Wegovy Weight Loss Injections: How They Work and What to Expect

Step 1: Preparing your injection — site, equipment and routine

Before you inject, gather what you need: the Wegovy pre-filled pen, a clean injection site, and an alcohol swab to clean the skin first. The three approved sites are your abdomen (avoiding the area immediately around the navel), the front of your thigh, or the outer upper arm. Rotate between them each week, using exactly the same spot repeatedly can cause localised skin changes over time.

Timing is flexible; most people pick the same day each week and attach it to an existing habit. The pen lives in the fridge door, which is a natural enough prompt. Remove it a few minutes before injecting so it is not ice-cold when it goes in, that alone reduces the sting for most people. You do not need to pinch the skin unless your prescriber has advised it.

Each Wegovy pen is pre-filled and pre-set to one dose. You click the button, hold it in place for the count your Patient Information Leaflet specifies, and you are done. The Wegovy pen locks after use; dispose of it promptly in a purpose-made sharps container rather than a household bin. The NHS advises pharmacies or local authority collection points for full containers.

If you miss a dose by more than five days, skip it and inject on your usual next scheduled day, never double up. Your prescriber and the Patient Information Leaflet are the right sources for timing questions; defer to them over anything you read elsewhere.

Step 2: How the dose schedule works in practice

Wegovy is not started at its full strength. The graduated schedule exists for good reason: beginning at a low dose gives your digestive system time to adjust, which substantially reduces early nausea. The standard licensed pathway runs 0.25mg for four weeks, then 0.5mg, then 1.0mg, then 1.7mg, reaching 2.4mg as the standard maintenance dose, each step roughly four weeks apart, paced by your prescriber based on how you are tolerating it.

Since January 2026 there has also been a 7.2mg dose, initially supplied as three concurrent 2.4mg pens weekly. On 14 April 2026 the MHRA approved a dedicated single-dose 7.2mg pen, making that the highest approved dose available in the UK; trials reported around 20.7% average weight loss over 72 weeks at this strength, approaching the results seen with tirzepatide at its highest dose. Whether the 7.2mg dose is appropriate is a clinical decision your prescriber makes, specific dose availability is confirmed at consultation, not assumed in advance.

Clinical trial evidence underpins the schedule. In the STEP 1 trial, published in the New England Journal of Medicine, adults using semaglutide 2.4mg alongside lifestyle changes achieved an average weight reduction of around 15% over 68 weeks. That is not a guarantee for any individual (biology, starting weight, diet quality and activity all interact) but it gives a realistic sense of what a full course can achieve. NICE recommends Wegovy for weight management under specific conditions, as set out in NICE technology appraisal TA875.

If you are interested in understanding how the costs of different treatments compare, the cost context for Wegovy in the UK sets out what a legitimate private price typically includes.

Step 3: Managing side effects through the dose steps

The most common side effects are gastrointestinal: nausea, loose stools, constipation, indigestion and burping. Fatigue and headache appear less frequently. For most people these are strongest in the first week or two of a new dose, then they settle. Small, plain meals, staying well hydrated and eating slowly all help. This is not a reason to stop; it is the system adjusting.

A small number of people experience more persistent or severe symptoms. The MHRA's January 2026 Drug Safety Update on GLP-1 medicines flagged acute pancreatitis as a known but infrequent risk: if you develop severe, persistent stomach pain that radiates through to your back, with or without vomiting, seek urgent medical attention. Do not wait and see. You can also report any suspected side effect directly at yellowcard.mhra.gov.uk.

Wegovy is not suitable during pregnancy, while breastfeeding, or if you are trying to conceive. It is not licensed for anyone under 18. People with a personal or family history of medullary thyroid carcinoma, MEN2, or a history of pancreatitis should discuss this with a prescriber before starting. These are not edge cases, they are part of the standard clinical assessment that any legitimate prescriber carries out.

For a broader overview of how semaglutide compares to other injection options, our semaglutide weight loss injections page covers the wider picture. Readers sometimes ask whether Ozempic is the same thing; the Ozempic and weight loss page explains the distinction, Ozempic is semaglutide licensed for type 2 diabetes, not weight management.

Step 4: What makes a Wegovy injection sourced through a regulated pharmacy different

Wegovy is a prescription-only medicine. The only legal route to it in the UK is a prescription following a clinical assessment, from a pharmacy registered with the GPhC. That assessment matters, not as a hoop to jump through, but because contraindications, interactions and medical history are genuinely relevant to whether the medicine is safe for you specifically.

A number of fake pens have appeared in the UK via social media sellers and unverified websites. The MHRA has seized large quantities of counterfeit weight-loss pens in recent years, some of which were found to contain insulin. Sellers offering these medicines without a valid prescription, at prices dramatically below market, or with discount codes attached are red flags. Check any online pharmacy on the GPhC pharmacy register before ordering; a GPhC-registered pharmacy's premises number is publicly verifiable there.

If you are considering starting Wegovy weight loss injections and want to understand whether you are a suitable candidate, speaking to our prescribers is the straightforward next step, consultation is free, reviewed the same day by a named GPhC-registered prescriber, and carries no obligation. If you would also like to explore where to access treatment locally, our page on semaglutide weight loss injections near me can help you find a regulated provider in your area.