Mounjaro is considered safe, has been approved by the MHRA, and has undergone multiple clinical trials. However, it is still totally natural to have questions before starting a new treatment, especially about its safety.
Here, we'll cover everything you need to know about how safe Mounjaro is for weight loss, including practical tips for safe use, how healthcare providers monitor your wellbeing, and what the latest research from over 5,000 patients tells us about long-term safety.
Three Key Takeaways
Mounjaro is safe for most people when taken as prescribed with the support of a clinician.
Mounjaro has been approved by multiple regulatory agencies in the UK, like the MHRA, NICE and the NHS.
Mounjaro has undergone extensive clinical trials showing no long-term side effects so far. Most side effects usually go away on their own after 4-8 weeks.
How do we ensure Mounjaro's safety for you?
To ensure your safety on Mounjaro, we will always:
Ask you to complete a consultation
You must complete an online consultation when applying for any weight loss treatment at Chemist4U. This is where you tell us your medical history, from existing conditions to medications. This helps us understand your health so we can make sure it’s safe to prescribe treatment.
Ask you to submit photos
We request that you submit images of yourself for security purposes, but most importantly, for your safety. This is so our prescribers can verify who you are and check your weight, ensuring treatment is safe and suitable for you.
Make sure a clinician reviews your request
Your health is taken very seriously, which is why our UK-approved prescribers review every message and request that you submit. They’ll check if your current medications or health conditions interact with Mounjaro, and if they have any concerns, will discuss alternatives or suggest that you speak with your GP.
Our pharmacists are GPhC-regulated and licensed to prescribe Mounjaro and provide the necessary support and advice while you’re on it.
Clinical trials and safety data
If you’re worried about Mounjaro's safety, don’t just take our word for it—the data also reflects this.
SURPASS showed:
10-22% of patients experienced side effects
Only 5-8.5% of patients discontinued from the trial due to adverse effects
Remaining patients went on to lose up to 15% of their body weight
4-6% of patients discontinued from the trial due to adverse effects
20% weight loss for patients over 72 weeks who didn’t drop out
This is why, in 2024, the National Institute for Health and Care Excellence (NICE) authorised the use of tirzepatide (Mounjaro) to manage beingoverweight and obesity.
The NHS also approved prescribing Mounjaro to manage weight if you present with a BMI of 40 or higher, and at least four other weight-related health problems, including:
dyslipidaemia (abnormal fat levels in the blood)
hypertension (high blood pressure)
obstructive sleep apnoea (when your breathing stops and starts while you sleep)
cardiovascular disease (heart and blood vessel disease)
type 2 diabetes mellitus
The Medicines and Healthcare Products Regulatory Agency, more commonly known as the MHRA, constantly monitors the medication to ensure its safety.
Balancing safety vs effectiveness
To balance Mounjaro’s safety and effectiveness, it helps to look at the bigger picture. Some people experience mild side effects at first, like nausea, constipation, or diarrhoea, and around 10–15% stop treatment for this reason. For most, though, symptoms ease within 4–8 weeks, and those who stick with it usually find its smooth sailing, with many continuing successfully beyond three months.
On the benefits side, Mounjaro delivers an average weight loss of 22.5% over 72 weeks, while also improving cholesterol, lowering blood pressure, and reducing the risk of obesity-related cancers. When you weigh these lasting health gains against the short-term side effects, it’s clear why many people see Mounjaro as a worthwhile long-term investment in their health.
“When thinking about a new medication, it’s all too easy to worry about serious side effects, but in reality, these are extremely rare. Before any medication gets approved for use, it goes through years of rigorous testing to make sure it’s safe. Our clinicians always make sure your health is our top priority, and we monitor your treatment throughout. Try to focus on all the positive benefits of losing weight, and how much better your health will be in the long run, we’ll focus on making sure you’re safe.”
Ayesha Bashir, Prescribing Pharmacist
How safe is Mounjaro long-term?
Mounjaro is considered safe for long-term use. However, more studies will be carried out as it's a new medication.
While we don't yet have decades of data, the evidence we do have is reassuring, and ongoing monitoring helps make sure your continued well-being throughout treatment.
Studies following people for up to 2 years show that Mounjaro maintains a good safety profile with continued use. The most comprehensive data comes from the SURMOUNT trials, which tracked thousands of participants and found no long-term side effects.
Regulatory authorities monitor safety closely, and any new findings are quickly communicated to prescribers. That said, new data is consistently positive, with no unexpected safety concerns appearing as more people use these medications for extended periods.
Is Mounjaro safe for non-diabetics?
Yes, Mounjaro is safe to be used by those without diabetes. Mounjaro is widely prescribed for weight management in people without diabetes and has even been approved by the NHS for weight loss management.
Non-diabetics also don't face the risk of low blood sugar (hypoglycaemia) that diabetic patients might experience as a side effect.
Is Mounjaro safe for heart patients?
Mounjaro can often be used safely and may even offer cardiovascular benefits through weight loss.
Heart disease, high blood pressure and cardiovascular risks
For most people with stable heart disease or controlled high blood pressure, Mounjaro is generally safe, and the weight loss it promotes can improve cardiovascular health.
Studies show that losing weight can reduce strain on your heart, lower blood pressure, and improve cholesterol levels. However, if you have unstable angina, a recent heart attack (within the last 6 months), or severe heart failure, Mounjaro may not be suitable until your condition is stable.
Your prescriber will carefully review your current heart medications before starting Mounjaro, as weight loss may mean some medications need adjusting.
Considering alternatives
If you have cardiovascular disease, you might want to discuss switching to Wegovy as an alternative with your prescriber.
Wegovy has specific evidence, with the latest trials showing it can reduce major cardiovascular events in people with existing heart disease and obesity.
Your prescriber can help you weigh each option's benefits based on your heart health profile and treatment goals.
Is Mounjaro safe if you have other conditions?
Certain conditions can affect how Mounjaro works and may require extra care when prescribed. Here's what you need to know about common health conditions and Mounjaro.
Hypothyroidism and thyroid conditions
If you have a thyroid condition, you'll be pleased to know that Mounjaro doesn't interfere with how your thyroid works. However, Mounjaro slows down how quickly food moves through your stomach, affecting how well you absorb thyroid medications like levothyroxine.
This doesn't mean you can't take both. What it means is that your doctor might need to adjust when you take your thyroid medication or check your levels more frequently.
Always tell your prescriber about your thyroid conditions, even if they seem well-controlled.
High blood pressure
For most people with high blood pressure, Mounjaro is safe and may even help improve blood pressure through weight loss.
However, you should avoid Mounjaro if you have uncontrolled high blood pressure until it's properly managed.
Always inform your prescriber about all blood pressure medications you're taking.
Type-1 diabetes
Mounjaro is not currently licensed for type 1 diabetes and should not be used as a replacement for insulin.
While some specialists may occasionally consider it alongside insulin in specific circumstances, this would only be under strict specialist supervision with careful blood sugar monitoring.
If you have type 1 diabetes, discuss all weight management options with your diabetes specialist team first.
How to stay safe while using Mounjaro
Expert tips for safe use
Mounjaro is most effective when used correctly, and following a few key safety guidelines will help you get the best results while minimising any risks. These expert tips will support you throughout your treatment journey.
Always follow your titration schedule exactly as prescribed. The dosing schedule is designed to minimise side effects while achieving optimal therapeutic outcomes
Do not skip doses or change your injection frequency without medical advice, as this can affect how effective the treatment is and make you more likely to experience side effects
Monitor for side effects and report any concerns early to your healthcare provider
Red flags – when to see urgent help
Seek immediate medical attention if you experience:
severe nausea, vomiting, or abdominal pain that stops you from going about your day or keeping fluids down
signs of allergic reaction requiring emergency care include rash, itching, swelling of face/lips/tongue, difficulty breathing, or rapid pulse
sudden changes in mood, including depression or suicidal thoughts
vision changes such as blurring or loss of sight
Your safety is the most important. If you notice any of these symptoms, contact your healthcare provider immediately or go to A&E.
How to come off Mounjaro safely
Coming off Mounjaro safely should involve working with your prescribing pharmacist, who may suggest a step-down approach.
This means gradually reducing your dose to minimise side effects and prevent weight regain. You shouldn’t stop suddenly without speaking to your prescriber.
We understand that deciding to come off Mounjaro can feel daunting, especially if it's been working well for you. Your prescriber will help you prepare for any changes in appetite as your body adjusts.
Together, you'll also explore ways to maintain the positive changes you've achieved through sustainable lifestyle adjustments that work for you, such as diet and exercise.
Safe places to buy Mounjaro online
When buying Mounjaro online, your safety depends on choosing a properly licensed UK pharmacy.
It's easy to check; legitimate pharmacies display their GPhC (General Pharmaceutical Council) registration number on their website.
These pharmacies always require a consultation before prescribing, asking about your medical history, and providing genuine medication stored correctly.
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