Mounjaro stocks: what's actually happening with supply in the UK

What the official record shows about Mounjaro demand and supply

When NICE published its appraisal of tirzepatide (TA1026) in December 2024, it formalized what pharmacies were already experiencing: this is a medicine with a large eligible population and a manufacturing pipeline that took time to scale. The NICE recommendation for tirzepatide confirmed its use for adults with a BMI of 35 or above and at least one weight-related condition on the NHS, with private eligibility extending to BMI 30 or 27 with a qualifying condition. That breadth of eligibility, combined with strong trial results, drove a sustained surge in demand from the moment private prescriptions became possible.

Eli Lilly has publicly acknowledged the supply pressure and has been adding production capacity at its manufacturing sites. Reports from UK pharmacies through 2024 and into 2025 described patchy availability, particularly at the 10mg, 12.5mg and 15mg doses, while the 2.5mg starter dose remained more reliably stocked. This pattern matters: patients who begin treatment can find the early weeks relatively straightforward but then face a gap when the time comes to increase their dose. Understanding that risk upfront helps you plan with your prescriber rather than being caught off guard.

One misconception worth setting aside gently: some people assume that a stock shortage means the medicine is being withdrawn or restricted. It isn't. Supply pressures reflect production and demand, not any regulatory concern about the medicine's safety or licensing status.

How Mounjaro stock shortages affect patients already on treatment

Clinical guidance from NHS England is clear that patients should not change their dose, switch medicine or restart treatment without speaking to their prescriber first. If your usual pharmacy cannot fulfil a prescription at the dose you need, the right step is to contact your clinical team rather than attempt to source it elsewhere. The NHS England weight-management injections guidance explicitly covers this scenario and notes that switching between GLP-1 medicines mid-treatment should only happen under clinical supervision.

For patients who have found Mounjaro at a lower dose than their current prescription, some prescribers will advise continuing at that lower dose temporarily rather than pausing altogether, since restarting from scratch can mean re-experiencing early side effects like nausea. That call belongs to your prescriber, based on your specific history and how long the gap might be. At nume, our prescribers review each situation individually before any repeat is dispensed, if stock constraints affect an order, a clinician will be in touch directly. If you are trying to locate a dispensing pharmacy, our guide to finding Mounjaro stockists near you can help narrow down your options.

Attempting to source Mounjaro through unofficial channels when a pharmacy is out of stock carries real risk. The MHRA has seized large quantities of counterfeit tirzepatide pens from illicit sellers, including from an unlicensed manufacturing site in the UK. Fake pens look convincing and have caused harm. The only safe route is a GPhC-registered pharmacy dispensing against a valid prescription.

Does stockpiling solve the problem?

It is tempting, when supply feels uncertain, to want several months' worth in the fridge at once. Clinical guidance advises against this, for reasons that are partly practical and partly about patient safety. Mounjaro pens must be stored refrigerated at 2–8°C, and each pen contains four weekly doses; the storage requirements mean that holding excess stock at home creates logistical and safety risks if a refrigerator fails or if your clinical situation changes (for example, if you need to pause treatment for surgery or illness). Our page on whether you can stockpile Mounjaro covers the guidance in more detail.

There is also an equity dimension that Eli Lilly and UK regulators have both noted: hoarding at scale by any group reduces availability for patients who need each dose on schedule. Your prescriber can advise on the appropriate quantity to hold based on your circumstances, the answer is nearly always one pen at a time, ordered when you need it. Thinking about cost alongside supply? The Eli Lilly UK price increase context is worth reading, since the September 2025 list-price change affected how private pharmacies price Mounjaro across all doses.

What to do if your dose is out of stock right now

If you are an existing patient and your current dose is unavailable, speak to your prescriber before making any decision. Do not skip doses for several weeks without clinical input, and do not attempt to substitute a different medicine or a different dose without a formal review. Dose timing matters: the clinical schedule for tirzepatide is built around four-week steps, and unplanned gaps can affect how your body responds when you restart. If you want to make the most of your treatment while navigating supply uncertainty, our practical tips for getting the best results from Mounjaro are worth a read alongside the dose schedule information available on the tirzepatide overview page.

If you are new to Mounjaro and wondering whether current stock levels make it worth starting, the honest answer is that availability at starter doses has been more consistent, and the dose-escalation schedule gives several months before higher doses are needed, by which time supply conditions may have changed. A prescriber can only assess you for the medicine itself; what happens at the pharmacy level is a separate question, and one our team can advise on as part of your clinical review. If you would like to understand your options more broadly, the weight-loss treatments overview sets out what is currently licensed and available in the UK.

Ready to speak to a clinician? Start your free consultation and a GPhC-registered prescriber will review your details the same day.