How Do GLP-1 weight loss medications work?
GLP-1 (glucagon-like peptide-1) is a hormone naturally produced in the body, primarily after eating. It performs several functions: it reduces appetite, slows down the emptying of the stomach (helping us feel fuller for longer), and assists in regulating blood sugar levels. GLP-1 agonist medications enhance these effects – in other words, they help us eat less, stave off hunger for longer, and maintain more stable blood glucose.
Many people report that in the first few weeks of treatment, their constant hunger all but disappears, food becomes less of a focus, and resisting sugary treats or snacks becomes significantly easier. For those who have struggled with every diet they've tried, this can bring an immense sense of relief and renewed hope.
What kind of results can be expected?
While these medications aren’t instant miracle workers, they do help steady, sustainable weight loss. On average, people lose between 0.5 and 1 kg per week – especially in the first few months – though individual results vary depending on starting weight, diet, exercise levels and dosage. Often, initial weight loss is quicker due to reduced appetite and a decrease in water retention, but the pace may slow as time goes on.
Clinical trials suggest that a 10–20% reduction in body weight is possible within six to twelve months – particularly when combined with healthy lifestyle changes. Many patients experience benefits beyond the number on the scales: movement becomes easier, blood pressure improves, blood sugar stabilises, and overall wellbeing increases.
Who can be prescribed these medications?
GLP-1 agonists aren’t available over the counter and aren’t recommended for everyone who is overweight. Doctors can prescribe them if a person has a Body Mass Index (BMI) of 30 or higher, or a BMI above 27 accompanied by a weight-related health condition such as high blood pressure, elevated cholesterol, insulin resistance, type 2 diabetes or obstructive sleep apnoea.
It's essential to understand that this is not a fashionable “slimming product” – it's a prescription medication requiring professional supervision.
When Is GLP-1 treatment not suitable?
While these drugs can be life-changing for many, they aren’t appropriate for everyone. Treatment should never be started without medical consultation, as there are specific conditions that may prohibit or need care with their use.
For instance, GLP-1 agonists must not be used by those with a personal or family history of medullary thyroid cancer or those diagnosed with MEN 2 syndrome, a rare inherited endocrine disorder. The treatment is also suitable for those with a history of severe pancreatitis, as it may increase the risk of recurrence.
Patients with serious gastrointestinal problems – such as gastroparesis (delayed stomach emptying) – should also avoid these drugs, as they may worsen symptoms. Similarly, anyone with a serious kidney or liver condition requires careful assessment before beginning treatment.
It’s crucial to note that these medications are not suitable during pregnancy or breastfeeding. Conception should be avoided for at least 1–2 months after stopping treatment. And, as with all medicines, known allergies or hypersensitivities to the active or inactive ingredients are contraindications.
What are the benefits – and possible side effects?
One of the most notable benefits is the way these drugs help break the vicious cycle: we eat less, we lose weight, blood sugar and blood pressure improve, sleep quality rises, and we gain more energy. For many, it marks the first real sense of success after years of failed attempts.
However, like all medicines, GLP-1 agonists can come with side effects. The most common are mild gastrointestinal symptoms such as nausea, bloating, heartburn, constipation or diarrhoea – usually during the early stages as the body adjusts. In most cases, these subside after a few weeks. Rare but serious side effects may include intense abdominal pain or jaundice, which could indicate pancreatitis or gallstones – your doctor will always discuss these in detail before starting treatment.
How is treatment monitored?
Treatment always begins with a specialist consultation – typically with an endocrinologist, obesity specialist or diabetologist – and includes a thorough medical examination. Blood tests are used to check liver and kidney function, blood sugar levels and thyroid activity. The goals of treatment are also discussed in detail.
The medication dose is increased gradually to allow the body to adjust. Regular follow-ups (usually every three months) are essential to monitor not only weight but also overall health. Any unusual symptoms must be reported promptly – caution is key.
Why medication alone isn’t enough: The role of lifestyle changes
As promising as GLP-1 medications may be, one thing is clear: they don’t replace a healthy lifestyle. Instead, they offer valuable support in making more sustainable and lasting changes.
The drug can reduce hunger and delay appetite – but it can’t decide what you eat for dinner. If poor habits persist (e.g. fast food, high sugar intake, irregular meals), weight loss may stall or even reverse.
Lifestyle change doesn’t mean extreme dieting or ascetic living. It’s about adopting small, conscious and maintainable steps, such as:
- Regular, predictable mealtimes
- Prioritising protein- and fibre-rich foods
- Reducing refined carbohydrates and sugary drinks
- Drinking sufficient water (2–2.5 litres per day) to support satiety
- Engaging in moderate exercise at least a few times a week – even brisk walking counts!
One of the main goals is to preserve muscle mass while losing fat. This is supported by adequate protein intake and physical activity like resistance training or simple home exercises.
Many people also report an improved relationship with food: eating no longer feels like a compulsion. This presents an ideal opportunity to build healthier habits that will serve you well even after stopping the medication.
How long does treatment last – and what happens afterwards?
Duration of treatment varies from person to person. Generally, it's prescribed for at least six months, but in many cases, it may be needed for a year or more. The aim isn’t just weight loss, but embedding new habits during that time.
Obesity is a chronic condition prone to relapse. Once the medication is discontinued, it's crucial to avoid slipping back into old routines. Continued attention to diet and exercise, along with support from lifestyle coaches, dietitians or physiotherapists, can be invaluable.
GLP-1 agonists aren’t magic solutions – but when used responsibly under medical supervision and paired with meaningful lifestyle changes, they can be a powerful tool for people struggling with excess weight or type 2 diabetes. And perhaps most importantly: they offer a chance to achieve success not through self-denial, but through growing confidence and lasting change.
