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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Mounjaro Sleep Side Effects — UK Costs and Access
Sleep disturbances are a reported side effect of Mounjaro (tirzepatide), though they're less common than nausea or stomach issues. This guide explains what sleep problems some people experience with this GLP-1 medication, how to access it in the UK through NHS or private routes, and what you can expect to pay. Understanding both the potential effects and the practical steps to get Mounjaro prescribed will help you make an informed decision about whether this weight management injection is right for you.
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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.
Sleep Side Effects and UK Prescription Access
Sleep disturbances reported with Mounjaro include insomnia, difficulty falling asleep, and disrupted sleep patterns. These effects are not listed as "very common" in clinical data but do occur in some users. Sleep issues may be partly related to how Mounjaro affects appetite and gastric function—some people feel less hungry in the evening, which can alter sleep routines. Additionally, the medication's effect on blood sugar regulation may influence sleep quality in people with type 2 diabetes.
To access Mounjaro in the UK, you have two main routes: NHS specialist weight management services or private prescription through an online clinical assessment. NHS access typically requires referral from your GP to a tier 3 specialist service, though availability varies significantly by region and waiting lists can be lengthy. Private prescription allows you to obtain Mounjaro without NHS referral—you complete an online consultation with a UK-licensed prescriber, and if approved, your prescription is dispensed by a GPhC-registered pharmacy. The KwikPen delivery format makes it easy to self-inject once weekly.
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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.
What to Expect: Cost, Timeline, and Assessment
Private prescription costs typically range from £150 to £300 per month depending on your dose and provider, with the 2.5 mg starting dose at the lower end and the 15 mg maximum dose at the higher end. Each KwikPen contains four weekly injections. The online assessment process is straightforward—you answer health questions, declare any medications, and a prescriber reviews your suitability. If approved, your prescription is issued and sent to a pharmacy within 1–2 business days. NHS costs are free at the point of use but involve waiting times and regional variation in availability. Many people choose the private route for faster access, while others prefer NHS routes if they qualify. Using our free GLP-1 weight loss calculator can help you estimate potential outcomes before committing to 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.
Can Mounjaro cause insomnia?
Sleep disturbances, including insomnia, are a reported but uncommon side effect of Mounjaro. If you experience persistent sleep problems after starting tirzepatide, speak to your prescriber—they may adjust your dose, timing of injection, or suggest lifestyle changes to improve sleep quality.
How much does Mounjaro cost privately in the UK?
Private prescription costs range from approximately £150–£300 per month depending on your dose. Starting doses are cheaper than maximum doses. Each KwikPen lasts four weeks. Costs vary slightly between providers but typically include the medication and delivery.
How long does it take to get Mounjaro on the NHS?
NHS access times vary significantly by region. Referral to a tier 3 specialist weight management service can take weeks or months depending on your local ICB. Some regions have longer waiting lists than others. Private prescription is typically faster—usually 1–2 weeks from online consultation to delivery.
What happens during a private online Mounjaro consultation?
You complete a health questionnaire covering your medical history, current medications, allergies, and weight management goals. A UK-licensed prescriber reviews this and decides if Mounjaro is suitable for you. If approved, your prescription is issued and sent to a GPhC-registered pharmacy for dispensing.
Is Mounjaro cheaper on the NHS or private?
NHS Mounjaro is free at the point of use, but availability is limited and waiting times are often long. Private prescription costs £150–£300/month but offers faster access. Consider both cost and waiting time when choosing your route—your GP can advise on NHS eligibility and local waiting times.
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.