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Wegovy contains semaglutide and is given as one injection under the skin, once a week, on the same day each week. This page covers the handling of the pen. Your dose and your schedule come from the doctor who reviewed your consultation.
The patient information leaflet packed with your own pen, and the instructions your doctor gave you, override everything on this page. Pen designs, needle types and dose steps differ between products and between presentations of the same product. If the two disagree, follow the leaflet and your doctor, and message the medical team.

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What Wegovy is

Wegovy is a once-weekly injection for weight management. It copies GLP-1, a gut hormone that signals fullness to your brain and slows how quickly your stomach empties. The EMA marketing authorisation has been valid across the EU since 6 January 2022 under EMEA/H/C/005422, and one central authorisation covers all 27 member states. It is prescribed alongside changes to diet and activity, as part of a medically supervised plan.

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Mechanism at the receptor level

Semaglutide is a selective GLP-1 receptor agonist. At the 2.4 mg weekly dose used in Wegovy, receptor occupancy in the hypothalamic arcuate nucleus is sufficient to produce a sustained reduction in hunger signalling via POMC neuron activation and NPY/AgRP neuron inhibition. Peripherally, GLP-1 receptor activation slows gastric emptying and potentiates glucose-dependent insulin secretion. The 2.4 mg dose is approximately 2.4 times the maximum glucose-lowering dose (1.0 mg), which is why weight loss exceeds what is seen with Ozempic.

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Key trial design — STEP 1

The pivotal phase 3 trial (STEP 1, NCT03548935) was a double-blind, randomised, placebo-controlled study. 1,961 adults with a BMI of 30 kg/m² or greater (or 27 kg/m² with ≥1 weight-related complication) who did not have diabetes were assigned 2:1 to semaglutide 2.4 mg weekly or placebo for 68 weeks, both with lifestyle intervention. The co-primary endpoints were percent change in body weight and the proportion achieving ≥5% weight loss. The primary estimand assessed treatment effect regardless of discontinuation. Mean weight change was −14.9% with semaglutide versus −2.4% with placebo; 86.4% achieved ≥5% weight loss versus 31.5%. Gastrointestinal adverse events led to discontinuation in 4.5% of the semaglutide group versus 0.8% with placebo.

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Contraindications explained by mechanism

Contraindicated in personal or family history of MTC or MEN 2 (GLP-1 receptor-mediated C-cell proliferation risk, based on rodent studies). Also contraindicated in pregnancy. Semaglutide should not be used in type 1 diabetes. The reviewing doctor screens for severe gastroparesis or chronic severe gastrointestinal disease because GLP-1-mediated gastric slowing can worsen symptoms.

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Population specifics

No dose adjustment needed for mild-to-moderate renal impairment. Limited data in severe renal impairment (eGFR 15–29 mL/min/1.73 m²); not recommended in end-stage renal disease. No dose adjustment needed in mild-to-moderate hepatic impairment; not studied in severe hepatic impairment. Not recommended during pregnancy or breastfeeding.

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Injecting

The injection itself is a fixed sequence. Work through it in this order every week, and check each step against your own leaflet the first few times.
1

Wash your hands and check the pen

Look at the label and the expiry date. Check the liquid before injecting — if it does not look the way the leaflet describes, do not use that pen. Do not shake the pen.
2

Attach a new needle

Use a fresh needle every time. Needles are single-use.
3

Choose and rotate the injection site

Rotate between abdomen, thigh or upper arm each week. Clean the area with an alcohol swab and let it dry.
4

Inject just under the skin

Wegovy is injected subcutaneously. Do not inject into a vein or muscle. Pinching the skin gently can help at a site with little fat.
5

Hold the pen still until the dose is delivered

Your leaflet states how long to hold for your pen.
6

Remove the needle and dispose of it safely

Take the needle off after each injection and put it in a sharps container. Never reuse needles. See injection sites and sharps disposal.

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Pick a day and keep it

Inject on the same day each week. Pick a day that works for you. If you forget a dose, take it within 4 days of the missed dose. If more than 4 days have passed, skip that dose and take your next one on the regular scheduled day. More on this in missed or late doses.

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The published dose schedule

Semaglutide is dosed at 0.25 – 2.4 mg per week. The published escalation is:
This is the published ladder, not an instruction. The reviewing doctor decides your starting dose, whether you move up, and when. Ask in your account chat before changing anything.

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Storage

Store unused pens in the refrigerator (2–8°C). Once opened, keep at room temperature below 30°C for up to 30 days. Do not freeze. Keep away from direct heat and light.

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Contact your doctor if

  • severe or persistent nausea, vomiting or diarrhoea prevents you from eating or drinking
  • you have severe abdominal pain that does not go away
  • you notice signs of an allergic reaction — rash, itching, swelling of the face or throat
  • any symptom worries you or feels unusual
For severe, sudden or unexpected symptoms, call your local emergency number first — see Safety.

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Common questions

Wegovy is a once-weekly injection for weight management. It copies GLP-1, a gut hormone that signals fullness to your brain and slows how quickly your stomach empties. It is prescribed alongside changes to diet and activity, as part of a medically supervised plan.
Most patients notice reduced appetite within 2 to 4 weeks. Weight loss is assessed at 3 months. A loss of 5% or more of your starting weight is considered a good response. Your doctor monitors progress and adjusts the plan as needed.
Nausea is very common in the first weeks. Eat smaller meals, avoid fatty or fried foods, and eat slowly. Nausea usually improves within 1 to 2 weeks. Contact your doctor if severe or persistent nausea prevents you from eating or drinking.
If you forget a dose, take it within 4 days of the missed dose. If more than 4 days have passed, skip that dose and take your next one on the regular scheduled day. See the missed or late doses guide for more detail.
Moderate alcohol is not known to interact with semaglutide, but alcohol can worsen nausea and other gastrointestinal side effects. Follow your doctor’s advice and stay within sensible limits.
Related: Wegovy · semaglutide · side effects of weight-loss medicines

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Start a consultation

Weight-loss consultation

Answer the weight-loss questionnaire and a registered doctor reviews it. They decide whether treatment is appropriate, which one, and at what dose — and declining is a normal outcome. See what it costs and how the review works.
This page is reference information, not medical advice and not a prescription. Whether a medicine is appropriate for you is decided by a registered doctor after reviewing your consultation.