Prescription only
MounjaroTirzepatide · Dual GIP and GLP-1 receptor agonist
What is Mounjaro?
Mounjaro is the brand name for tirzepatide, a once-weekly injection licensed in the UK for weight management. It activates two gut hormone receptors, GIP and GLP-1, which together reduce appetite and slow how quickly the stomach empties. It is prescription-only and is used alongside a reduced-calorie diet and increased physical activity, not instead of them.
Licensed for weight management
Tirzepatide is authorised in the UK for weight management alongside a reduced-calorie diet and increased physical activity, and separately for type 2 diabetes. NICE has published guidance on its use for managing overweight and obesity (TA1026).
At a glance
- Active ingredient
- Tirzepatide
- Drug class
- Dual GIP and GLP-1 receptor agonist
- Administration
- Once-weekly subcutaneous injection
- Manufacturer
- Eli Lilly
- Dose range
- 2.5 mg – 15 mg weekly
Treatment options and pricing are discussed after clinical assessment, as required for prescription-only medicines.
Start your assessmentHow Mounjaro works
Tirzepatide mimics two naturally occurring gut hormones: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Most other treatments in this class act on GLP-1 alone.
Acting on these receptors slows gastric emptying, so food stays in the stomach longer and fullness lasts longer after a meal.
It also acts on appetite regulation in the brain, which reduces hunger and the frequency of food-seeking thoughts. The practical effect is that eating less feels achievable rather than effortful.
Because the effect is on appetite rather than on fat directly, results depend on the dietary and activity changes it makes easier to sustain.
Who it may suit
May be considered for
- Adults meeting the BMI thresholds set out in NICE guidance, assessed individually
- People whose weight is associated with conditions such as type 2 diabetes, hypertension or obstructive sleep apnoea
- People who can commit to dietary and activity changes alongside treatment
- People able to attend scheduled clinical reviews
Not suitable if
- Personal or family history of medullary thyroid carcinoma, or Multiple Endocrine Neoplasia syndrome type 2
- Pregnancy, breastfeeding, or planning to conceive within the next month
- Previous hypersensitivity to tirzepatide or any excipient
- History of pancreatitis, which requires individual clinical assessment
- Certain gastrointestinal conditions, assessed case by case
Dosage and titration
| Step | Dose | Timing |
|---|---|---|
| Starting dose | 2.5 mg | Once weekly for 4 weeks |
| First increase | 5 mg | After 4 weeks at 2.5 mg |
| Further increases | +2.5 mg | No sooner than every 4 weeks |
| Maximum dose | 15 mg | Once weekly |
The starting dose is not a treatment dose. It exists to let the body adjust and to limit gastrointestinal side effects. Increases are made only when the current dose is tolerated, and many people settle at a maintenance dose below the maximum. Dose decisions are made by your prescriber, never self-directed.
Side effects
Common Usually mild
- Nausea, most often in the days after a dose increase
- Diarrhoea or constipation
- Vomiting
- Indigestion and reduced appetite
- Injection-site reactions
- Fatigue
Serious Seek advice
- Pancreatitis, severe, persistent abdominal pain, which may radiate to the back
- Gallbladder problems, including gallstones
- Severe or persistent vomiting leading to dehydration
- Allergic reaction, swelling of the face, lips or throat, or difficulty breathing
- Low blood sugar, particularly when used with insulin or a sulfonylurea
In rodent studies tirzepatide caused dose-dependent thyroid C-cell tumours. Whether this occurs in humans is not known, which is why a personal or family history of medullary thyroid carcinoma is a contraindication. Seek urgent medical attention for severe abdominal pain or signs of an allergic reaction.
Interactions
- Oral contraceptives: tirzepatide can reduce their effectiveness because it delays gastric emptying. The effect is largest after the first dose. Switch to a non-oral method, or add a barrier method, for 4 weeks after starting and for 4 weeks after every dose increase.
- Other oral medicines: delayed gastric emptying can alter how quickly they are absorbed. Tell your prescriber about everything you take, including over-the-counter medicines.
- Insulin and sulfonylureas: used together, the risk of low blood sugar increases and doses may need adjusting.
- Alcohol: can worsen nausea and affect blood sugar control.
Storage
Store in a refrigerator at 2–8°C in the original carton, protected from light. Do not freeze. Once removed from the fridge it may be kept below 30°C for up to 30 days, after which it must be discarded. Refer to the patient information leaflet supplied with your pen for the definitive storage instructions.
How to get Mounjaro, and what it costs
If you are looking for where to buy Mounjaro, the short answer is a registered pharmacy, and only after a prescriber has assessed you. Mounjaro is a prescription-only medicine. It cannot be bought over the counter, from a supplement retailer, or from any website that sells it without an assessment, those are not legitimate suppliers, and what arrives from them is of unverified identity and strength.
The route is the same wherever you obtain it legitimately: a clinical assessment, review by a named prescriber, and supply from a registered pharmacy only if treatment is judged appropriate for you. There is no lawful shortcut around that step, and a provider offering one is telling you something useful about itself.
Cost varies by provider, by dose and by market, and is discussed after assessment rather than advertised, prescription-only medicines cannot be promoted to the public with pricing. What you can establish before committing is whether a provider verifies your information properly, who the named prescriber is, and what follow-up is included.
- 01Complete a clinical assessment
Medical history, current medication, BMI and any weight-related conditions. Around five minutes.
- 02Independent verification
Weight-management medicines are classed as high-risk, so a prescriber must verify your information rather than rely on the form alone.
- 03Prescriber decision
A named clinician decides whether treatment is appropriate. Some assessments end without treatment.
- 04Supply and follow-up
Dispensed by a registered pharmacy, with scheduled reviews to manage dose changes and side effects.
Where to buy Mounjaro in the UK
There are three lawful routes. Through the NHS, where access is limited and criteria are tight. Through a registered online pharmacy that assesses you first. Or from a high street pharmacy against a private prescription written by a prescriber who has assessed you.
Every one of those routes has an assessment in front of it, and that is the part that distinguishes them from the alternative. Any site that will sell you Mounjaro without one is operating outside the law, whatever it says about itself, and there is no way to establish what is actually in the box that arrives.
You can check any UK pharmacy yourself before you buy. Registered pharmacies appear on the General Pharmaceutical Council register, and every registered online pharmacy displays the MHRA distance selling logo, which links back to the regulator entry. If the logo is a picture rather than a link, that tells you something.
How to get a Mounjaro prescription
You complete a clinical assessment covering medical history, current medication, height and weight, and any weight-related conditions. A prescriber reviews it independently and decides whether Mounjaro is appropriate for you.
Because weight-management medicines are classed as high-risk, the prescriber must verify what you have reported rather than take the form at face value. That usually means a photograph, a video call, or contact with your GP. A provider that skips verification is not following the rules the regulator has set.
The decision can be no. Some assessments end without a prescription, either because the criteria are not met or because something in your history makes the medicine unsuitable. That is the assessment working, not failing.
How to identify a licensed Mounjaro supplier
Four checks, and they take about two minutes between them. The pharmacy appears on the GPhC register. It names its superintendent pharmacist. It displays the MHRA distance selling logo as a working link. And it requires an assessment before it will supply anything.
The signals that should stop you are just as consistent: a price advertised openly on the page, no assessment, no named prescriber, payment by bank transfer or cryptocurrency, or stock offered when legitimate pharmacies are reporting shortage. Sellers on social media and marketplace sites are not licensed suppliers regardless of what their listing claims.
Falsified tirzepatide has been found in UK supply chains, and the MHRA has seized it. It is not a theoretical risk, and the packaging on a counterfeit is frequently better than people expect.
Can you buy Mounjaro online?
Only from a registered pharmacy, and only after a clinical assessment and a prescription. Searching "mounjaro buy online" returns plenty of sites willing to skip both; none of them is a lawful supplier, and what arrives from them cannot be verified for identity, strength or sterility.
A legitimate online pharmacy looks different in one specific way: it will not let you reach a checkout before a prescriber has decided. If you can add Mounjaro to a basket, you are not on a pharmacy site.
What Mounjaro reviews do and do not tell you
Searching "mounjaro reviews" mostly returns individual accounts, and those are worth reading for what treatment feels like week to week: nausea after a dose increase, appetite changes, what people found manageable.
What reviews cannot tell you is whether Mounjaro is appropriate for you. Response varies considerably between people, and a review is a sample of one with no information about the reader. The trial data on this page is the part that generalises; the reviews are the part that does not.
Mounjaro price in the UK, and why no price is shown here
Cost depends on your dose, and the dose escalates over the first months, so a single figure would be wrong for most people most of the time. It also varies by provider and by market.
The reason no price appears on this page is narrower than it looks: prescription-only medicines cannot be advertised to the public in the UK, and a published price is advertising. You are quoted after assessment, when the dose is known. A site showing you a price for Mounjaro before it has assessed you is telling you it does not follow that rule.
What you can compare before committing is what is included. Whether follow-up reviews are part of the price, whether dose increases cost more, whether there is a charge to speak to a prescriber, and what happens if you stop.
Clinical evidence
What the trials showed
Mean weight reduction of 20.9% at the 15 mg dose
Across 72 weeks in adults with obesity or overweight without type 2 diabetes. Doses were escalated from 2.5 mg every 4 weeks until participants reached their allocated maintenance dose at week 20. Published figures for this trial vary between roughly 21% and 22.5% depending on which statistical estimand is reported, the lower figure reflects the treatment-regimen analysis, which counts everyone regardless of whether they stayed on treatment, and is the more conservative of the two.
Greater weight reduction than semaglutide, head to head
The first direct comparison of the two treatments, published in the New England Journal of Medicine. Across 72 weeks in 751 adults, tirzepatide produced a 20.2% mean reduction against 13.7% for semaglutide, alongside greater improvements in blood pressure, HbA1c, triglycerides and HDL cholesterol.
Recommended for managing overweight and obesity
NICE guidance sets out the eligible population and a phased implementation approach within the NHS, prioritising defined cohorts.
Mounjaro questions, answered
Where can I get Mounjaro?
From a registered pharmacy, after a prescriber has assessed you. That means the NHS where you meet the criteria, a registered online pharmacy that assesses you first, or a high street pharmacy against a private prescription. You can confirm any UK pharmacy on the General Pharmaceutical Council register before you order, and registered online pharmacies carry the MHRA distance selling logo as a working link.
Can I order Mounjaro online safely?
Yes, from a pharmacy registered with the GPhC that assesses you before supplying. The check is whether an assessment happens at all: a site that lets you add Mounjaro to a basket and pay without one is not operating lawfully, and falsified tirzepatide has been found in UK supply chains. Look for the named superintendent pharmacist and the MHRA distance selling logo linking back to the regulator.
Where can I buy Mounjaro?
Only from a registered pharmacy, following a clinical assessment and a prescription from a named prescriber. Mounjaro cannot be bought over the counter or from any site that supplies it without assessing you first. Sellers offering it without a prescription are supplying an unlicensed medicine of unverified identity and strength.
How do I get Mounjaro?
Complete a clinical assessment covering your medical history, current medication and BMI. A named prescriber then verifies that information independently, a questionnaire alone is not sufficient for weight-management medicines, and decides whether treatment is appropriate. If it is, a registered pharmacy dispenses it with scheduled follow-up.
How much does Mounjaro cost?
Cost varies by provider, by dose and by market, and is discussed after clinical assessment rather than advertised, because prescription-only medicines cannot be promoted to the public with pricing. Before committing, you can still establish whether a provider verifies your information properly, who the named prescriber is, and whether follow-up is included.
What is Mounjaro?
Mounjaro is the brand name for tirzepatide, a once-weekly injection licensed in the UK for weight management. It activates the GIP and GLP-1 receptors, reducing appetite and slowing gastric emptying. It is a prescription-only medicine used alongside diet and activity changes.
How is Mounjaro different from Wegovy?
Mounjaro acts on two receptors, GIP and GLP-1, while Wegovy contains semaglutide and acts on GLP-1 alone. Both are once-weekly injections licensed for weight management in the UK. The dual mechanism is the principal pharmacological difference; which is appropriate for a given person is a clinical decision.
How long does Mounjaro take to work?
Appetite changes are often noticed within the first few weeks, but the starting dose of 2.5 mg is an adjustment dose rather than a treatment dose. Meaningful weight change is generally assessed over months, and trial data measured outcomes across 72 weeks.
Does Mounjaro affect the contraceptive pill?
Yes. Tirzepatide can reduce the effectiveness of oral contraceptives because it delays gastric emptying, and the effect is greatest after the first dose. Use a non-oral method, or add a barrier method, for 4 weeks after starting treatment and for 4 weeks after each dose increase.
What happens if I stop taking Mounjaro?
Appetite typically returns to its previous level once treatment stops, and weight regain is common without a maintenance plan. This is why treatment is provided alongside structured support rather than on its own, and why any decision to stop should be discussed with your prescriber.
Is Mounjaro the same as Zepbound?
Both contain the same active ingredient, tirzepatide, but they are different brand names used in different territories. Zepbound is the US brand; in the UK the licensed brand is Mounjaro. Zepbound is not available from UK pharmacies.
Can you buy Mounjaro UK, and where from?
From a GPhC-registered pharmacy, after a prescriber has assessed you. Searching "buy Mounjaro UK" also returns sites that will supply without an assessment; none of those is a lawful supplier, and what arrives cannot be verified for identity, strength or sterility.
Where to get Mounjaro if the NHS route is not open to you?
A registered online pharmacy that assesses you first, or a high street pharmacy against a private prescription from a prescriber who has assessed you. Both have the same step in front of them, and the question of where to get Mounjaro is really the question of who is taking responsibility for the decision.
What makes a Mounjaro online pharmacy UK listing genuine?
Four checks. It appears on the General Pharmaceutical Council register. It names its superintendent pharmacist. It displays the MHRA distance selling logo as a working link rather than a picture. And it will not let you reach a checkout before a prescriber has decided. Any Mounjaro online pharmacy UK result missing one of those is not what it claims.
What is the Mounjaro price UK, and why is none shown here?
Cost depends on your dose, and the dose escalates over the first months, so a single figure would be wrong for most people most of the time. No Mounjaro price UK figure appears on this page for a narrower reason: prescription-only medicines cannot be advertised to the public in the UK, and a published price is advertising. You are quoted after assessment, when the dose is known.
Can you get Mounjaro without prescription?
No. Mounjaro is a prescription-only medicine, and searching "Mounjaro without prescription" returns sellers operating outside the law rather than a shortcut nobody told you about. What arrives from them has unverified identity, strength and sterility; falsified pens have been found in UK supply chains and seized by the MHRA. There is no pharmacy, in any country, that may lawfully supply it without one.
Sources
- Tirzepatide for managing overweight and obesity (TA1026) · NICE
- Mounjaro, Summary of Product Characteristics · electronic medicines compendium
- Obesity, overview and treatment · NHS
- Tirzepatide for managing overweight and obesity, evidence review · NCBI Bookshelf
Awaiting sign-off by a named clinician.
Last updated
Related
- How to buy weight loss medication safely
- Wegovy (semaglutide)
- Compare treatments
- Check your eligibility
- Managing side effects
- Dosage and titration
Eligibility is decided by a clinician, not a questionnaire. Assessment is free and takes about five minutes.