Wegovy (Semaglutide) for Weight Loss: A Complete UK Guide

What is Wegovy?

Wegovy is the brand name for semaglutide 2.4 mg, a once-weekly subcutaneous injection licensed by the MHRA for chronic weight management in adults. It is manufactured by Novo Nordisk and was approved in the UK in 2021. Semaglutide is also available at lower doses under the brand name Ozempic for the management of type 2 diabetes — Wegovy is a higher-dose formulation specifically developed and licensed for weight management.

How does semaglutide work?

Semaglutide is a GLP-1 receptor agonist. GLP-1 (glucagon-like peptide-1) is a hormone produced in the gut after eating that signals fullness to the brain, slows the rate at which the stomach empties, and reduces appetite. Semaglutide mimics this hormone but with a much longer duration of action — allowing once-weekly dosing rather than the multiple daily injections required by earlier GLP-1 medicines.

The net effect is a significant and sustained reduction in appetite and calorie intake, leading to meaningful weight loss over time.

What does the evidence show?

The STEP clinical trial programme provides robust evidence for semaglutide 2.4 mg in weight management:

• STEP 1 — In adults with obesity or overweight without diabetes, participants achieved an average weight loss of 14.9% of body weight over 68 weeks, compared with 2.4% in the placebo group. Over 86% of participants achieved at least 5% weight loss.
• STEP 2 — In adults with type 2 diabetes, average weight loss was 9.6% — significantly greater than placebo and greater than most other approved treatments for this population.
• STEP 4 — Participants who continued semaglutide after an initial 20-week run-in maintained their weight loss, while those switched to placebo regained approximately two-thirds of the weight lost — confirming that ongoing treatment is needed to maintain results.
• SELECT trial — In adults with established cardiovascular disease and obesity, semaglutide reduced the risk of major cardiovascular events (heart attack, stroke, cardiovascular death) by 20% compared with placebo — the first weight management medicine to demonstrate cardiovascular benefit in a large randomised trial.

Dose escalation schedule

Wegovy is started at 0.25 mg once weekly and increased gradually over 16 weeks to the maintenance dose of 2.4 mg. The escalation schedule is: 0.25 mg (weeks 1 to 4), 0.5 mg (weeks 5 to 8), 1 mg (weeks 9 to 12), 1.7 mg (weeks 13 to 16), then 2.4 mg from week 17 onwards. This gradual increase is designed to minimise gastrointestinal side effects.

What are the common side effects?

Gastrointestinal side effects — nausea, vomiting, diarrhoea, constipation, and abdominal discomfort — are the most common and are most pronounced during dose escalation. They typically improve as the body adjusts. Eating smaller meals, avoiding high-fat foods, and staying well hydrated can help manage these effects. Serious side effects are uncommon and include pancreatitis and gallbladder disease.

Wegovy tablets: oral semaglutide

An oral formulation of semaglutide (Wegovy tablets) is also now available in the UK, offering the same active ingredient in tablet form for patients who prefer not to inject. The dose escalation schedule differs from the injection, and the tablets must be taken on an empty stomach with a small amount of water.

Book a consultation with Weight Loss Wales to find out whether semaglutide is right for you.