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
Best Supplements For Muscle Growth And Weight Loss
If you're trying to build muscle whilst losing weight in the UK, you've probably wondered about supplements. The truth is, most weight loss and muscle gain happens through diet and exercise — but certain supplements may help support your efforts. This guide covers evidence-based options, what NHS experts recommend, and when prescription weight management options might be more effective than supplements alone. Remember, supplements work best alongside a calorie deficit and strength training, not instead of them.
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.
Evidence-Based Supplements For Muscle And Weight Loss
Protein powder is the most evidence-backed supplement for muscle growth. Whey, casein, or plant-based options help you meet daily protein targets (typically 1.6–2.2g per kg of body weight for muscle building). Research shows adequate protein intake during a calorie deficit preserves muscle whilst fat is lost.
Creatine monohydrate has strong clinical evidence for increasing muscle strength and size when combined with resistance training. A typical dose is 3–5g daily, and it's safe for long-term use.
Caffeine may modestly improve fat loss and exercise performance. Found naturally in coffee and tea, or as supplements (100–200mg doses).
Beta-alanine can support high-intensity exercise performance, potentially helping you train harder and longer.
Important: supplements are not regulated as strictly as medicines in the UK. Check products are third-party tested and from reputable manufacturers. Use our free BMI calculator to track your baseline, then monitor progress over 8–12 weeks.
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.
When Prescription Weight Management May Be More Effective
If you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions, prescription weight loss medication may be more effective than supplements alone. GLP-1 weight loss injections like Wegovy (semaglutide) have clinical trial data showing an average weight loss of around 15% of body weight — significantly more than supplements typically achieve. Prescription options work alongside diet and exercise, not instead of them, and require a clinical assessment from a GP or licensed prescriber.
For weight management in the UK, the NHS recommends starting with lifestyle changes (diet, exercise, behavioural support) in tier 1–2 services. Tier 3 specialist services may offer prescription medication if appropriate. Try our GLP-1 weight loss calculator to explore potential outcomes if you're eligible for prescription treatment.
- 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 supplements alone help you lose weight and gain muscle?
Supplements can support weight loss and muscle gain but are not sufficient alone. Research shows diet quality, calorie deficit, and resistance training are the foundation. Supplements like protein and creatine enhance results when combined with proper training and nutrition, not replace them.
Is whey protein powder safe for long-term use?
Yes, whey protein powder is safe for long-term use in healthy adults when used as directed. It's a food product, not a medicine. Ensure you drink enough water and get adequate fibre from whole foods. If you have kidney disease, consult your GP before high-protein supplementation.
How long does it take to see results from supplements?
Protein and creatine typically show noticeable effects within 4–8 weeks when combined with consistent strength training and a proper diet. Fat loss results depend mainly on maintaining a calorie deficit, which usually shows progress within 2–4 weeks when tracked properly. Use our progress tracker to log changes over time.
Are weight loss supplements regulated in the UK?
Supplements are less strictly regulated than medicines in the UK. The Food Standards Agency (FSA) and the Competition and Markets Authority monitor false claims, but third-party testing is not mandatory. Choose products from reputable brands and look for third-party certification badges.
What's the difference between supplements and prescription weight loss medication?
Supplements like protein and creatine support muscle and weight goals but have modest effects. Prescription medications like Wegovy (GLP-1 injections) have clinical trial evidence for significant weight loss (average 15% body weight) and require a GP assessment. Supplements are available without prescription; medications require clinical assessment and prescription from a licensed prescriber.
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.