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
Mounjaro and Hair Loss — What UK Patients Should Know
Hair loss is a recognised side effect of Mounjaro (tirzepatide), the prescription weight loss injection approved in the UK. Some people experience increased hair shedding whilst taking this weekly weight loss injection, though it's usually temporary. Understanding why this happens, how common it is, and what you can do about it will help you make an informed decision about whether Mounjaro is right for you. This guide explains hair loss in the context of Mounjaro treatment and what the evidence shows.
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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.
Hair Loss on Mounjaro — Why It Happens and How Common It Is
Hair loss during weight loss is well documented in medical literature, and Mounjaro is no exception. When the body undergoes gradual weight management, it experiences physiological stress that can trigger a temporary condition called telogen effluvium — a shift in hair growth cycles that leads to increased shedding. Hair follicles move prematurely from the growth phase into the resting phase, causing hair to shed 2–3 months later.
In clinical trials, hair loss (alopecia) was reported as a common side effect, affecting up to 1 in 10 people taking Mounjaro. However, several important points matter: weight loss itself — not just the medication — causes hair shedding; this side effect is usually temporary and reversible; and many people experience no hair loss at all. The severity varies considerably between individuals depending on genetics, nutritional status, and the speed of weight loss.
Using our free GLP-1 weight loss calculator can help you understand projected weight loss timelines, which may help contextualise potential hair loss risk.
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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.
Accessing Mounjaro in the UK — Cost and Treatment Routes
In the UK, you can access Mounjaro through two routes: NHS specialist weight management services or private prescription. NHS access is through tier 3 or tier 4 specialist services, typically involving a GP referral and often a waiting list of several months. Regional availability varies significantly.
Private prescription routes involve an online consultation with a UK-licensed prescriber, who assesses your eligibility and medical history. If approved, a prescription is issued to a GPhC-registered pharmacy. Private costs typically range from £120–£350 per month depending on your dose and provider. The KwikPen device itself is the same whether accessed via NHS or private routes — only the access pathway and cost differ. Always ensure any prescriber is UK-licensed and the pharmacy is registered with the GPhC.
- 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.
Does Mounjaro cause permanent hair loss?
No. Hair loss caused by gradual weight management (telogen effluvium) is typically temporary and reverses once weight stabilises. Hair usually regrows within 3–6 months after shedding stops. If you have ongoing hair loss after weight loss has plateaued, discuss this with your GP as it may indicate another cause.
Can I prevent hair loss whilst taking Mounjaro?
Ensuring adequate protein intake, maintaining good nutrition (especially iron, zinc, and biotin), staying hydrated, and managing stress may help support hair health. Slower weight loss can reduce shedding risk. However, some hair loss during gradual weight management is difficult to prevent completely. Your GP or a dietitian can provide personalised nutrition advice.
Is hair loss worse with Mounjaro than with Wegovy?
Both GLP-1 medications can cause hair loss as a side effect during gradual weight management. No direct clinical comparison shows one causes significantly more hair loss than the other. Individual experiences vary greatly. Hair loss is linked more to weight loss speed and overall health factors than to the specific medication.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £120–£350 per month depending on your dose (starting at 2.5 mg, up to 15 mg maximum). Prices vary between providers. NHS access through specialist services is free but involves longer waiting times and regional variation in availability.
What should I do if I experience hair loss on Mounjaro?
Speak to your GP or the prescriber managing your Mounjaro treatment. They can assess whether it's telogen effluvium or another cause, review your nutrition, and discuss whether continuing treatment is right for you. In some cases, slowing dose escalation or pausing treatment may be recommended.
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.