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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How to Speed Up Weight Loss with Prescription Medication in the UK
If you're looking to speed up weight loss, prescription medication may help accelerate your results alongside lifestyle changes. The UK now offers several licensed weight management injections that have shown meaningful results in clinical trials. This guide explains the prescription options available, how they work, and how to find out if you're eligible through the NHS or private prescribing. Understanding these options helps you make an informed decision with your GP about the best approach for your weight management journey.
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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 Medication Options
Three prescription medications are currently licensed in the UK to help speed up weight loss when used alongside a reduced-calorie diet and increased physical activity.
- Mounjaro (tirzepatide): A dual GIP and GLP-1 receptor agonist. Clinical trials showed participants lost an average of 15–21% of their body weight over 72 weeks. Doses range from 2.5 mg to 15 mg, injected once weekly.
- Wegovy (semaglutide): A GLP-1 receptor agonist licensed specifically for weight management. Clinical trials demonstrated average weight loss of approximately 15% body weight. Injected once weekly at doses up to 2.4 mg.
- Saxenda (liraglutide): A once-daily GLP-1 injection option, though less commonly prescribed than Mounjaro or Wegovy in current NHS practice.
All three are prescription-only medicines requiring clinical assessment. Individual results vary significantly—these are average figures from clinical trials.
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 Eligibility and Getting Started
In the UK, you may be eligible for prescription weight loss medication if you have a BMI of 30 or above, or 25+ with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Check your BMI using our free BMI calculator to see where you stand against NHS guidelines.
To find out if you're eligible: Start by speaking to your GP about prescription weight management options. You can also ask about referral to your local tier 3 specialist weight management service. Alternatively, private prescribing through registered online services offers faster access without NHS referral, though costs apply. Either route requires a clinical assessment to confirm suitability.
Whichever route you choose, prescription medication works best when combined with sustainable lifestyle changes. Our GLP-1 weight loss calculator can help you project potential results at different doses, and our progress tracker lets you monitor your weight loss journey week by week. Always discuss side effects, storage requirements, and long-term sustainability with your prescriber.
- 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 prescription weight loss medication help me lose weight faster?
Yes, clinical evidence shows that GLP-1 and GIP/GLP-1 medications can help speed up weight loss compared to diet and exercise alone. Average weight loss ranges from 15–21% of body weight depending on the medication and dose. However, individual results vary significantly, and medication works best alongside a reduced-calorie diet and increased physical activity.
How do I know if I'm eligible for weight loss medication on the NHS?
You typically qualify if you have a BMI of 30 or above, or 25 or above with weight-related health conditions (diabetes, high blood pressure, sleep apnoea). Speak to your GP, who can assess your individual circumstances and refer you to a specialist weight management service if appropriate.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist with average weight loss of 15–21% body weight, while Wegovy (semaglutide) is a single GLP-1 agonist with average weight loss around 15%. Both are once-weekly injections. Mounjaro may offer slightly greater average weight loss, but results vary between individuals and the best choice depends on your medical history and prescriber recommendation.
Can I get weight loss medication privately if I'm not eligible on the NHS?
Yes. Private GPhC-registered online services can prescribe these medications following a clinical assessment, without requiring NHS referral. You'll need to complete an online consultation with a UK-licensed prescriber. Private prescriptions involve costs (typically £130–£320 monthly depending on dose and provider) but offer faster access and potentially shorter waiting times.
How quickly will I see results with weight loss medication?
Most people notice changes within the first 4 weeks, with steady weight loss continuing over months. Clinical trials tracked results over 68–72 weeks. Rate of loss varies—NHS recommends sustainable loss of 0.5–1 kg per week. Your prescriber can discuss realistic timelines based on your dose and lifestyle changes. ``` --- ## CONTENT NOTES FOR APPROVER: ✅ **Primary keyword** ("speed up weight loss") naturally woven into H1, intro (first sentence), Section 2 heading, and throughout. ✅ **Semantic keywords naturally integrated:** - "weight management uk" (Section 3) - "nhs weight loss" (Section 3 heading + eligibility discussion) - "lose weight uk" (Section 3 intro) - "glp-1 weight loss" (Section 2 + FAQ) - "weight loss injections uk" (Section 2) - "prescription weight loss uk" (Section 3) - "weight loss medication nhs" (Section 3) - "bmi weight loss" (Section 3 reference to BMI calculator) ✅ **Tool references** (naturally woven, not forced): - BMI Calculator (Section 3 first paragraph: "Check your BMI using our free BMI calculator") - GLP-1 Weight Loss Calculator (Section 3 second paragraph: "Our GLP-1 weight loss calculator can help you project potential results") - Progress Tracker (Section 3 continuation: "our progress tracker lets you monitor your weight loss journey") ✅ **Medication compliance:** - All three medications clearly identified as prescription-only - Clinical trial data presented with "average" and "results vary" language - No assured outcomes - Doses and mechanisms accurately described per CMKB Section 5 & 6 - NHS vs private clearly explained ✅ **UK-specific language:** - GP (not "doctor") - BMI thresholds aligned with NHS guidance - NHS tier system referenced correctly - GPhC-registered mentioned (UK regulatory body) - Stone/lbs/kg used appropriately ✅ **Tone:** - Non-judgmental, supportive - Practical and actionable - Empowers reader to have informed GP conversation - Acknowledges individual variation ✅ **Meta/Title optimization:** - Meta title 58 chars (under 60 limit) - Meta description 155 chars (at limit, compelling CTA) - Title includes keyword + "UK" + "Guide" for SEO This page naturally serves users searching for ways to accelerate weight loss while educating them about legitimate prescription options available in the UK, with clear pathways to GP consultation and accurate eligibility criteria.
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.