What amounts does Mounjaro come in — and how does the schedule work?

Why does Mounjaro start at such a low amount?

The 2.5 mg pen is genuinely not there to do heavy lifting on weight loss. Its job is to introduce tirzepatide to your system at a level most people tolerate well, the nausea and digestive discomfort that can accompany this class of medicine are typically at their most noticeable in the first couple of weeks on a new amount, and starting low blunts that considerably. Think of it as a calibration period.

Prescribers typically keep patients at 2.5 mg for around four weeks before considering whether moving up is appropriate. How that progression unfolds varies between individuals. Some people reach their therapeutic goal at 5 mg or 7.5 mg; others need to work through to the higher amounts before appetite suppression really settles into daily life. There is no fixed destination, the tirzepatide prescribing approach is to find the amount that produces good results while remaining manageable, which is a clinical conversation, not a formula.

The NHS tirzepatide medicines page confirms the six UK strengths and notes that dose increases happen gradually, on medical advice. That page is worth bookmarking if you have straightforward questions about the medicine itself.

What do the trial results actually say about different amounts?

Most of the trial data on Mounjaro's weight-loss effect comes from the SURMOUNT programme. In SURMOUNT-1, the pivotal trial that established tirzepatide's weight-loss profile, participants at the 15 mg amount lost around 20–21% of their body weight on average over 72 weeks, figures often described as among the largest seen in a licensed weight-loss medicine. The 10 mg amount produced roughly 19% average loss in the same trial, and the 5 mg amount around 15%. These are population averages from a controlled setting; real-world outcomes differ by person.

The broader SURMOUNT clinical programme enrolled thousands of adults across multiple studies, covering people with obesity and those with type 2 diabetes alongside excess weight. NICE reviewed this evidence base before recommending tirzepatide in its technology appraisal TA1026, published in December 2024.

One practical note: the largest effect sizes in the trials were seen at the highest amounts, but tolerability matters too. A prescriber who keeps you stable at 10 mg because 12.5 mg causes persistent nausea is making the right call, the amount that you can actually stay on is the one that works.

Can side effects change as the amount increases?

Yes, and this is one reason the stepped schedule exists. Gastrointestinal effects (nausea, loose stools, constipation, indigestion, bloating) are the most commonly reported, and they tend to flare briefly each time the amount goes up before settling down within days to a couple of weeks. Most people find the discomfort is manageable and temporary.

If you take a combined oral contraceptive pill, there is a specific point to know: the NHS England guidance on weight-management injections advises adding a non-oral contraceptive method during the first four weeks of treatment and for four weeks after each dose increase, because Mounjaro slows stomach emptying and may reduce absorption of the pill. It is worth discussing this with your prescriber before starting, and at every increase.

If you experience severe, persistent stomach pain that radiates toward your back, seek urgent medical help; this can be a sign of pancreatitis, a rare but serious side effect associated with this class of medicine. If you are also taking antibiotics, our guidance on using amoxicillin alongside Mounjaro covers what to be aware of during your course of treatment. Report any suspected side effects through the MHRA Yellow Card scheme.

Does the amount you use affect what Mounjaro costs privately?

In the UK private market, pricing does typically vary by strength. Eli Lilly raised the list price of its higher-dose Mounjaro pens significantly from September 2025, with the 15 mg pen's list price moving from around £122 to around £330, a change that rippled through private provider pricing across the market. For context on how those numbers translate into what patients pay, our breakdown of the Lilly UK price increase explains the background.

At nume, what you pay covers the consultation, prescription, the medicine, and free next-working-day delivery, one price, nothing added on separately. Current treatment pricing is shown on our treatment page. There are no subscriptions and no auto-renewals; every repeat order goes back to a prescriber for clinical review before anything ships. If you are weighing up whether to start or continue, timing sometimes matters practically, placing an order by 12pm Monday to Friday means same-day dispatch once your prescriber approves it, which can matter if you are planning around a holiday or a month's supply running low near a bank holiday weekend.

If you would like a prescriber to assess which amount is clinically appropriate for you, speak to our prescribers through a free consultation. The assessment covers your full medical picture, not just your BMI.