¿Cómo funciona Wegovy para la pérdida de peso?

What is Wegovy?

Wegovy is the brand name for a prescription weight loss medication containing semaglutide.

It belongs to a group of medicines called GLP-1 (Glucagon-like peptide 1) receptor agonists, which mimic one of the body’s natural gut hormones involved in appetite and blood sugar regulation.

Wegovy is taken as a once-weekly injection and works by reducing hunger, increasing feelings of fullness, and helping people naturally eat fewer calories.

Wegovy is licensed in the UK to support weight management in adults who:

• Have a body mass index (BMI) of 30 or above.

• Have a BMI of 27 or above alongside weight-related health conditions such as high blood pressure, sleep apnoea, raised cholesterol, or type 2 diabetes.

Dr Nienke Lees, Women's Health Service Lead at Genwell, explains: “Wegovy is not a magic wand, but for the right person it can be a really helpful tool. It has genuinely changed what we are able to offer some patients struggling with their weight.”

How does Wegovy work?

Wegovy works for weight loss by mimicking a natural hormone called GLP-1, which helps regulate appetite, fullness, digestion, and blood sugar.

It acts on areas of the brain involved in hunger and cravings, helping people feel fuller sooner, stay full longer, and think less about food.

It also slows stomach emptying and improves blood sugar regulation, which together can reduce calorie intake and support sustainable weight loss.

In practice, Wegovy helps with weight loss in five key ways:

1. It helps you feel less hungry

Many of us think hunger works like the fuel sensor in our cars; you are hungry because your body needs energy.

In reality, appetite is driven by two overlapping systems:

• Homeostatic hunger is biological hunger. It is impacted by stretch receptors in our stomachs, changes in levels of chemical signals (including GLP-1) and is based on our body trying to maintain energy balance and body weight.

• Hedonic hunger is reward-driven eating. This is the desire to eat because food is pleasurable, comforting, tempting, or sociable.

This helps explain why you might feel physically full after dinner yet still want dessert. Or why stress, tiredness or habit can make food feel hard to resist.

Wegovy appears to act on ambos of these pathways.

2. It helps reduce biological hunger

Wegovy acts on appetite centres in the brain, helping to reduce hunger signals and increase feelings of fullness.

3. It can reduce “food noise”

This describes the constant mental chatter around food that some of us hear more than others: What’s for lunch? Shall I have a snack? Maybe just one biscuit. What am I having tonight?

Not everyone experiences food noise in the same way, but many people taking Wegovy describe a noticeable reduction in how intrusive and all-consuming these thoughts can be.

This is because GLP-1 medications act on the mesolimbic reward system in the brain. This is the same system involved in habits, cravings and anticipation of reward.¹

That’s not to say that food is no longer enjoyable whilst using Wegovy. Many people simply describe feeling more in control around eating.

Lees adds: “For some people, the biggest change is not actually the weight loss. It’s feeling less preoccupied by food and no longer feeling like they are constantly battling themselves.”

4. It slows digestion

Wegovy also slows gastric emptying, meaning food leaves the stomach more slowly.

This can help people feel fuller for longer after meals and may reduce the urge to eat again quickly.

It is also one reason some people notice nausea, bloating, or feeling full more quickly when they first start treatment.

5. It affects blood sugar regulation

GLP-1 also plays an important role in blood sugar control, which is why many GLP-1 medications are also used to treat diabetes.

When blood glucose levels rise after eating, Wegovy helps the pancreas release insulin more effectively. At the same time, it reduces levels of another hormone called glucagon, which normally raises blood sugar.

So, although Wegovy is often described as an appetite suppressant, that is only part of the picture. It works across the gut, brain, and pancreas to help regulate eating, fullness, blood sugar, and weight.

How much weight can you lose on Wegovy?

Weight loss varies from person to person.

In one of the largest clinical trials, people taking Wegovy alongside lifestyle support lost an average of around 15% of their body weight over approximately 68 weeks. Some lost more and some less.²

Whilst some people lose weight quickly at first, others lose more gradually over many months. Generally, weight loss tends to be steady rather than rapid.

How long does Wegovy take to work?

Some people notice changes in appetite within days. Others notice more gradual changes over several weeks.

Wegovy is started at a low dose and increased slowly over time to reduce side effects and help the body adjust.

Because of this, the full effect is usually not immediate, with more noticeable weight changes often happening after 8-12 weeks.

How is Wegovy different to Mounjaro?

Wegovy and Mounjaro are both weekly weight loss injections that help reduce appetite and support weight loss, but they work slightly differently.

Wegovy contains semaglutide, which mimics one gut hormone: GLP-1. Mounjaro contains tirzepatida, which mimics two gut hormones: GLP-1 and GIP (Glucose-dependent insulinotropic peptide).

Because Mounjaro targets two hormonal pathways instead of one, studies suggest it may lead to greater average weight loss for some people, although individual responses vary.³

Neither medication is automatically “better”. The best choice depends on your health history, goals, side effects, availability, and cost.

Lees says: “We are still learning more about these medications all the time. What works brilliantly for one person may not suit another, which is why personalised care matters.”

How to get Wegovy

In the UK, Wegovy may be available through specialist NHS weight management services, although access varies by area and eligibility criteria can be strict.

It is also available for weight loss through private clinics and online providers, such as Genwell UK.

Wegovy is not suitable for everyone, and certain medical conditions, medications, pregnancy, or breastfeeding may affect whether it is appropriate.

Lees adds: “People deserve proper support whilst using Wegovy, not just a prescription. Knowing what to expect, how to manage side effects, how to protect muscle mass, and how to change your relationship with food can make a real difference.”

Resumen

Wegovy works for weight loss by mimicking a natural hormone called GLP-1, helping to reduce hunger, increase feelings of fullness, slow digestion, and regulate blood sugar.

Together, these effects can help people eat less naturally, reduce cravings and feel less preoccupied by food.

For some people, this creates the breathing space needed to build healthier, more sustainable habits - and one of the biggest changes is not just weight loss, but finally feeling more in control around eating.