Wegovy in the BNF: the British National Formulary entry explained

Step 1, understand what the BNF actually is (and is not)

The British National Formulary is a joint publication of the British Medical Association and the Royal Pharmaceutical Society, updated twice yearly and embedded in NHS clinical systems. It gives prescribers a concise, evidence-graded summary of every medicine licensed for use in the UK: indication, dose range, cautions, contra-indications, side effects and notable drug interactions. You can browse the BNF entry for semaglutide on the NICE BNF site.

What the BNF is not is a patient leaflet. It is written for clinicians and pharmacists, so the language is dense, the dose descriptions assume professional training, and the caution lists can look alarming without context. A patient reading a raw BNF entry may conclude a medicine is riskier, or simpler, than it really is. The SmPC and the Patient Information Leaflet are the documents written with patients in mind.

For Wegovy specifically, the BNF entry sits within the broader semaglutide BNF monograph, which covers all semaglutide products available in the UK. The entry separates indications clearly: weight management (Wegovy) and type 2 diabetes (Ozempic, Rybelsus). These are not interchangeable listings, and the BNF reflects that distinction precisely, a useful corrective for anyone who has seen semaglutide discussed loosely online.

Step 2, the BNF's record of Wegovy's licensed indication and monitoring requirements

The BNF records Wegovy's UK licence for weight management alongside a reduced-calorie diet and increased physical activity, for adults with a BMI of 30 or above, or a BMI of 27 or above alongside at least one weight-related condition such as high blood pressure, dyslipidaemia, type 2 diabetes or obstructive sleep apnoea. Lower BMI thresholds apply for certain ethnic backgrounds under UK guidance.

The Black Triangle symbol (▼) appears in the BNF entry. This marker, applied by the MHRA, signals that Wegovy is subject to additional monitoring. It does not mean the medicine is considered unsafe, it means regulators and manufacturers are actively collecting further real-world data beyond what clinical trials captured. Prescribers seeing the ▼ are expected to report any suspected adverse reactions via the Yellow Card scheme rather than treating unusual effects as insignificant. Patients can also report directly at yellowcard.mhra.gov.uk.

The BNF also cross-references NICE guidance. NICE's appraisal of semaglutide for weight management (TA875) recommends it within specialist weight management services, for a maximum of two years, and with multidisciplinary lifestyle support. The BNF reflects this framing, signalling to prescribers that Wegovy is not a standalone treatment but part of a structured programme. The broader Wegovy treatment guide on this site covers eligibility and the evidence base in plain English.

Step 3, side effects and interactions as the BNF records them

The BNF groups Wegovy's adverse effects by frequency: very common, common, uncommon and rare. The very common category includes nausea, vomiting, diarrhoea, constipation, abdominal pain and headache. These are consistent with what the NHS medicines page for semaglutide describes for patients: GI effects are most pronounced at the start of treatment or after a dose increase, and typically ease within a couple of weeks as the body adjusts.

The interaction section in the BNF draws attention to semaglutide's mechanism of slowing gastric emptying. This is not a minor footnote. Because food, drink and other medicines move through the stomach more slowly, the absorption of some orally-taken medicines can shift. The BNF specifically notes this in the context of oral contraceptives. Women taking the pill who are starting Wegovy should discuss this with their prescriber before the first dose. For a more detailed look at how Wegovy's titration schedule works in practice, the Wegovy 0.25mg starting dose page explains the first step, with subsequent increases moving through doses including Wegovy 0.5mg and on to the Wegovy 2mg maintenance dose.

The BNF also lists pancreatitis as a serious but infrequent risk. Prescribers are expected to counsel patients to seek urgent care for severe, persistent abdominal pain that may spread to the back, with or without vomiting. That guidance matters regardless of whether treatment was started via the NHS or a regulated private pharmacy.

How a private prescription relates to what the BNF sets out

Nothing in the BNF limits Wegovy to NHS prescribing. Any GPhC-registered Independent Prescriber working within their competence can prescribe it privately, provided the indication, clinical assessment and monitoring obligations described in the BNF and SmPC are met. What changes in private practice is the access route, not the clinical standards.

At nume, every consultation is personally reviewed by a GPhC-registered prescriber, your answers don't go through an automated filter and then get dispensed. A real clinician reads your submission. If you're clinically suitable and order before midday, your prescription is issued and your treatment dispatched that day, arriving the next working day in a plain DPD parcel with a tracking link so you know exactly when to expect it. The weight-loss treatment page explains what the process covers and what's included in the price.

For anyone reading a BNF entry and wondering whether their own circumstances fit, the most practical next step is a conversation with a prescriber, not more solo research. The BNF is a tool for clinicians; what it outlines is what any prescriber following it will work through with you. If you'd like to understand your options, check your eligibility with our clinical team.