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
Natural Weight Loss Pills — What's Actually Available in the UK?
When people search for "natural weight loss pills," they're often looking for effective weight management solutions. In the UK, this typically means prescription medications rather than unregulated supplements. The most evidence-based options available are GLP-1 receptor agonist injections—Mounjaro, Wegovy, and Saxenda—which are prescription-only medicines licensed for weight management by the MHRA. These work with your body's natural appetite-regulating hormones. Understanding what's actually available through NHS or private prescribing, and whether you're eligible, is the first step toward sustainable weight loss UK.
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.
UK-Licensed Prescription Weight Management Options
Three prescription-only medicines are currently licensed for weight management in the UK:
- Mounjaro (tirzepatide) — a dual GIP and GLP-1 receptor agonist, once-weekly injection. Clinical trials showed an average weight loss of 15–21% of body weight over 72 weeks when combined with diet and exercise.
- Wegovy (semaglutide) — a GLP-1 receptor agonist, once-weekly injection. Clinical evidence demonstrated approximately 15% average body weight loss in trials.
- Saxenda (liraglutide) — a GLP-1 receptor agonist, once-daily injection. Typically produces modest weight loss results.
You may be eligible if you have a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. Lower BMI thresholds apply for adults of South Asian, Chinese, Black African, or Black Caribbean heritage. All require a prescription following clinical assessment by a licensed prescriber. Individual results vary significantly.
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.
Accessing Prescription Weight Loss — NHS vs Private
NHS access: Referral to specialist tier 3 or 4 weight management services through your GP. NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS use, but availability varies significantly by region and waiting lists can be lengthy. Specialist services will assess your eligibility and suitability.
Private access: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. No NHS referral needed, but you'll pay privately (typically £129–£320+ monthly depending on dose). Your GP can still provide support alongside private treatment. Before starting any prescription weight loss medication, calculate your BMI using our free BMI calculator above to understand your starting point, and consider tracking your progress with our progress tracker throughout your weight loss journey.
- 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.
Are there any "natural" weight loss pills available without prescription in the UK?
Most unregulated weight loss supplements lack robust clinical evidence. The only medicines with strong evidence for weight management available in the UK are prescription-only GLP-1 medications (Mounjaro, Wegovy, Saxenda). Supplements may be marketed as "natural" but are not the same as clinically-tested prescription medicines. Always check with your GP before starting any supplement.
How do I know if I'm eligible for prescription weight loss medication in the UK?
Use our free BMI calculator on this page to check your starting point. You may be eligible with a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Lower thresholds apply for South Asian and Black heritage adults. Your GP or a licensed prescriber will assess your full medical history to confirm eligibility.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with an average 15–clinically studied weight loss in trials. Wegovy (semaglutide) is a GLP-1 agonist with approximately 15% average weight loss. Mounjaro reaches a higher maximum dose (15mg). Both are once-weekly injections. Clinical trial results suggest Mounjaro may produce slightly greater average weight loss, but individual outcomes vary considerably.
Can I get prescription weight loss medication through the NHS quickly?
NHS access varies significantly by region. Some areas have specialist weight management services available relatively quickly; others have waiting lists of several months to over a year. Your GP can refer you to your local service. If NHS waiting times are long, private prescribing through online services is an alternative option.
Do I need to follow a diet alongside prescription weight loss medication?
Yes. Prescription weight loss medications work best alongside a reduced-calorie diet and increased physical activity. They are not a substitute for lifestyle changes—they support and facilitate them. Our GLP-1 weight loss calculator can help you estimate potential results, and our progress tracker lets you log your weight loss journey alongside dietary and exercise changes.
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.