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
Amino Acids for Weight Loss — What the Evidence Shows
Amino acids are often promoted as a weight loss supplement, but the evidence for their effectiveness is limited. While amino acids play a role in metabolism and muscle maintenance, they're not a proven standalone solution for weight management. If you're interested in weight management in the UK, there are evidence-backed approaches available — including prescription medications for eligible adults. This guide explains what amino acids do, and how they compare to clinically proven weight loss options available through the NHS and private prescription.
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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 Options
If you have a BMI of 30 or above, or 27 or above with weight-related health conditions, you may be eligible for prescription weight loss medication in the UK. The main options available are:
- Mounjaro (tirzepatide) — a once-weekly injection that activates two hormone pathways (GIP and GLP-1) to help reduce appetite and support feeling fuller after meals. Clinical trials showed average weight loss of approximately 15–21% of body weight over 72 weeks.
- Wegovy (semaglutide) — a once-weekly GLP-1 receptor agonist injection. Clinical trials showed average weight loss of around 15% of body weight.
- Saxenda (liraglutide) — a daily GLP-1 injection, approved for weight management in the UK.
These are prescription-only medicines requiring clinical assessment. Unlike supplements, they have strong clinical evidence backing their effectiveness for weight management. Individual results vary, and they work best alongside reduced-calorie diet and increased physical activity.
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 Weight Loss Treatment in the UK
You can access prescription weight loss medication through two routes in the UK:
- NHS route: Ask your GP for a referral to your local tier 3 specialist weight management service. NHS funding varies by region, and waiting lists can be lengthy.
- Private route: Online consultations with UK-licensed prescribers, followed by prescription dispensing through GPhC-registered pharmacies. Available without NHS referral.
Your GP or a licensed prescriber will assess whether prescription weight loss medication is appropriate for you based on your BMI, health conditions, and medical history. Use our free BMI calculator above to check your personal BMI as a starting point for this conversation.
- 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.
Do amino acid supplements actually help with weight loss?
Limited scientific evidence supports amino acids as a standalone weight loss tool. While amino acids are essential for muscle maintenance and metabolism, studies show modest or no significant weight loss benefit compared to a calorie-controlled diet alone. They may support muscle preservation during weight loss, but are not a proven weight loss medication.
What is the difference between amino acid supplements and prescription weight loss medication?
Amino acid supplements are nutritional products with limited weight loss evidence. Prescription weight loss medications like Mounjaro and Wegovy are clinically proven to support significant weight loss (15–21% body weight in trials). They require a prescription, clinical assessment, and are only available to eligible adults.
Am I eligible for prescription weight loss medication on the NHS?
You may be eligible if you have a BMI of 30 or above, or 27 or above with weight-related conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. Ask your GP about a referral to a specialist weight management service. Eligibility varies by region.
How much does prescription weight loss medication cost privately in the UK?
Private prescription weight loss medication typically costs between £129 and £320 per month depending on the medication, dose, and provider. This is in addition to the consultation fee charged by the prescriber. Costs vary between providers.
Can I use amino acids alongside prescription weight loss medication?
If prescribed weight loss medication, speak to your prescriber or pharmacist before adding amino acid supplements. While generally safe together, your prescriber needs to know all supplements you're taking to monitor for interactions and ensure the medication works effectively.
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.