Requires ongoing prescription costs plus regular follow-up consultations (typically £30–£60 every 3–6 months)
- Dose titration: As your dose increases, your monthly cost may increase — most people spend 4–6 months titrating from 2.5 mg to their target dose
Always clarify the exact cost structure before starting treatment, as prices vary by provider and dose.
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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.
NHS Vs Private Routes To Access Mounjaro
NHS route: Available through tier 3 specialist weight management services via GP referral. You'll be assessed against NICE eligibility criteria (BMI 30+ or 27+ with weight-related conditions like thyroid disease). The assessment process includes blood tests, cardiovascular screening, and checks for contraindications. However, NHS availability is extremely variable — some regions have dedicated services, others have months-long waiting lists or limited capacity.
Private route: Faster access through online clinics with UK-licensed prescribers. You'll complete an online health questionnaire and have a brief video or telephone consultation. If approved, your prescription is sent to a GPhC-registered pharmacy. This typically takes 1–2 weeks from consultation to first dose, with no NHS referral needed. Use our GLP-1 weight loss calculator to estimate potential outcomes with different doses while you're deciding which route suits you.
- 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 get Mounjaro on the NHS if I have a thyroid condition?
Yes, thyroid disease (including hypothyroidism) is a recognised weight-related health condition that may make you eligible for NHS Mounjaro. You'll need a GP referral to your local tier 3 specialist weight management service for assessment. NICE guidance recognises thyroid conditions as a qualifying comorbidity, but actual availability depends on your ICB and regional NHS capacity.
How does Mounjaro interact with thyroid medication?
Mounjaro may slow gastric emptying and reduce absorption of oral medications, including some thyroid replacements. If you take levothyroxine or other thyroid medication, inform your prescriber — they may recommend taking it separately from food and other medications, or adjusting timing. You'll need thyroid function tests (TSH and free T4) monitoring while on Mounjaro to ensure your thyroid medication remains effective.
What's the difference between Mounjaro and Wegovy for thyroid patients?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only — Mounjaro's dual mechanism may result in slightly greater weight loss on average. Both can affect medication absorption similarly. Cost and access are similar in the UK. Your prescriber will recommend based on your individual health profile, including thyroid status and any other conditions.
Do I need repeat blood tests while on Mounjaro?
Yes. Your prescriber will arrange baseline blood tests before starting Mounjaro, including thyroid function tests (TSH), kidney function, liver function, and fasting glucose. While on treatment, you'll need repeat monitoring — typically every 6–12 months, more frequently if you have thyroid disease or diabetes. This is essential to ensure your thyroid medication dose remains appropriate and that Mounjaro isn't affecting your metabolic health.
Can I switch from Wegovy to Mounjaro on the NHS?
Possibly, but it depends on your NHS service. Some tier 3 services offer both medications and can switch you if one isn't working well. Others may only have one available. If you're private, switching is simpler — your prescriber can arrange a prescription for Mounjaro instead. There's no official conversion chart between the two, so any switch will involve starting at a lower Mounjaro dose and titrating up carefully under medical supervision.
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.