Wegovy: What It Is, How It Works and Who It's For

Reviewed by: Dr Abdullah
Reading time: 7 minutes · Guidance verified: August 2026

Wegovy is one of the most searched-for weight-management treatments in Italy, and also one of the most misunderstood. It isn't a diet product, a supplement or a quick fix. It's a prescription-only medicine, licensed for specific patients, taken under clinical supervision. This guide sets out what it actually is, how it works in the body, who it's licensed for, what results the clinical trials show, and what to expect from side effects. Everything here reflects the authorised product information. It's for information only and doesn't replace advice from a prescriber who knows your medical history.

Key facts at a glance

Active ingredient: semaglutide
How it's taken: once-weekly injection under the skin
Maintenance dose: 2.4 mg weekly
Licensed for: adults with BMI ≥ 30, or BMI 27 to 30 with a weight-related condition; adolescents 12+ with obesity
Status in Italy: prescription-only (ricetta ripetibile, RR), Class C, not reimbursed by the SSN for weight management

What is Wegovy?

Wegovy is the brand name for semaglutide, a GLP-1 receptor agonist given as a once-weekly injection under the skin. Semaglutide is an analogue of GLP-1, a hormone your gut naturally releases after eating, sharing 94% of its structure. Because it's modified to last far longer in the body, with a half-life of around one week, a single weekly injection is enough.

It's licensed as an addition to a reduced-calorie diet and increased physical activity, never as a standalone treatment. That framing matters: in every trial behind its approval, participants also changed how they ate and moved.

How Wegovy works

GLP-1 is a physiological regulator of appetite and calorie intake, and its receptors sit in several areas of the brain involved in appetite control. Wegovy activates those receptors, producing effects most people notice within weeks:

Reduced hunger and stronger fullness. Clinical studies show it increases satiety and control over eating, while reducing hunger.
Lower calorie intake. In one study, calorie intake at a free-choice meal was 35% lower than with placebo.
Changed food preferences. It reduces the relative preference for high-fat foods.
Slower stomach emptying, contributing to feeling full for longer.

It also improves blood-sugar regulation in a glucose-dependent way, and body-composition sub-studies show the weight lost is predominantly fat mass, including visceral fat, rather than lean tissue. For the wider context on this class of medicines, see our guide to GLP-1 weight-loss injections.

Who Wegovy is licensed for

Wegovy is licensed for adults with a starting BMI of:

30 kg/m² or above (obesity), or
27 to under 30 kg/m² (overweight) with at least one weight-related condition, such as prediabetes or type 2 diabetes, high blood pressure, dyslipidaemia, obstructive sleep apnoea or cardiovascular disease.

It's also licensed for adolescents aged 12 and over with obesity and a body weight above 60 kg. In that group, treatment should be stopped and reassessed if BMI hasn't fallen by at least 5% after 12 weeks at the 2.4 mg dose.

Wegovy is not intended for cosmetic weight loss or for shedding a few kilograms. Obesity is treated here as a chronic medical condition, and eligibility is a clinical judgement, which is why a proper assessment comes first. At Medetone that starts with a weight-loss consultation.

How Wegovy is taken

The maintenance dose is 2.4 mg once weekly, reached gradually over 16 weeks to reduce gastrointestinal symptoms:

Weeks	Weekly dose
1 to 4	0.25 mg
5 to 8	0.5 mg
9 to 12	1 mg
13 to 16	1.7 mg
17 onward	2.4 mg (maintenance)

In adults with a starting BMI of 30 or above, the dose may be increased to 7.2 mg weekly after at least four weeks at 2.4 mg. If significant gastrointestinal symptoms occur, delaying the increase or returning to the previous dose is the recommended approach.

Practically: inject into the abdomen, thigh or upper arm, at any time of day, with or without food. The injection day can be changed provided at least 72 hours separate doses. If you miss a dose, take it as soon as possible within five days; if more than five days have passed, skip it and resume your normal schedule. Our Wegovy dosage guide covers titration in detail.

What results to expect

In the STEP 1 trial, covering 1,961 adults over 68 weeks, average weight loss was 14.9% compared with 2.4% on placebo. Within that group, 83.5% lost at least 5% of their body weight, 66.1% lost at least 10%, and 47.9% lost at least 15%. Waist circumference fell by 13.5 cm on average and systolic blood pressure by 6.2 mmHg.

Longer-term data from STEP 5 showed an average 15.2% reduction maintained at two years. And in the SELECT cardiovascular outcomes trial of 17,604 people with established cardiovascular disease and a BMI of 27 or above, semaglutide 2.4 mg reduced the relative risk of major adverse cardiovascular events by 20%.

These are averages, not promises. Response varies with dose reached, consistency and lifestyle changes. If you're comparing options, our Mounjaro vs Wegovy guide sets out the differences.

Side effects

Most side effects are gastrointestinal and concentrated in the dose-escalation period. Across trials, nausea affected 43.9% of patients, diarrhoea 29.7%, vomiting 24.5% and constipation 24.2%. Most episodes were mild to moderate and short-lived. Median duration was 8 days for nausea, 3 days for diarrhoea and 2 days for vomiting, though constipation lasted longer.

Common effects also include dizziness, indigestion, reflux, bloating, gallstones and hair loss. Uncommon effects include acute pancreatitis, raised heart rate and delayed gastric emptying. Serious allergic reactions are rare.

Seek prompt medical attention for severe persistent abdominal pain (possible pancreatitis), signs of gallbladder problems, sudden vision loss, or severe dehydration from ongoing vomiting or diarrhoea. Our Wegovy side effects guide covers management in full.

Who should not use Wegovy

Wegovy should not be used during pregnancy, and because of its long half-life it should be stopped at least two months before planning a pregnancy, or while breastfeeding. It's not recommended in severe kidney impairment, severe liver impairment, severe gastroparesis, type 1 diabetes, or NYHA class IV heart failure, and shouldn't be combined with another GLP-1 medicine. Caution applies with a history of pancreatitis or existing diabetic retinopathy. Tell your prescriber about all medicines you take. Our guide on medicines to be cautious with alongside Wegovy explains why.

Prescription status in Italy

In Italy, Wegovy is a prescription-only medicine (ricetta ripetibile, RR) authorised by AIFA, the Italian Medicines Agency. For weight management it is classified in Class C, meaning the cost is met by the patient rather than reimbursed by the SSN.

It should only be obtained through a legitimate route: a genuine clinical assessment followed by dispensing through a pharmacy authorised in Italy, never from marketplaces or sellers offering it without a prescription. Patients in the UK can access weight-management treatment through our partner service, Rightangled.

Frequently asked questions

How long does Wegovy take to work?

Appetite changes often appear within the first weeks, while meaningful weight change builds over months. Trials measured results at 68 weeks.

Do I have to take it forever?

It's a long-term treatment. Weight tends to return once it stops, so any decision to pause should be made with your prescriber.

Can I take Wegovy just to lose a few kilos?

No. It's licensed for specific BMI thresholds and clinical circumstances, not for cosmetic weight loss.

Does Wegovy have to be refrigerated?

Yes. Store between 2°C and 8°C, and don't freeze it.

In summary

Wegovy is a once-weekly semaglutide injection licensed for adults with BMI ≥ 30, or BMI 27 to 30 with a weight-related condition, and for adolescents from 12 with obesity. It acts on appetite regulation in the brain, producing average weight loss of around 15% in trials alongside diet and activity changes, with a 20% reduction in cardiovascular events in high-risk patients. It requires titration, monitoring, and above all a clinical assessment to confirm it's right for you.

Medical information: this article is for information only and does not replace diagnosis, prescription or medical advice. Wegovy is a prescription-only medicine. Always follow the instructions given by your prescriber.