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
Does Mounjaro Make You Feel Cold?
Feeling unusually cold is not listed as a common side effect of Mounjaro (tirzepatide) in clinical trials or the UK product information. However, some people taking GLP-1 and GIP receptor agonists report feeling colder than usual. This may relate to reduced appetite, changes in metabolism, or weight loss itself rather than a direct effect of the medication. If you're experiencing persistent cold sensations while taking Mounjaro, it's important to discuss this with your GP to rule out other causes.
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.
Why Mounjaro Users Might Feel Cold
Feeling cold while taking Mounjaro isn't typically reported as a direct side effect of tirzepatide itself. However, several factors related to taking the medication may contribute to feeling colder:
- Reduced calorie intake: Lower appetite means fewer calories consumed, which can lower body temperature regulation
- Weight loss: Losing weight reduces body insulation, particularly if fat loss happens quickly
- Metabolic changes: GIP and GLP-1 receptor agonists affect how your body uses energy and glucose
- Nausea or reduced eating: Feeling sick may lead to eating less, affecting thermoregulation
- Individual metabolism: Some people naturally run cooler, especially during weight loss phases
These factors are distinct from allergic reactions or dangerous temperature regulation problems, which are rare. If you're concerned about persistent cold sensations, your GP can assess whether other conditions are involved.
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.
When to Speak to Your GP
Contact your GP if you experience:
- Severe, uncontrollable shivering or chills lasting hours
- Cold sensations alongside confusion, slurred speech, or difficulty concentrating (possible signs of hypothermia)
- Cold feelings combined with persistent nausea, vomiting, or inability to eat
- Unusual fatigue or weakness alongside feeling cold
- Cold symptoms that worsen over days rather than improving
In most cases, feeling slightly colder during Mounjaro treatment settles as your body adjusts. Wearing warmer clothing, staying hydrated, and eating regular balanced meals (within your calorie goals) may help. However, your prescriber needs to know about any side effects you experience, as they can assess whether they're related to Mounjaro or require investigation.
- 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 feeling cold a known side effect of Mounjaro?
Feeling cold is not listed as a common or very common side effect in Mounjaro clinical trials or UK product information. However, it may occur indirectly due to reduced appetite, weight loss, or lower calorie intake. If you experience persistent cold sensations, mention this to your GP.
Could feeling cold be a sign Mounjaro isn't working?
No. Feeling cold is not related to how well Mounjaro is working for weight management. The medication's effectiveness is measured by weight loss and metabolic improvements, not by temperature sensitivity. Cold feelings are more likely due to reduced eating or weight loss itself.
How is Mounjaro different from Wegovy if I'm considering both?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Both are prescription-only weight management injections licensed in the UK. Clinical trials showed Mounjaro may produce slightly greater average weight loss (~20.9% at maximum dose vs ~14.9% for Wegovy). Individual results vary significantly, and either medication may cause similar indirect effects like feeling cold due to reduced eating.
What should I eat to stay warm while taking Mounjaro?
Focus on warm, nutrient-dense foods like soups, stews, and hot drinks (tea, water). Eat balanced meals with protein, healthy fats, and vegetables within your calorie goals. Regular, smaller meals may help maintain energy and body temperature better than skipping meals. Your GP or a registered dietitian can provide personalised nutrition advice.
When does feeling cold usually stop on Mounjaro?
For most people, feeling colder settles within the first few weeks as your body adjusts to lower appetite and weight loss. As your weight stabilises and eating patterns normalise, temperature sensitivity typically improves. If cold feelings persist beyond 4–6 weeks or worsen, contact your GP to rule out other causes.
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.