Tirzepatide options: what's available in the UK and how the process works

Step 1, Understand what tirzepatide actually is before picking a route

Tirzepatide works on two gut-hormone receptors: GIP and GLP-1. That dual action slows gastric emptying, reduces appetite, and influences blood-sugar regulation in ways that a single-pathway medicine does not. It is the only weight-loss medicine in the UK with this mechanism, and that distinction matters when you are weighing up your options.

In the UK, tirzepatide is sold under the brand name Mounjaro, made by Eli Lilly. Each pre-filled KwikPen contains four weekly doses. You inject it once a week into your abdomen, thigh, or upper arm, rotating the site. The pen lives in the fridge (most people slot it in the fridge door, much like a small bottle of sauce) and you take it out a few minutes before use.

The SURMOUNT-1 trial, published in the New England Journal of Medicine, enrolled 2,539 adults with obesity and reported average body-weight reductions of around 20–21% at the 15 mg dose over 72 weeks. Those are the headline numbers. What they do not tell you is which dose you will end up on, that is a clinical conversation, not a product choice you make alone.

If you want a broader picture of how tirzepatide fits within GLP-1 medicines generally, that is a useful next read before going further.

Step 2, Work out which access route is realistic for you

There are two real options in the UK: NHS or private. NHS access to tirzepatide under NICE's appraisal TA1026 is currently phased. From around June 2025, the NHS began offering it to adults with a BMI of 40 or above who also have four or more specific conditions (high blood pressure, dyslipidaemia, obstructive sleep apnoea, cardiovascular disease, or type 2 diabetes). A second cohort (BMI 35 to 39.9 with four or more of those conditions) became eligible from June 2026. Thresholds are 2.5 kg/m² lower for some ethnic backgrounds. NHS treatment also requires participation in wraparound diet and activity support, and GP involvement is optional by practice, so availability varies considerably by area.

For people who do not meet those criteria, or who are not prepared to wait, a private prescription from a GPhC-registered online pharmacy is the alternative. There is no referral and no waiting list, but the clinical assessment is real regardless. A prescriber still reviews your health history, confirms your weight, checks your identity, and decides whether treatment is appropriate. The private route is faster, not a shortcut.

Anyone comparing Mounjaro and tirzepatide as terms will find they are the same medicine, the brand name and the molecule name for the same product.

Step 3, Know the strength options and what the titration schedule means in practice

Six pen strengths exist: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. Treatment starts at 2.5 mg, that dose exists to give your body four weeks to adjust before the dose rises. It is not expected to drive significant weight loss on its own. The prescriber then moves you up in roughly four-week steps, pausing at any rung if side effects need settling, until you reach the dose that works for you clinically.

Side effects are mostly gastrointestinal: nausea, loose stools, constipation, reflux, and occasional burping are the most common. They tend to be most noticeable in the days after starting or increasing, and most people find they ease within a week or two. Staying hydrated and keeping meals smaller helps a lot of people through the early weeks.

If you are curious about how lower doses compare in terms of effect, or whether the 15 mg ceiling is where most people end up, those details are worth exploring once you have a consultation in progress. What to take and when to change it are decisions your prescriber makes with you, not something a dose guide should prescribe from a distance.

For a look at the cost picture before booking anything, the context around Eli Lilly's 2025 UK price changes is relevant background.

Step 4, Starting with a regulated pharmacy: what the process looks like

At nume, the process is a straightforward sequence. You complete a free health consultation online. A GPhC-registered Independent Prescriber reads your answers (a real clinician, not an automated system) and reviews your suitability the same day. If approved, your identity and weight are verified before anything is dispensed. Order by midday Monday to Friday and, once clinically approved, treatment is dispatched the same day, arriving via tracked DPD the next working day in plain, unbranded packaging. No subscription is set up. Every repeat order goes through a fresh clinical review.

You can verify any online pharmacy on the GPhC's public register before you order, it is the fastest check you can do to confirm a pharmacy is legitimate. Our registration number is 9012878. Fake tirzepatide pens do circulate online; the MHRA has issued repeated warnings about counterfeit weight-loss injections sold without clinical oversight. A regulated supply chain matters for a medicine at this dose and duration.

Our clinical team and FAQs page have more detail on how the service is structured if you want to read further before starting. When you are ready, speak to our prescribers, the consultation is free and there is no obligation.