Understanding the tirzepatide formulary and what it means for you

What 'formulary' actually means in this context

A formulary is a list of medicines that a health system has approved for prescribing within specific criteria. For tirzepatide, there are in practice two distinct formularies to think about: the NHS one, governed by NICE TA1026 and NHS England commissioning guidance, and the broader licensed indication, which sets the floor for private prescribing.

The NHS formulary position is deliberately phased. The first cohort to gain access, from June 2025, requires a BMI of 40 or above plus four or more of five qualifying conditions: high blood pressure, dyslipidaemia, obstructive sleep apnoea, cardiovascular disease, or type 2 diabetes. A second cohort, covering adults with a BMI of 35 to 39.9 plus four or more of those same conditions, was activated in June 2026. Further cohorts are expected to open around March 2027. BMI thresholds are reduced by 2.5 kg/m² for people from South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds.

The private prescribing floor is set by the medicine's UK licence, which is broader: adults with a BMI of 30 or above, or 27 or above alongside at least one weight-related condition such as prediabetes, hypertension, or raised cholesterol. A prescriber still assesses every case individually, the licence defines eligibility in principle, not automatic approval.

If you want to understand the full detail of what tirzepatide is and how it works, that sits separately from the formulary question addressed here.

Why the gap between NHS criteria and private criteria matters right now

You may be reading this because you've looked into NHS access and found you don't yet qualify, or because your GP's practice isn't participating in the new GP contract that allows primary care prescribing from April 2026. That gap is real, and it is worth acknowledging: it can feel frustrating to know a medicine exists, to know it has been recommended by NICE, and still to find the door is effectively closed for now.

The phased rollout exists because tirzepatide demand is high and NHS commissioning is cautious about capacity. It does not reflect a clinical judgement that the medicine is unsuitable for people in earlier cohorts, it reflects prioritisation by severity and condition burden.

For adults who sit within the private licensing criteria but outside the current NHS cohort, private prescribing through a registered online pharmacy is the lawful alternative. The key safeguard is identical in both settings: a prescriber reviews your full clinical picture before any supply. If you're weighing up cost as part of this decision, our Mounjaro price comparison guide sets out what private treatment typically costs and what legitimate pricing should include.

From a formulary perspective, the practical difference between NHS and private routes comes down to wait and criteria, not to the medicine itself, the same UK-licensed tirzepatide, the same starting dose, the same clinical framework.

What a prescriber considers beyond the headline BMI number

Whether you're pursuing the NHS route or a private one, a prescriber's assessment goes well beyond checking a BMI threshold. That number opens a door; it doesn't complete the clinical picture.

Relevant factors include existing conditions that may interact with treatment (a history of pancreatitis, certain gastrointestinal conditions, or medullary thyroid carcinoma would prompt a detailed clinical conversation), current medicines, and how your weight-related conditions are currently managed. Women using oral contraceptives should know that tirzepatide may reduce the pill's absorption during the first four weeks of treatment and for four weeks after each dose increase, so a non-oral method is advised during those windows, as noted in NHS England's guidance on weight-management injections.

The prescriber also considers context: are you transferring from another provider, and if so is there evidence of your current treatment and dose? Are you asking about a dose increase, and is there supporting weight-evidence? These aren't bureaucratic hurdles, they are the clinical steps that make treatment safe. You can read more about Mounjaro's UK licensing and clinical profile if you want the broader background before a consultation.

For a fuller picture of the science behind the molecule, including how it is structured and why the dual-agonist mechanism is distinct from earlier GLP-1 medicines, the tirzepatide formulation page covers that ground in detail, and our dedicated pages on the tirzepatide formula and the tirzepatide molecular formula go deeper into the chemistry for anyone who wants that level of detail.

Making the decision: NHS route, private route, or wait

There is no single right answer to which formulary route to take. Three scenarios are common.

If you meet the current NHS BMI and condition criteria, the first step is checking whether your GP practice is participating in the new GP contract. Not all practices are. If yours is not, a referral to a specialist weight management service remains an option, though waiting times vary considerably by area.

If you fall within the private licensed criteria but outside the NHS cohort, private prescribing gives you access now, with the same clinical oversight. The consultation is the same in principle: a prescriber reviews your health history, confirms suitability, and monitors your progress. At a regulated online pharmacy like nume, every repeat order is clinically re-reviewed rather than automatically renewed.

If you are unsure which category you fall into, that uncertainty is exactly what a free consultation resolves. A prescriber can tell you where you sit relative to both the NHS criteria and the licensed private threshold, and help you decide. Our weight-loss treatment overview gives the wider context if you want to read before speaking to anyone. When you're ready, speak to our prescribers through a free consultation, there's no obligation and no fee for the assessment itself.