Wegovy

What is Wegovy?

Wegovy is Novo Nordisk's brand name for semaglutide specifically formulated and approved for chronic weight management in adults with obesity. Launched in the UK in September 2023, Wegovy represents a significant advancement in obesity treatment, offering the first GLP-1 receptor agonist specifically licensed for weight loss rather than diabetes management.

Unlike Ozempic, which contains the same active ingredient but at lower doses for type 2 diabetes, Wegovy is dosed at 2.4mg weekly specifically for weight reduction. The medication has demonstrated remarkable efficacy in clinical trials, with participants achieving substantial and sustained weight loss when combined with lifestyle modifications.

Wegovy Dosage Schedule

Wegovy follows a carefully structured titration schedule designed to minimise side effects whilst building therapeutic efficacy. The dosing progression spans 20 weeks before reaching the maintenance dose:

• Weeks 1-4: 0.25mg (250 mcg) once weekly
• Weeks 5-8: 0.5mg (500 mcg) once weekly
• Weeks 9-12: 1mg (1000 mcg) once weekly
• Weeks 13-16: 1.7mg (1700 mcg) once weekly
• Week 17 onwards: 2.4mg (2400 mcg) maintenance dose

This gradual dose escalation allows the body to adapt to the medication's effects on gastric emptying and appetite regulation. Healthcare providers may adjust the timeline if patients experience persistent gastrointestinal side effects. The cost calculator can help estimate treatment expenses across the full titration period.

How Wegovy Works

Wegovy's active ingredient, semaglutide, mimics the naturally occurring hormone GLP-1 (glucagon-like peptide-1). This hormone regulates blood glucose levels and significantly impacts satiety and food intake. By activating GLP-1 receptors in the brain's appetite control centres, Wegovy reduces hunger signals and increases feelings of fullness after eating.

The medication also slows gastric emptying, meaning food remains in the stomach longer, contributing to prolonged satiety. These mechanisms work synergistically to reduce overall caloric intake whilst patients maintain their nutritional requirements.

Clinical Evidence and Weight Loss Results

The STEP (Semaglutide Treatment Effect in People with obesity) clinical trial programme provides comprehensive evidence for Wegovy's efficacy. The pivotal STEP 1 trial demonstrated that participants achieved an average weight reduction of 14.9% over 68 weeks when combining Wegovy with lifestyle interventions.

The STEP 4 trial specifically examined weight maintenance, showing that individuals who continued Wegovy treatment maintained their weight loss, whilst those switched to placebo regained significant weight. This evidence supports Wegovy's role as a long-term weight management solution rather than a short-term intervention.

Comparative analysis with Mounjaro (tirzepatide) suggests both medications offer substantial weight loss benefits, though direct head-to-head trials remain limited. Our comparison tool helps evaluate these treatment options.

Wegovy Side Effects

Gastrointestinal effects represent the most common adverse reactions with Wegovy treatment. These typically include nausea, diarrhoea, vomiting, constipation, and abdominal pain. The structured dosing schedule helps minimise these effects, with most patients experiencing reduced symptoms as treatment progresses.

Injection site reactions may occur, including redness, swelling, or itching at the injection location. These reactions are generally mild and resolve without intervention. More serious but rare side effects include pancreatitis, gallbladder problems, and potential thyroid concerns.

Patients should be aware of signs requiring immediate medical attention, including severe abdominal pain, persistent vomiting, or symptoms of allergic reactions. Understanding proper storage and injection techniques can help minimise adverse effects.

NHS Availability and Private Prescription

NICE has approved Wegovy for NHS prescription under specific criteria. Patients must have a BMI of 35 or above with at least one weight-related health condition, or a BMI between 30-34.9 in certain circumstances. Access typically requires referral to specialist weight management services.

The NHS rollout has been phased, with not all areas offering immediate access. Primary care prescribing is expected to expand gradually between 2024-2026. Private prescription options include established providers like Superdrug Health, Boots Online Doctor, and various specialist weight management clinics.

Understanding UK peptide legality helps patients navigate the regulatory landscape for weight management medications.

Wegovy's mechanism centres on its action as a GLP-1 receptor agonist, precisely mimicking the endogenous incretin hormone glucagon-like peptide-1. The medication binds with high affinity to GLP-1 receptors distributed throughout the body, particularly in pancreatic beta cells, the gastrointestinal tract, and crucially, in areas of the central nervous system involved in appetite regulation.

At the molecular level, semaglutide's structure includes modifications that extend its half-life compared to native GLP-1. A fatty acid side chain enables albumin binding, whilst amino acid substitutions at positions 8 and 34 provide resistance to DPP-4 degradation. These structural modifications allow for once-weekly dosing whilst maintaining therapeutic activity.

The primary weight loss mechanism occurs through GLP-1 receptor activation in the hypothalamus and brainstem, regions controlling satiety and food intake. This activation triggers cascades that reduce appetite signals whilst enhancing post-meal satiety. Simultaneously, Wegovy slows gastric emptying by relaxing gastric smooth muscle, prolonging the sensation of fullness after eating.

Peripheral effects contribute to the overall metabolic impact. GLP-1 receptor activation in pancreatic beta cells enhances glucose-dependent insulin secretion, whilst suppressing glucagon release from alpha cells. These actions help normalise blood glucose levels, though the weight loss effects appear independent of glycaemic improvements in non-diabetic patients.