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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Does Mounjaro cause more sweating than Wegovy?
Sweating is not listed as a common or very common side effect of either Mounjaro (tirzepatide) or Wegovy (semaglutide) in UK clinical data. However, both GLP-1 and dual GIP/GLP-1 medications can cause gastrointestinal side effects like nausea and vomiting, which may indirectly trigger sweating in some people. This comparison explores the side effect profiles of both medications, the clinical trial evidence, and how individual responses vary. Use our free GLP-1 weight loss calculator to explore potential outcomes with either medication.
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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.
Clinical Trial Data: SURMOUNT vs STEP Sweating Evidence
Neither Mounjaro nor Wegovy lists sweating as a primary side effect in UK clinical trials. The SURMOUNT-1 trial for tirzepatide (Mounjaro) reports very common side effects as nausea, diarrhoea, vomiting, and constipation — sweating is not mentioned as a notable adverse event. The STEP-1 trial for semaglutide (Wegovy) similarly shows nausea and gastrointestinal symptoms as predominant, with no sweating listed among common effects.
However, indirect sweating can occur if someone experiences severe nausea or vomiting, as the body may sweat in response to gastrointestinal distress. This would be considered a secondary effect rather than a direct medication effect. Both medications work via GLP-1 receptor activation (Mounjaro also activates GIP receptors), but neither mechanism directly triggers increased perspiration in the clinical data published by MHRA-approved sources.
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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.
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Why Gastrointestinal Side Effects Matter More Than Sweating
For most people taking Mounjaro or Wegovy, the main concern is nausea, vomiting, and digestive changes — not sweating. These GI effects typically occur in the first 4–8 weeks and may improve as the body adjusts. If you experience sweating while taking either medication, it is more likely related to nausea response or dose adjustment rather than a direct effect of the tirzepatide or semaglutide itself.
Your prescriber will assess which medication suits you based on your full health profile, not sweating risk. Both require a clinical assessment before prescription. Try our BMI calculator to understand your baseline health status, and discuss any side effect concerns with your GP or licensed prescriber before starting 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.
Is sweating a known side effect of Mounjaro?
Sweating is not listed as a common or very common side effect of Mounjaro in UK clinical trials or the product information. Very common side effects are nausea, diarrhoea, vomiting, and constipation. If sweating occurs, it is typically secondary to gastrointestinal symptoms rather than a direct medication effect.
Does Wegovy cause sweating more than Mounjaro?
No. Clinical trial data for Wegovy (STEP trials) does not list sweating as a common side effect either. Both medications have similar GI side effect profiles dominated by nausea and digestive changes. Individual responses vary, and sweating would be rare and indirect in either case.
What is the main difference between Mounjaro and Wegovy mechanisms?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 receptor agonist only. This mechanism difference affects appetite regulation pathways but does not explain sweating risk — neither medication directly triggers perspiration in clinical evidence.
Should I choose between Mounjaro and Wegovy based on sweating risk?
Sweating is not a relevant factor in choosing between these medications, as neither commonly causes it. Your prescriber will consider BMI, weight-related health conditions, medical history, and other side effect tolerance when deciding which is suitable for you. A clinical assessment is required before prescription.
What should I do if I sweat whilst taking Mounjaro or Wegovy?
If you experience sweating, discuss it with your GP or prescriber. It is likely related to nausea or digestive discomfort rather than the medication itself. Do not stop taking your medication without medical guidance — your prescriber can advise on whether dose adjustment or alternative treatment is needed.
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