The Wegovy pen: what to expect before your first injection

Is this the right moment to start, or are there things to settle first?

Most people searching for information about the Wegovy pen are somewhere between 'I think I want this' and 'I'm not sure I'm ready.' That is a reasonable place to be. The injection format puts some people off, even when the clinical case for treatment is clear. So before the mechanics, it is worth knowing: the Wegovy pen is a factory-assembled, pre-filled device. There is nothing to prepare, dilute, or draw up. You press it against the skin, press the button, and the pen handles the rest. The needle is covered before and after use, which removes the moment many people dread.

Clinically, Wegovy is licensed in the UK for adults with a BMI of 30 or above, or a BMI of 27 or above alongside a weight-related condition such as high blood pressure, high cholesterol, or type 2 diabetes. Lower thresholds apply for some ethnic backgrounds under UK guidance. A prescriber reviews the full picture (medical history, current medicines, and any contraindications) before recommending it. The full Wegovy overview covers the eligibility criteria in detail if you want to check those before going further.

One practical note: Wegovy is not available without a prescription in the UK. Any seller offering it otherwise is operating outside the law, and the MHRA has repeatedly warned about counterfeit weight-loss pens circulating online, some of which have contained the wrong substance entirely. Verifying the pharmacy through the GPhC register before ordering is the single most effective safety check you can do.

How the Wegovy pen actually works in practice

The pen contains semaglutide, which acts on GLP-1 receptors involved in appetite regulation and slowing gastric emptying. In practical terms, most people find that hunger signals become quieter and that feeling of fullness arrives sooner. The once-weekly injection is designed to maintain a steady level of the medicine, which is why the pen is always used on the same day each week where possible.

The injection sites are the abdomen, outer thigh, or upper arm. Rotating the site each week reduces the chance of localised skin reactions. A step-by-step walk-through of the injection technique itself, including how to hold the pen and what to do if you miss a dot of liquid before injecting, is covered in our guide to using the Wegovy pen. The guide to opening and preparing the pen handles the practical steps before the injection, including removing the cap correctly and checking the solution.

Needles on the pre-filled pen are single-use and should be disposed of safely after each injection. A sharps container is the correct disposal method, standard household bins are not suitable for used needles. Storage is in the fridge at 2–8°C; refer to the Patient Information Leaflet for the exact window if you need to keep it at room temperature temporarily, as that varies and the leaflet is the authoritative source.

The standard Wegovy injection pen schedule runs from 0.25 mg through 0.5, 1.0, 1.7, and up to 2.4 mg, with each step at roughly four-weekly intervals subject to tolerability. There is now also a 7.2 mg maintenance dose approved by the MHRA in April 2026. More on what the individual pen volumes mean in practice is at our page on Wegovy pen volumes in ml.

Side effects: what the evidence says and when to act

The most commonly reported side effects are gastrointestinal: nausea, loose stools, constipation, indigestion, and burping. For most people these are most noticeable after starting treatment or following a dose step, and they ease within a week or two as the body adjusts. Eating smaller portions and avoiding fatty or rich meals during the early weeks often helps.

The NHS's patient-level guidance on semaglutide lists the full side-effect profile and explains which symptoms warrant a call to a doctor. The signs that need prompt medical attention are severe, persistent stomach pain (particularly pain that radiates to the back) with or without vomiting, as this can indicate pancreatitis, an infrequent but serious risk highlighted in the MHRA's January 2026 Drug Safety Update for GLP-1 medicines. Gallbladder symptoms, signs of serious allergic reaction, and significant dehydration from prolonged vomiting or diarrhoea also need medical review without delay.

Wegovy is not recommended during pregnancy, while breastfeeding, or if you are actively trying to conceive. It is not licensed for anyone under 18. Women using oral contraceptives should be aware that GLP-1 medicines can affect absorption of other oral medicines, particularly during the early weeks; discuss this with your prescriber. The interaction profile for tirzepatide is more studied in this respect, but it is worth raising with any prescriber regardless of which medicine you are considering. Our comparison of weight-loss injection options covers the differences between the available treatments.

Getting a Wegovy pen through a regulated UK pharmacy

The only legal route to a Wegovy pen in the UK is through a valid prescription issued following a clinical assessment. A GPhC-registered online pharmacy, verified on the GPhC pharmacy register, can provide that consultation and, if appropriate, prescribe and dispense the treatment. That process covers medical history, current medicines, weight verification, and identity checks, it is a clinical review, not a formality.

Cost is a realistic factor in this decision. Wegovy pricing in the private market has risen since semaglutide supply stabilised, and the total cost of treatment varies by dose and provider. Our Wegovy cost and access page sets out what a legitimate private prescription includes and what to check before committing to any provider. The short version: a single transparent price that covers consultation, prescription, the medicine, and aftercare is a better benchmark than the lowest headline figure.

At nume, every consultation is personally reviewed by a GPhC-registered Independent Prescriber the same day. If treatment is clinically suitable and you order before noon on a working day, the pen is dispatched the same day and delivered by DPD the next working day, in plain unbranded packaging. If you would like to explore whether Wegovy is appropriate for you, starting a free consultation is the first step.