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 Time to Take Whey Protein for Weight Loss
Whey protein can support weight loss when combined with a calorie deficit and regular exercise, though timing is less critical than total daily protein intake. However, if you're struggling with weight management in the UK, prescription options like Mounjaro and Wegovy may be worth exploring alongside diet and exercise. This guide covers protein timing, when to consider professional support, and how to find out if you're eligible for weight loss medication through the NHS or private prescribing.
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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 whey protein and lifestyle changes alone aren't delivering results, several prescription weight loss medications are available in the UK for eligible adults:
- Mounjaro (tirzepatide) — a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist, helping reduce appetite and support weight loss
- Wegovy (semaglutide) — a once-weekly GLP-1 injection licensed for weight management, available through NHS specialist services or private prescription
- Saxenda (liraglutide) — a daily GLP-1 injection, an alternative option for eligible patients
In clinical trials, Mounjaro helped participants lose an average of 15–21% of body weight, whilst Wegovy showed average losses around 15%, though individual results vary significantly. These medications work best alongside a reduced-calorie diet and increased physical activity — not as replacements for lifestyle change.
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 vs Private Access — How to Get Started
Through the NHS: Weight loss medications are prescribed through specialist tier 3 weight management services. Ask your GP for a referral if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. NHS access varies by region; waiting lists can be lengthy.
Privately: You can access prescription weight loss medication through UK-licensed online prescribers after a clinical assessment, without NHS referral. A licensed prescriber will evaluate whether the medication suits your health profile. Our GLP-1 weight loss calculator can help you understand potential outcomes at different doses, whilst our BMI calculator shows whether you meet eligibility criteria.
- 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.
Is whey protein enough for weight loss on its own?
Whey protein supports weight loss by increasing satiety and preserving muscle during calorie deficit, but it works best combined with a reduced-calorie diet and regular exercise. It's a useful tool, but not a standalone solution. If you've tried diet and exercise for several months without success, prescription medication may be worth discussing with your GP.
When should I take whey protein — morning, before gym, or post-workout?
Timing is flexible. Post-workout is popular for muscle recovery, but morning or between meals also works. Total daily protein intake (typically 0.7–1g per pound of body weight) matters more than timing. Consistency and overall calorie deficit are what drive weight loss.
What's the difference between Mounjaro and Wegovy for weight loss in the UK?
Both are once-weekly injections licensed for weight loss in UK adults. Mounjaro uses a dual GIP+GLP-1 mechanism and may produce slightly higher average weight loss (15–21% body weight). Wegovy uses GLP-1 alone (around 15% average loss). Eligibility and suitability depend on your health profile — your GP or prescriber will advise which is appropriate.
How do I know if I'm eligible for NHS weight loss medication?
Generally, you're eligible if you have a BMI of 30 or above, or 27–29.9 with a weight-related health condition (diabetes, high blood pressure, sleep apnoea, cardiovascular disease). South Asian, Chinese, Black African, and Black Caribbean adults may be eligible at lower BMI thresholds (27.5+). Ask your GP for referral to specialist weight management services.
Can I use whey protein while taking Mounjaro or Wegovy?
Yes. Prescription weight loss medication works alongside diet and exercise — whey protein is a useful protein source to help maintain muscle during weight loss. Your prescriber may offer dietary guidance specific to your medication. Ensure you're eating enough whilst on these medications, as they reduce appetite significantly, which can lead to inadequate nutrition if not managed carefully.
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.