What it is
Tirzepatide is a dual receptor agonist: it activates the GIP and GLP-1 gut-hormone receptors at the same time, with no glucagon component. Mounjaro is centrally authorised, so a single EU authorisation covers all 27 member states, and it is the only tirzepatide brand authorised in the EU. It holds both a diabetes indication and a weight-management indication under the same name.Alongside the single-dose pre-filled pen, the Spanish register also lists
multi-dose KwikPen and vial presentations at every strength.
How it works
Both GIP and GLP-1 receptors are expressed in the hypothalamic arcuate nucleus and brainstem nuclei (area postrema and nucleus tractus solitarii), which together integrate energy-balance signals. Activating them reduces energy intake and appetite by increasing feelings of satiety and fullness, and by decreasing feelings of hunger. Tirzepatide also delays gastric emptying, so food leaves the stomach more slowly after a meal, increases insulin release in a glucose-dependent way, and lowers glucagon. The weight change comes mainly from eating less, and is mostly a loss of fat mass.Dual action
Acts on two gut-hormone receptors at once rather than one.
Reinforces satiety
Slows stomach emptying and helps regulate the insulin response.
Reviewed quarterly
A chronic treatment for as long as it is beneficial and safe.
What it’s authorised for
- Type 2 diabetes
- Weight management
Type 2 diabetes that is not sufficiently controlled in adults, alongside
diet and exercise — either on its own when metformin is inappropriate, or
combined with other diabetes medicines.
What the studies reported
The EMA marketing authorisation has been valid across the EU since 15 September 2022, under EMEA/H/C/005620. The pivotal trial, SURMOUNT-1, was a phase 3, randomised, double-blind, placebo-controlled trial (DOI 10.1056/NEJMoa2206038, PMID 35658024, ClinicalTrials.gov · NCT04184622). It enrolled 2,539 adults with a BMI of 30 kg/m² or more, or 27 kg/m² or more with at least one weight-related complication, and excluded anyone with diabetes. Participants were assigned 1:1:1:1 to once-weekly subcutaneous tirzepatide (5 mg, 10 mg, or 15 mg) or placebo for 72 weeks, including a 20-week dose-escalation period. The coprimary endpoints were the percentage change in weight from baseline and the proportion achieving 5% or more weight reduction, assessed using a treatment-regimen estimand in the intention-to-treat population. A readout is not the same as peer-reviewed publication — every NCT identifier here links to its ClinicalTrials.gov record. SURMOUNT-1 did not include an active comparator and was not designed to assess cardiovascular outcomes; the coprimary endpoints were weight-based only (PMID 35658024).Dose schedule
The starting dose is low, and increases are doctor-supervised and step-wise.1
Weeks 1–4 · 2.5 mg starting dose
This is the starting dose to help the body adjust. It is not increased
during this period.
2
From week 5 · Step up every 4 weeks as tolerated
The doctor may adjust the schedule based on how you are responding.
3
Month 4+ · Personalised maintenance dose
Building up to a maintenance dose between 2.5 and 15 mg a week, set by
the reviewing doctor.
4
Ongoing · Quarterly medical reviews
A loss of 5% or more of starting weight at 3 months is considered a good
response. The doctor reassesses every 3 months and decides, with you,
whether to continue, adjust or stop. Discontinuation is gradual and
paired with a maintenance plan.
Taking it day to day
- Pick one day each week and inject on the same day, at a time you can keep to.
- Store pens in the fridge (2–8°C) while unused. Once a pen is in use, keep it below 30°C for up to 30 days, and do not freeze it.
- Check the pen before use.
- Inject into the tummy, thigh or arm, just under the skin.
- Rotate the injection spot every week rather than using the same site repeatedly.
- Missed dose — the four-day rule: if a dose is missed, it can still be taken within 4 days. After 4 days, skip it and take the next dose on the regular scheduled day.
- Know how long a pen lasts before starting a new one.
What has been reported
Who it is not suitable for
Tirzepatide is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), because GLP-1 receptor agonists can promote C-cell proliferation in animal studies and the human relevance has not been ruled out. It is also contraindicated after a serious hypersensitivity reaction to tirzepatide or any of its excipients. A doctor rules Mounjaro out on any of these grounds, or where a listed authorised indication does not apply — the eligibility checks run on submission of your consultation, not afterwards.The full Mounjaro treatment guide — injection technique in more detail,
storage, and a day-by-day dose table — is published at
hi-doctor.ai/guides/mounjaro.
How Hi-Doctor handles it
A questionnaire covering BMI, medical history and current medication is reviewed by an EU-licensed doctor, who decides whether Mounjaro or another weight-loss option is appropriate. Cost of the medical consultation is set out on pricing; the medicine itself is paid separately at a pharmacy.Start a consultation
Weight-loss consultation
Answer the weight-loss questionnaire and a registered doctor reviews it.
They decide whether treatment is appropriate, which one, and at what dose —
and declining is a normal outcome. See what it costs
and how the review works.