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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New Shot To Lose Weight — What Options Are Available in the UK?
If you've heard about new weight loss shots available in the UK, you're not alone. Several prescription injection options are now licensed for weight management, alongside traditional approaches. This guide covers all your options — from free NHS support to prescription medications — so you can make an informed decision with your GP about the right approach for your circumstances.
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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.
Weight Loss Options Available in the UK
The new weight loss shots you may have heard about are GLP-1 and GIP/GLP-1 receptor agonist injections. These include Wegovy (semaglutide) and Mounjaro (tirzepatide) — both prescription-only medicines licensed in the UK for weight management in adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions.
However, weight loss shots are just one option within a broader UK weight management pathway:
- Tier 1: Self-help and free digital tools (like our free BMI calculator and weight converter above)
- Tier 2: NHS-funded behaviour change programmes and community support
- Tier 3: Specialist NHS weight management services where prescription medications may be prescribed
- Tier 4: Bariatric (weight loss) surgery for severe obesity
Sustainable weight loss uk requires choosing an approach that fits your health, lifestyle, and circumstances. Each option has different effectiveness, costs, and requirements.
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.
How to Choose the Right Weight Loss Approach
The right approach depends on several factors: your current BMI and health conditions, whether you've tried lifestyle changes before, your budget, and how much medical support you need. Start by checking your BMI using our free BMI calculator on this page — this helps determine which options you're eligible for.
If you're interested in prescription weight loss treatment, your GP can refer you to a specialist NHS tier 3 weight management service, though waiting times vary by region. Alternatively, private prescription weight loss is available through online assessment. For most people, lose weight safely means combining your chosen approach with sustainable lifestyle changes — diet, physical activity, and behaviour support.
Before starting any weight loss method, have a conversation with your GP. They can assess your personal health, discuss the evidence for different approaches, and help you choose the best option. Our free GLP-1 weight loss calculator can help you understand potential outcomes with injection treatments, and our progress tracker lets you log your weight loss journey regardless of which method you choose.
- 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 exactly are the new weight loss shots available in the UK?
The newest weight loss injections licensed in the UK are Mounjaro (tirzepatide) and Wegovy (semaglutide). Both are GLP-1 or GLP-1/GIP receptor agonist injections given once weekly. They are prescription-only medicines requiring clinical assessment. In clinical trials, they helped participants lose an average of 15–21% of body weight alongside lifestyle changes — though individual results vary significantly.
Are weight loss shots available on the NHS?
Yes, NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for use within NHS specialist tier 3 weight management services. Access is through referral from your GP to a specialist service, not standard GP prescription. Availability and waiting times vary considerably by region (NHS Integrated Care Board). Private prescription is also available through licensed UK providers following an online clinical assessment.
How do I know if I'm eligible for a weight loss injection?
You may be eligible if you have a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with a weight-related health condition (like type 2 diabetes, high blood pressure, or sleep apnoea). For people of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply due to higher health risks at lower weights. Always discuss eligibility with your GP.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP/GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Mounjaro showed slightly higher average weight loss (up to 21% vs 15%), but both are effective. Both require a prescription and clinical assessment. Your prescriber will help determine which is more suitable for you based on your individual health.
What if I don't want to try a weight loss injection?
There are many effective alternatives. Free NHS support includes tier 1 digital tools and tier 2 community behaviour change programmes. You can also lose weight through sustained calorie deficit (typically 500 kcal/day for 0.5 kg weekly loss), dietary approaches like Mediterranean diet, and increased physical activity. Prescription medications like Saxenda (daily injection) are also available. Your GP can discuss the nhs weight loss programme options suited to you.
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.