Introduction

Wegovy (semaglutide) is a prescription-only GLP-1 weight-loss injection that has been clinically proven to support significant and sustained weight loss when combined with dietary and lifestyle changes. It works by mimicking the hormone GLP-1 (glucagon-like peptide-1), which plays a key role in appetite regulation, digestion, and blood-sugar control.

This guide explains how weight loss with Wegovy typically progresses over time, what results patients may expect at different stages, and which factors influence individual outcomes.


How Does Wegovy Support Weight Loss?

Wegovy works by activating GLP-1 receptors in the brain and digestive system. These effects help to:

  • Reduce appetite and food cravings

  • Increase feelings of fullness after meals

  • Slow gastric emptying

  • Improve blood-sugar control

Together, these mechanisms reduce overall calorie intake and support gradual, sustainable weight loss when used alongside a calorie-controlled diet and increased physical activity [1][2].

For a broader explanation of how GLP-1 weight-loss injections work and how Wegovy compares within this treatment class, see our GLP-1 weight loss injections complete guide.


How Wegovy Compares to Other Weight-Loss Injections

Wegovy (semaglutide) is a GLP-1 receptor agonist that supports weight loss by reducing appetite and slowing digestion. Other prescription weight-loss injections may act on additional hormone pathways and can lead to different average outcomes for some patients.

Clinical trials suggest that Mounjaro (tirzepatide), which activates both GLP-1 and GIP receptors, may lead to greater average weight loss than Wegovy for some patients, although individual results vary and suitability depends on medical history and tolerance. To see how results typically progress over time with Mounjaro (tirzepatide), view our Mounjaro weight-loss timeline and results guide.


Wegovy Weight-Loss Timeline: What to Expect

Weight loss with Wegovy is gradual and progressive. The dose is increased slowly over several weeks to help minimise side effects and allow the body to adjust.

Weeks 1–4: Starting Treatment

Patients typically begin Wegovy at a low dose. During this early phase, weight loss may be modest as the body adapts.

Common early changes include:

  • Reduced appetite

  • Feeling full sooner during meals

  • Mild gastrointestinal side effects such as nausea

Some patients notice early weight loss, while others primarily experience appetite changes before seeing measurable results [3].


Weeks 5–8: Appetite Suppression & Early Weight Loss

As the dose is increased, appetite suppression becomes more consistent for many patients.

Typical experiences during this stage include:

  • Reduced hunger between meals

  • Improved portion control

  • Gradual weekly weight loss

Clinical trial data shows that weight reduction often becomes more noticeable after the first month of treatment [3].


Weeks 9–12: Steady Progress

By this stage, many patients have reached a higher maintenance dose.

Common outcomes include:

  • Ongoing, steady weight loss

  • Improved blood-sugar control

  • Better energy levels as weight decreases

Studies demonstrate continued weight loss during this phase when Wegovy is combined with lifestyle changes [3][4].


3–6 Months: Clinically Meaningful Weight Loss

After several months of treatment, many patients achieve clinically meaningful weight loss, defined as a reduction that improves metabolic and cardiovascular health.

Reported benefits include:

  • Significant percentage reduction in body weight

  • Improvements in cholesterol and blood-sugar markers

  • Reduced obesity-related health risks

Longer treatment duration is associated with greater average weight loss [4].


12 Months and Beyond: Long-Term Results

Clinical trials show that patients who continue Wegovy long term may maintain or further improve their weight-loss results over time.

Discontinuing treatment can lead to weight regain, which is why ongoing medical supervision and lifestyle support are important [4].


Average Weight-Loss Results with Wegovy

In large clinical trials, patients using semaglutide 2.4 mg achieved significantly greater average weight loss than placebo.

Studies have reported:

  • Average weight loss of around 15% of body weight over 68 weeks

  • Greater weight reduction with continued treatment

  • Sustained results when lifestyle changes are maintained

These results represent clinical trial averages and may not reflect individual outcomes [3][4].


Factors That Influence Wegovy Results

Individual weight-loss outcomes can vary depending on:

  • Starting BMI

  • Dose and treatment duration

  • Diet and calorie intake

  • Physical activity levels

  • Adherence to treatment

  • Underlying metabolic conditions

Diet plays a major role in both weight-loss results and side-effect management. Our guide on what to eat while using weight loss injections explains how food choices can support appetite control, improve tolerance, and help maintain steady progress while using GLP-1 treatments.

Wegovy works best as part of a long-term weight-management plan, not as a standalone solution [2].


Important Safety Information

Wegovy is a prescription-only medicine and is not suitable for everyone. It must be prescribed following a medical assessment and used alongside dietary and lifestyle changes.

Common side effects include nausea, vomiting, diarrhoea, and constipation, particularly during dose increases. For a full breakdown of expected side effects, how long they typically last, and when to seek medical advice, see our weight-loss injection side effects explained guide.

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FAQs

How long does Wegovy take to start working?
Most people notice reduced appetite within the first few weeks of starting Wegovy. Visible weight loss may begin within the first month, but results vary depending on dose, lifestyle changes, and individual response.
How much weight can you lose on Wegovy?
Clinical trials show that patients using Wegovy (semaglutide 2.4 mg) lost an average of around 15% of their body weight over 68 weeks. Some people lose more, while others lose less depending on factors such as starting weight and adherence.
What does the Wegovy weight-loss timeline look like?
Weight loss with Wegovy is gradual. Early appetite reduction often occurs within weeks, with more noticeable weight loss typically seen after 1–2 months. Clinically meaningful weight loss is commonly achieved after 3–6 months of consistent treatment.
Why is Wegovy started at a low dose?
Wegovy doses are increased gradually to help reduce the risk of side effects, particularly nausea and gastrointestinal symptoms. This allows the body time to adjust before reaching the full maintenance dose.
Is weight loss faster on Wegovy or Mounjaro?
Clinical trials suggest that Mounjaro (tirzepatide) may lead to greater average weight loss than Wegovy. However, individual results vary, and suitability depends on medical history, tolerance, and prescriber assessment.
Can you regain weight after stopping Wegovy?
Yes. Studies show that stopping Wegovy can lead to weight regain, especially if lifestyle changes are not maintained. Wegovy is intended as part of a long-term weight-management plan.
Do you need to diet while taking Wegovy?
Yes. Wegovy works best when combined with a calorie-controlled diet and increased physical activity. The medication helps reduce appetite, making dietary changes easier to maintain.
What are the most common side effects of Wegovy?
Common side effects include nausea, vomiting, diarrhoea, constipation, and abdominal discomfort, particularly during dose increases. These effects are usually mild to moderate and often improve over time.
Is Wegovy suitable for everyone?
No. Wegovy is not suitable for people who are pregnant or breastfeeding, those with certain medical conditions, or individuals taking other GLP-1 medicines. A medical assessment is required before starting treatment.
How long do you need to stay on Wegovy to maintain results?
Many people need to continue Wegovy long term to maintain weight loss. Ongoing treatment, combined with lifestyle changes, helps support sustained results and reduce the risk of weight regain.

References

1. Wegovy (Semaglutide) – How It Works (GLP-1 Mechanism)

• Wegovy: how it works (GLP-1 appetite + slower digestion) – Diabetes UK

2. Clinical Guidance & Use Alongside Lifestyle Changes

• Semaglutide for managing overweight and obesity (technology appraisal) – NICE TA875
• Obesity treatment and management (diet, activity and treatment options) – NHS

3. Wegovy Weight-Loss Results (STEP-1 Trial – 68 Weeks)

• Once-weekly semaglutide in adults with overweight or obesity (STEP-1 primary publication) – New England Journal of Medicine

4. STEP-1 Supporting Record (Abstract/Index + Trial Registration)

• STEP-1 (Once-weekly semaglutide in adults with overweight or obesity) – PubMed
• STEP-1 Trial Registration (NCT03548935) – ClinicalTrials.gov

Medically Reviewed by Our GPhC-Registered Pharmacists

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Palvinder Deol

Authored by:

Palvinder Deol
Superintendent Pharmacist
Over 25 years’ clinical experience.
GPhC: 2047066
Nigel Howard

Reviewed by:

Nigel Howard
Independent Prescriber
Over 20 years’ clinical experience.
GPhC: 2047450

This article was medically reviewed for accuracy, safety, and alignment with UK clinical standards. Learn about our medical review process →

Content last updated: 17th December 2025 · Next review: January 2026

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