Can My Doctor Give Me Weight Loss Injections?

What the official UK guidance established about prescribing weight loss injections

NICE's appraisal of tirzepatide, published in December 2024 and updated in September 2025, recommended it for adults with a BMI of 35 or above alongside at least one weight-related health condition — for example, high blood pressure, type 2 diabetes, obstructive sleep apnoea, dyslipidaemia, or cardiovascular disease. Lower BMI thresholds apply for people from some ethnic backgrounds under UK guidance. From April 2026, GP practices can prescribe tirzepatide under the updated QOF contract, so in principle your own GP practice could initiate treatment. Whether they do depends on whether the practice has opted in and what local commissioning arrangements look like: availability genuinely does vary.

Wegovy (semaglutide) has its own NICE recommendation, published in 2023, but the NHS pathway sits within specialist weight management services for a maximum of two years. For most people, that means longer waiting times before a GP can refer and a specialist can prescribe. Your GP can still support the process and refer you, but they are not typically the prescriber in that pathway. The question of what your GP specifically can do depends on which medicine and which route is on the table.

Trial data sitting behind these recommendations is substantial. In SURMOUNT-1, involving 2,539 adults with obesity, participants taking tirzepatide at the highest dose lost an average of around 20–21% of their body weight over 72 weeks, as published in the New England Journal of Medicine. For semaglutide, the STEP 1 trial reported an average loss of around 15% over 68 weeks. These are population averages from controlled trials, and individual results vary.

What a prescriber actually assesses before saying yes

Eligibility for a weight loss injection is not decided by a single number on a scale. A prescriber works through several questions: your BMI, any existing conditions, your medication history, contraindications (including pregnancy, breastfeeding, or a history of certain conditions such as medullary thyroid carcinoma), and whether you are willing to make the accompanying dietary and activity changes the licence requires.

For tirzepatide, the private eligibility threshold set in the SmPC is a BMI of 30 or above, or 27 or above if you have at least one weight-related condition. So the bar for a private prescription is lower than the NHS commissioning threshold; what stays the same is the need for a proper clinical review. No legitimate prescriber skips this step. If you want to understand exactly what a doctor looks at before agreeing to prescribe, that goes into more detail.

There is a quick check worth doing right now if you are considering an online pharmacy: look the service up on the GPhC pharmacy register. It takes under a minute. If they are not listed, they cannot legally dispense prescription medicines in the UK. That one check filters out a significant number of unsafe sellers.

How the prescription route works in practice, NHS versus private

On the NHS, the first step is usually your GP. They can assess whether you meet the criteria for the relevant NICE-approved medicine, refer you if needed, and (for tirzepatide in practices that have opted in) potentially prescribe directly. Waiting times for NHS weight management services can be lengthy in many areas, and meeting the clinical criteria does not guarantee a short wait. The NHS approach also typically involves a structured programme of dietary and lifestyle support alongside the medicine, which is genuinely valuable and forms part of the licence conditions.

Private prescribers and GPhC-registered online pharmacies offer a parallel route, and if you are exploring that option it is worth reading about how doctor-led weight loss injection services work, including what the clinical assessment involves and what to look for in a provider. The advantage is speed and access, not a lower clinical bar. If you want to understand the wider landscape of weight loss injections available in the UK, that covers both medicines and how they compare.

Cost is a genuine consideration on the private route. Eli Lilly raised Mounjaro's UK list price from September 2025, and typical private prices since then have ranged roughly £149–£375 per month depending on dose and provider. If the price is a significant factor, the context around what drives the cost is worth reading before you compare providers on price alone. A headline figure that looks low often excludes the consultation, the prescription fee, or aftercare.

What to expect once a prescription is issued

Both Mounjaro and Wegovy are self-administered subcutaneous injections, given once weekly. Mounjaro comes as a pre-filled KwikPen containing four doses; treatment begins at 2.5mg, a starting level chosen to help your body adjust rather than to produce immediate weight loss, and the prescriber titrates upward from there in steps. Wegovy follows a similar escalation, from 0.25mg up to the maintenance dose, with newer 7.2mg pens now also MHRA-approved.

Most people administer the injection themselves at home. The technique for self-administering weight loss injections is straightforward once shown, and the Patient Information Leaflet that comes with your medicine walks through it step by step. Common side effects are mostly gastrointestinal: nausea, loose stools, constipation, or indigestion are all reported, particularly after starting or after a dose increase, and typically settle within a couple of weeks. The NHS tirzepatide page offers a thorough plain-language summary of what to watch for, including the side effects and when to seek medical help.

Ongoing clinical oversight matters throughout, not just at the start. Whether you are on an NHS programme or a private prescription, a prescriber should be reviewing your progress, not just issuing repeat supplies. At nume, every repeat order goes back to a prescriber for review. If you have further questions or want to talk through whether treatment might suit you, our clinical team is reachable through the contact page. When you are ready to take the next step, you can speak to our prescribers through a free consultation, reviewed the same day.