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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Tattoo Weight Loss: UK Prescription Medication Options
If you're considering weight loss and wondering about tattoo aftercare alongside your weight management plan, you're not alone. In the UK, several prescription medications are now available to support sustainable weight loss for eligible adults. These include once-weekly injections like Mounjaro and Wegovy, which work by regulating appetite and supporting healthier eating habits. Understanding your options—whether through the NHS or private prescription—is the first step toward achieving your health goals. Our free BMI calculator can help you assess where you currently stand and whether you might be eligible for prescription weight management support.
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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.
UK-Licensed Weight Loss Medications Available Now
Three prescription-only medications are currently licensed in the UK for weight management: Mounjaro (tirzepatide), Wegovy (semaglutide), and Saxenda (liraglutide). Both Mounjaro and Wegovy are once-weekly injections, whilst Saxenda is a daily injection. These are GLP-1 receptor agonist medications (or dual GIP/GLP-1 in Mounjaro's case) that work by helping regulate appetite and supporting fullness after meals.
Eligibility for prescription weight loss medication in the UK includes:
- Adults with a BMI of 30 kg/m² or above, OR
- Adults with a BMI of 27–29.9 kg/m² with weight-related health conditions (type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease)
- For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply
In clinical trials, these medications supported average weight loss of 15–21% of body weight when combined with lifestyle changes—though individual results vary significantly. Your GP or a licensed prescriber will assess whether medication is suitable for your personal circumstances.
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.
NHS vs Private: How to Access Weight Management Support
In the UK, you can access prescription weight loss medication through two routes: NHS specialist services or private online prescribing.
NHS route: Ask your GP for a referral to your local tier 3 specialist weight management service. NHS access is available but availability and waiting times vary significantly by region (ICB). Some areas may have waiting lists of several months.
Private route: Licensed online prescribing services offer consultations with UK-registered prescribers. If clinically appropriate, a prescription is issued and dispensed by a GPhC-registered pharmacy. This typically takes days rather than months. Our free GLP-1 weight loss calculator can help you explore projected outcomes at different doses to discuss with your prescriber. Try our weight converter and progress tracker to monitor your current weight and log your journey as you progress.
- 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.
Am I eligible for prescription weight loss medication in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. Lower thresholds apply for certain ethnic backgrounds. Your GP or a licensed prescriber can assess your individual eligibility following a clinical consultation.
How much weight can I expect to lose with Mounjaro or Wegovy?
In clinical trials, Mounjaro supported average weight loss of 15–21% of body weight, whilst Wegovy supported around 15% average loss. However, individual results vary significantly. These medications work best alongside a reduced-calorie diet and increased physical activity. Your prescriber can discuss realistic expectations for your situation.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro starts at 2.5 mg and goes up to 15 mg weekly; Wegovy starts at 0.25 mg and reaches a maximum of 2.4 mg weekly. Both are once-weekly injections. Your prescriber will recommend the most appropriate option for you.
Can I get prescription weight loss medication on the NHS?
Yes, but access is through specialist tier 3 weight management services via NHS referral from your GP. Availability varies by region, and waiting lists can be lengthy. Some areas may take several months. Private online prescribing offers faster access if you're eligible and choose to pay privately.
What side effects should I expect with weight loss injections?
Common side effects include nausea, diarrhoea, constipation, and stomach discomfort—especially when starting or increasing doses. These often improve over time. Serious side effects are rare but can include severe stomach pain (possible pancreatitis) or allergic reactions. Always discuss potential side effects with your prescriber before starting medication.
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.