GLP-1 for weight loss

What is GLP-1?

GLP-1 is a hormone your body naturally produces in the gut after you eat. Its full name is glucagon-like peptide-1. It plays a key role in regulating appetite, blood sugar and feelings of fullness. It helps the body release insulin and reduces appetite, which can improve blood sugar control and support weight loss.

When GLP-1 is released, it sends signals to several parts of the body. It acts on the brain to reduce appetite and increase feelings of fullness. At the same time, it slows down how quickly the stomach empties, meaning food stays in the stomach for longer. The result is that you feel satisfied sooner and stay full for longer after meals.

For people living with overweight or obesity, the body’s appetite and fullness signals can be disrupted. This can lead to increased hunger, stronger cravings and difficulty managing portion sizes. In these situations, medical treatment that strengthens GLP-1-related signals can provide valuable support.

How does GLP-1 help with weight loss?

GLP-1 analogues are used to treat both type 2 diabetes and obesity. These medicines are designed to mimic the body’s natural GLP-1 but last longer in the body. They enhance signals that are already there but may not be strong enough on their own.

The treatment works through several mechanisms at the same time. Appetite is reduced and hunger signals become weaker. Fullness tends to come earlier during a meal, which often means eating less without having to constantly fight hunger. Many people also notice less grazing and fewer cravings between meals.

In some people, GLP-1 also affects reward pathways in the brain. Interest in energy-dense foods may decrease, and emotional eating may feel easier to manage. This can make it easier to stick to recommended eating habits over time, which is key for long-term weight loss.

Examples of GLP-1-based medicines include semaglutide, available under brand names such as Ozempic and Wegovy. These medicines are well studied for blood sugar control and weight loss. There is also tirzepatide, available as Mounjaro, which acts on both GIP and GLP-1 receptors. It shares many of the same effects as semaglutide, including reduced appetite, increased fullness, slower stomach emptying and improved blood sugar regulation.

Expected results: how much weight can you lose?

Studies show that GLP-1 treatment, when combined with structured lifestyle support, can lead to clinically meaningful weight loss for many people. Results vary from person to person, but large clinical trials give us a good idea of what is possible on average.

In one head-to-head study comparing different GLP-1-based treatments, people taking semaglutide lost around 14 per cent of their starting body weight after 72 weeks on average. In the same study, people taking tirzepatide lost around 20 per cent on average over a similar period. This shows that different medicines can lead to different levels of weight loss, although both offer significant improvement compared with lifestyle changes alone.

It’s important to remember that outcomes are influenced by factors such as dose, length of treatment, consistency and the level of support around food, movement and behaviour change. The aim is not to reach a specific percentage, but to achieve sustainable weight loss that improves health over time.

Is GLP-1 a quick fix?

It’s important to be clear that GLP-1 or GIP treatment is not a shortcut or a quick fix. Overweight and obesity are chronic conditions influenced by genetics, hormones, environment and life circumstances. Medication can improve the biological conditions for change, but it does not replace the need for long-term habits. Setting realistic, measurable goals can help you stay motivated and focused.

At Yazen, GLP-1 or GIP medication is used as part of a wider treatment plan. The focus is on helping you build sustainable habits around food, movement, sleep and stress, alongside medical treatment where appropriate. Treatment is personalised and followed up regularly by a care team with medical and behavioural expertise. You should always speak to a doctor before starting GLP-1 or GIP treatment.

Who might be suitable for treatment?

Treatment with GLP-1 or GIP analogues, such as semaglutide or tirzepatide, is mainly intended for people living with overweight or obesity who meet medical criteria. In general, treatment is recommended for adults with a BMI of 30 or above, which is defined as obesity. For those with a BMI between 27 and 30, treatment may also be considered if there are weight-related health conditions such as type 2 diabetes, high blood pressure or cardiovascular disease.

These guidelines help ensure that medicines are used safely and effectively, where the benefits outweigh the risks. The decision to start treatment is always based on an individual medical assessment by a doctor, taking your overall health and previous weight loss attempts into account.

Regular medical follow-up and careful evaluation are central parts of treatment. The goal is not just weight loss in kilograms, but improved health, better quality of life and a reduced risk of long-term complications.

Possible side effects

As with any medication, side effects can occur. Common side effects of GLP-1 and GIP receptor agonists include nausea, constipation, diarrhoea, abdominal pain and vomiting. For most people, these are temporary and mild to moderate in severity. They can often be reduced by increasing the dose gradually and tailoring treatment to the individual. Increasing the dose too quickly raises the risk of gastrointestinal side effects. It’s important to be informed about common side effects before starting treatment.

GLP-1 in the treatment of type 2 diabetes

GLP-1 analogues are also used successfully in the treatment of type 2 diabetes to improve blood sugar control. By mimicking the natural GLP-1 hormone, they stimulate insulin release when blood sugar levels are high and reduce the release of glucagon. This helps keep blood sugar levels stable and reduces spikes after meals.

For best results, treatment is combined with lifestyle changes.

GLP-1 as part of long-term treatment

Weight regulation is not simply about willpower. The body actively defends its weight through biological mechanisms that can work against weight loss. This is one reason why weight regain is common after stopping treatment. With the right support, long-term weight maintenance is possible.

Physical activity and health

Physical activity is a key part of a healthy lifestyle and plays an important role if you want to lose weight and reduce the risk of type 2 diabetes over time. When GLP-1 treatment is combined with regular physical activity, weight loss may be greater and more sustainable. One reason is that movement helps the body regulate blood sugar more effectively, which strengthens the positive effects of GLP-1.

There are many ways to be active, from walking, cycling and swimming to strength training or group classes at the gym. The most important thing is finding a type of movement that suits you and that you can do regularly. Making physical activity a natural part of everyday life increases your chances of reaching your goals and maintaining your weight long term.

Physical activity may also help reduce certain side effects that can occur with GLP-1 treatment, such as constipation. Movement stimulates digestion and can help the body adjust more quickly to the medication. It also improves mood, boosts energy levels and reduces the risk of cardiovascular disease, benefits that matter for everyone, regardless of weight.

Summary

GLP-1 is a natural hormone that plays an important role in regulating appetite and fullness. Treatment based on GLP-1 can help people living with overweight or obesity reduce hunger, eat less and achieve sustainable weight loss. The best results are seen when medication is combined with lifestyle support and regular follow-up.

At Yazen, the focus is always on long-term health rather than quick results. With the right support, knowledge and medical assessment, GLP-1 can be a valuable tool for people who need more than changes to diet and exercise alone.

Frequently asked questions about GLP-1 treatment

How quickly does GLP-1 work?
Some people notice effects within a few weeks, but the full impact on appetite and weight loss usually develops gradually over several months. The dose is normally increased slowly to reduce the risk of side effects and give the body time to adjust.

Do you have to take GLP-1 for life?
There is no requirement to use GLP-1 treatment for life. For many people, longer-term treatment improves the chances of maintaining results, but decisions about duration are always individual and made together with a doctor.

Can weight come back after stopping treatment?
Weight regain is common after stopping GLP-1 treatment. Because the medication affects appetite and fullness, these signals may return to previous levels once treatment ends.

Sources

European Society of Cardiology (ESC) – Obesity and Cardiovascular Disease: an ESC Clinical Consensus Statement
https://academic.oup.com/eurheartj/article/45/38/4063/7738070

Managing the gastrointestinal side effects of GLP-1 receptor agonists in obesity: recommendations for clinical practice. Postgraduate Medicine.
https://www.tandfonline.com/doi/full/10.1080/00325481.2021.2002616

European Medicines Agency (EMA) – Wegovy (semaglutide)
https://www.ema.europa.eu/en/medicines/human/EPAR/wegovy

European Medicines Agency (EMA) – Mounjaro (tirzepatide)
https://www.ema.europa.eu/en/documents/product-information/mounjaro-epar-product-information_en.pdf

European Medicines Agency (EMA) – Ozempic (semaglutide)
https://www.ema.europa.eu/en/medicines/human/EPAR/ozempic

The New England Journal of Medicine. Once-Weekly Semaglutide in Adults with Overweight or Obesity.
https://www.nejm.org/doi/full/10.1056/NEJMoa2032183

The New England Journal of Medicine. Tirzepatide Once Weekly for the Treatment of Obesity.
https://www.nejm.org/doi/full/10.1056/NEJMoa2206038

American College of Cardiology. SURMOUNT-5: Greater Loss of Weight, Waist Circumference With Tirzepatide vs. Semaglutide.
https://www.acc.org/Latest-in-Cardiology/Journal-Scans/2025/07/10/09/09/SURMOUNT-5

BMJ. Weight Regain After Cessation of Weight Management Medications: Systematic Review and Meta-Analysis.
https://www.bmj.com/content/392/bmj-2025-085304

eClinicalMedicine. Metabolic rebound after GLP-1 receptor agonist discontinuation: a systematic review and meta-analysis. 2025.
https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(25)00614-5/fulltext

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