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
Tirzepatide 5 Mg: NHS Access and UK Prescribing Information
Tirzepatide 5 mg is the first standard maintenance dose of Mounjaro (tirzepatide), a GLP-1 receptor agonist approved for weight management in UK adults. This dose is typically reached after four weeks of the starting dose, and represents the point where many people begin to see meaningful weight loss effects. Understanding how the NHS prescribes tirzepatide, your eligibility, and the route to access it is essential if you're considering this weight loss injection in the UK. Use our free BMI calculator above to check your starting point, and our GLP-1 weight loss calculator to see projected outcomes at different doses.
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.
NHS Eligibility and Prescribing Pathway for Tirzepatide 5 Mg
In the UK, tirzepatide is prescribed through the NHS only via specialist tier 3 weight management services — you cannot obtain it from your GP directly. Eligibility criteria include:
- BMI of 30 kg/m² or above (obesity), OR
- BMI of 27–29.9 kg/m² with at least one weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, or cardiovascular disease
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply (BMI 27.5 or above)
The NHS prescribing pathway for tirzepatide involves: referral from your GP to a specialist weight management centre, a comprehensive health assessment, and if suitable, initiation at 2.5 mg for the first four weeks. The 5 mg dose is reached in week 5–8, when most people notice appetite reduction and early weight loss. Availability varies significantly by region — some ICBs (Integrated Care Boards) have implemented tirzepatide, whilst others remain on waiting lists or have limited access. NICE (National Institute for Health and Care Excellence) has approved tirzepatide for use within NHS specialist weight management services, but implementation depends on local funding and capacity.
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.
Tirzepatide 5 Mg: Expected Outcomes and Private vs NHS Access
Clinical trial data (SURMOUNT-1) shows that at the 5 mg dose, average weight loss is approximately 15% of body weight over 72 weeks, achieved alongside a reduced-calorie diet and increased physical activity. However, individual results vary significantly — some people see results sooner, others plateau at this dose and require escalation to 7.5 mg or higher.
NHS access involves waiting times (often 6–18 months depending on your region) and requires specialist assessment. Private access is available through UK-licensed online prescribers and GPhC-registered pharmacies, without NHS referral. Private tirzepatide costs roughly £129–£180 per month at the 5 mg dose. Track your progress with our free progress tracker as you adjust doses.
- 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 tirzepatide 5 mg the maximum dose I can take?
No. Tirzepatide can be escalated every 4 weeks up to 15 mg maximum. The 5 mg dose is the first maintenance dose — many people escalate to 7.5 mg, 10 mg, 12.5 mg, or 15 mg depending on weight loss response and tolerability. Your prescriber will guide dose escalation based on your progress and side effects.
How long does it take to reach the 5 mg dose?
Four weeks. You start on 2.5 mg for the first four weeks (weeks 1–4), then move to 5 mg from week 5 onwards. Each dose is given once weekly as an injection via the KwikPen device.
What is the difference between tirzepatide and semaglutide (Wegovy)?
Tirzepatide is a dual GIP and GLP-1 receptor agonist, whilst semaglutide (Wegovy) is a GLP-1 receptor agonist only. This dual mechanism may explain why tirzepatide shows slightly higher average weight loss in clinical trials, though individual response varies. Both are prescription-only in the UK.
Can I get tirzepatide 5 mg through the NHS quickly?
NHS access depends on your region and local tier 3 specialist services capacity. Many areas have waiting lists of 6–18 months. If speed is critical, private online prescribing is available without NHS referral, though this involves out-of-pocket costs.
What are the main side effects at the 5 mg dose?
Common side effects include nausea, diarrhoea, vomiting, constipation, and stomach pain. These typically reduce after a few weeks as your body adjusts. Serious side effects are rare but include severe stomach pain (possible pancreatitis) — seek immediate medical attention if this occurs.
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.