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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Weight Loss Pills in Holland and Barrett: What Works in the UK?
Holland and Barrett stocks various weight loss supplements and herbal products, but evidence for their effectiveness is limited. If you're looking for clinically proven weight management support, prescription medications are available in the UK for eligible adults. This guide covers NHS-approved prescription weight loss options, eligibility criteria, and how to access them through your GP or private prescribing services. Whether you're exploring over-the-counter options or want to understand prescription alternatives, we'll help you navigate the choices available.
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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 Prescription Weight Loss Medications
For adults with a BMI of 30 or above, or BMI of 27 to 29.9 with weight-related health conditions, three prescription medications are licensed in the UK for weight management:
- Mounjaro (tirzepatide) — a once-weekly injection that activates dual GIP and GLP-1 pathways. Clinical trials showed average weight loss of 15–21% of body weight at maximum dose (15 mg weekly).
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. STEP clinical trials demonstrated average weight loss of approximately 15% of body weight at the maximum dose (2.4 mg weekly).
- Saxenda (liraglutide) — a once-daily GLP-1 injection, offering a different dosing schedule if once-weekly is not suitable.
All three are prescription-only medicines requiring clinical assessment before being prescribed. Individual results vary significantly, and these medications work best alongside a reduced-calorie diet and increased physical activity. Our GLP-1 weight loss calculator can help you explore potential weight loss ranges at different doses, and our BMI calculator can confirm your eligibility category instantly.
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 Access Prescription Weight Loss Treatment in the UK
NHS route: Ask your GP about referral to a specialist tier 3 weight management service. Availability varies by region, and waiting times can be several months. Your GP can assess whether you meet eligibility criteria and whether prescription weight loss medication is appropriate for you.
Private route: Online prescribing services offering consultations with UK-licensed prescribers. If clinically suitable, a prescription is issued and dispensed by a GPhC-registered pharmacy. This route is faster (typically within days) but involves a private consultation fee and medication costs. Weight-related health conditions that may support eligibility include type 2 diabetes, high blood pressure, high cholesterol, sleep apnoea, or cardiovascular disease.
- 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 Holland and Barrett weight loss pills effective?
Most over-the-counter weight loss supplements sold in supermarkets and health stores have limited clinical evidence. Those with some research (like caffeine or glucomannan) show modest effects. For stronger evidence-based support, prescription medications like Mounjaro and Wegovy demonstrate greater weight loss in clinical trials, though they require medical assessment.
What's the difference between supplements and prescription weight loss medication?
Supplements are regulated as food products with limited safety and efficacy requirements. Prescription medications undergo rigorous clinical trials and regulatory approval. Prescription weight loss drugs like Mounjaro and Wegovy show consistent, measurable results in clinical studies — typically 15–clinically studied weight loss — but require a prescription and clinical assessment.
Can I get prescription weight loss medication on the NHS?
Yes, if you're eligible. Criteria include BMI of 30 or above, or 27–29.9 with weight-related health conditions. Referral goes through your GP to specialist weight management services. NHS availability varies significantly by region, and waiting lists can be lengthy. Your GP can advise on local provision and whether you meet criteria.
How quickly can I access private prescription weight loss treatment?
Private online prescribing services typically offer consultations within days. After online assessment with a UK-licensed prescriber, if approved, your prescription is sent to a pharmacy and dispensed. The entire process can take as little as 3–5 days, compared to months for NHS specialist services.
What's the best way to know if I'm eligible for prescription weight loss medication?
Use our free BMI calculator to find your BMI category. If you're in the overweight or obese range (BMI 27 or above), or have weight-related health conditions, you may be eligible. The next step is a conversation with your GP, who can formally assess eligibility and discuss NHS or private options with 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.