What doctors actually do when prescribing weight loss injections

Why do these injections need a doctor's involvement at all?

There is a widely held assumption that weight loss injections are straightforward top-ups, like a vitamin shot. They are not. Mounjaro and Wegovy work on receptors that regulate appetite, blood sugar, and gastric emptying. That mechanism is effective precisely because it alters how your body functions, and that is exactly why the MHRA classifies them as prescription-only medicines under UK law.

A prescriber reviewing your case is looking at the whole picture: your current weight and BMI, any conditions you already have (type 2 diabetes, high blood pressure, sleep apnoea), the medicines you take now, and whether anything in your history makes these treatments unsuitable. For example, a personal or close family history of medullary thyroid carcinoma is a contraindication; so is pregnancy. People planning surgery also need to tell their anaesthetist they are on a GLP-1 medicine, because these treatments affect gastric emptying, something NHS England specifically flags in its guidance on weight management injections.

The assessment is not bureaucracy for its own sake. It is the thing that separates treatment from risk.

What does the prescribing process look like in practice?

Whether you see a GP or use a regulated online service, the clinical steps are essentially the same. You provide a full medical history, detail your current medications, and confirm your weight. Identity is verified. A prescriber reviews everything (not software) and either approves treatment, requests more information, or explains why this treatment is not right for you at this time.

At nume, that review is carried out the same day by a GPhC-registered Independent Prescriber. Live video weight verification and photo ID are part of every new patient assessment. That is not a box-ticking exercise; it is what responsible dispensing looks like. Transfer patients are asked to provide evidence of their current treatment and most recent dose.

Once approved, the treatment is dispatched the same day (for orders placed before 12pm, Monday to Friday) and delivered free by DPD the next working day, in plain unbranded packaging. If you have questions about what the process involves, the FAQs page covers the most common ones.

You can also read more about the steps involved in obtaining weight loss injections through a regulated UK pharmacy.

What side effects do doctors watch for during treatment?

The most common effects are gastrointestinal: nausea, loose stools, constipation, acid reflux, and burping. These tend to be most noticeable in the first week or two after starting or after a dose increase, and they usually settle. Starting at the lowest dose and moving up gradually is the main way prescribers manage this, which is why the titration schedule exists.

Less common but more urgent: severe stomach pain that spreads toward the back, with or without vomiting, can be a sign of acute pancreatitis. In January 2026, the MHRA issued a Drug Safety Update reminding patients and clinicians that pancreatitis, while infrequent, is a known and potentially serious side effect of GLP-1 medicines. If that happens, stop the injection and get medical help straight away, do not wait for a scheduled review.

Women using oral contraceptives should be aware that tirzepatide (Mounjaro) can reduce absorption of the pill during the first four weeks of treatment and for four weeks after each dose increase. Adding a non-oral contraceptive method during those windows is recommended. NHS guidance does not flag the same interaction for semaglutide (Wegovy), though prescribers weigh this case by case.

Any suspected side effect can be reported directly to the MHRA via the Yellow Card scheme. Legitimate prescribers actively encourage this; it is part of how medicine safety evidence grows over time. It is also worth reading what UK doctors have said about the risks of weight loss injections, particularly if you are weighing up whether treatment is right for you.

Can you get weight loss injections at a doctor near you, or is online the only option?

Both routes exist. Some GP practices, particularly from April 2026 under the new GP contract, can now prescribe tirzepatide directly, though participation varies by practice and area, and NHS eligibility thresholds are strict. Many people find their GP is not yet offering this, or that they do not meet the current NHS criteria (which are phased, with the broadest access still several years away for most BMI ranges).

Private options fill that gap. Finding a prescriber near you is one route, though regulated online pharmacies registered with the GPhC offer the same clinical rigour without geography as a constraint. You can verify any online pharmacy on the GPhC register, the registration number should be easy to find. If it is not displayed, that is worth noting.

On pricing: the cost of treatment varies between providers, and it is worth understanding what a quoted price actually includes, prescription fees, delivery, and clinical aftercare are sometimes added separately. nume's pricing is single and transparent, covering consultation, prescription, treatment, delivery, and 7-day aftercare. There are no subscriptions and no auto-renewals. If you want to understand your options, checking your eligibility is a straightforward next step with no obligation.