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
Private Weight Loss Injections in the UK
Private weight loss injections are prescription-only medications available through private prescribers without waiting for NHS referral. In the UK, licensed options include Wegovy (semaglutide) and Mounjaro (tirzepatide), both once-weekly injections that may help support weight management alongside diet and exercise. These medications work by activating natural hormone pathways that regulate appetite and fullness. Access varies between NHS specialist services (with waiting lists) and private online prescribing (available without referral). This guide explains how private weight loss injections work, eligibility criteria, costs, and what to expect.
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.
How Private Weight Loss Injections Work
Private weight loss injections are GLP-1 receptor agonists or GIP/GLP-1 agonists that mimic natural hormones produced in your gut. Wegovy (semaglutide) activates the GLP-1 pathway, whilst Mounjaro (tirzepatide) activates both GIP and GLP-1 pathways — a dual mechanism that may offer enhanced support.
These medications may help by:
- Reducing appetite and food cravings
- Making you feel fuller after smaller meals
- Slowing how quickly food leaves your stomach
- Supporting better blood sugar control
In clinical trials, participants using weight loss injections lost an average of 14.9% to 21% of their body weight over 68 weeks, alongside a reduced-calorie diet and increased physical activity. Individual results vary significantly — some people lose more, some less. These are prescription-only medicines; you cannot buy them over-the-counter.
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.
Private Access vs NHS — How They Differ
NHS route: Referral to a specialist tier 3 or tier 4 weight management service through your GP. Availability and waiting times vary considerably by region (ICB). In many areas, waiting lists extend to months or years.
Private route: Online consultation with a UK-licensed prescriber (not through your GP). If approved following assessment, a prescription is dispensed by a GPhC-registered pharmacy. No NHS referral needed. Private prescriptions typically cost £129–£320 per month depending on dose and provider. Check that any service you use employs UK-licensed prescribers and uses GPhC-registered pharmacies.
To assess your personal eligibility and which route suits you, use our free BMI calculator above to check your current BMI category. Your GP can also advise on NHS options.
Eligibility and What to ExpectYou may be eligible for private weight loss injections if you have:
- A BMI of 30 kg/m² or above (obesity)
- A BMI of 27–29.9 kg/m² with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, cardiovascular disease)
- Lower BMI thresholds if you are of South Asian, Chinese, Black African, or Black Caribbean heritage (evidence shows higher health risks at lower BMI)
A prescriber will assess your medical history, current medications, and suitability during an online consultation. You cannot have these injections if you are under 18, pregnant, breastfeeding, or have a history of thyroid cancer. Side effects are common and include nausea, diarrhoea, and constipation — these often improve over time. Track your weight loss journey using our free progress tracker alongside 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.
Are private weight loss injections safe?
Yes, when prescribed by a qualified UK-licensed prescriber following proper clinical assessment. Both Wegovy and Mounjaro are licensed medicines with established safety profiles from clinical trials. Side effects are common but usually manageable. Serious side effects are rare. Your prescriber will review your medical history to ensure suitability. Never use weight loss injections without clinical assessment.
How much do private weight loss injections cost in the UK?
Private weight loss injections typically cost £129–£320 per month depending on the medication, dose, and provider. Initial consultations cost £45–£100. Costs rise as your dose increases. NHS access is free if available through your local weight management service, but waiting lists can be very long. Some private providers offer payment plans.
Can I get private weight loss injections without seeing my GP?
Yes. Private weight loss injections are available through private online prescribers without GP referral. You complete an online consultation and medical questionnaire. A UK-licensed prescriber reviews your information and issues a prescription if you are eligible. Ensure any service uses GMC-registered prescribers and GPhC-registered pharmacies.
What's the difference between Wegovy and Mounjaro?
Both are once-weekly injections licensed for weight management in the UK. Wegovy (semaglutide) activates one hormone pathway (GLP-1). Mounjaro (tirzepatide) activates two pathways (GIP and GLP-1). In clinical trials, Mounjaro showed slightly higher average weight loss (up to 21% vs 15%). Both require prescription and clinical assessment. Your prescriber will advise which is suitable for you.
Can I use weight loss injections without changing my diet?
Weight loss injections work best alongside a reduced-calorie diet and increased physical activity. Clinical trials showed results when participants combined injections with lifestyle changes. Using an injection alone without diet or exercise modifications is unlikely to produce significant results. Your prescriber will discuss diet, activity, and behavioural support as part of your weight loss plan.
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.