Introduction:
For many people struggling with significant weight management issues, medical weight loss offers an effective, evidence-based approach. In recent years, medications that act as
GLP-1 receptor agonists and
GIP/GLP-1 receptor agonists have been at the forefront of medical weight loss treatments. These medications, such as
Wegovy (semaglutide) and
Mounjaro (tirzepatide), have shown promising results in helping individuals lose weight and improve overall health.
In this blog, we’ll explore how these medications work, the science behind them, and what clinical trials reveal about their effectiveness.
How Do GLP-1 and GIP/GLP-1 Receptor Agonists Work?
Medications like Wegovy and Mounjaro are designed to mimic hormones that occur naturally in the body, which regulate blood sugar, appetite, and digestion.
GLP-1 Receptor Agonists
GLP-1 (glucagon-like peptide-1) is a hormone produced in the intestines in response to food. It has several key roles:
- Stimulates insulin release: Helps the pancreas produce insulin in response to food, lowering blood sugar.
- Reduces glucagon levels: Glucagon is a hormone that raises blood sugar between meals, and GLP-1 helps suppress this.
- Slows gastric emptying: This means food stays in the stomach longer, which can increase feelings of fullness.
- Reduces appetite: GLP-1 acts on brain receptors that influence hunger, leading to reduced food intake.
Wegovy (semaglutide) is a GLP-1 receptor agonist that works by enhancing these natural processes. It is administered via a weekly subcutaneous injection.
GIP/GLP-1 Receptor Agonists
In addition to acting on the GLP-1 pathway,
Mounjaro (tirzepatide) is also a
GIP (glucose-dependent insulinotropic polypeptide) receptor agonist. GIP, like GLP-1, helps regulate blood sugar and appetite, but also influences fat metabolism and storage.
By targeting both GIP and GLP-1 receptors, tirzepatide works through multiple mechanisms to support weight loss, helping to enhance the body’s natural hormonal responses after eating.
Clinical Trial Results: How Much Weight Can Be Lost?
Both
Wegovy and
Mounjaro have been studied in large clinical trials, showing significant weight loss for people using these medications alongside lifestyle changes.
- Wegovy (semaglutide): In clinical trials, participants using Wegovy achieved an average weight loss of around 15% of their initial body weight after approximately 68 weeks of treatment. This was combined with guidance on healthy eating and exercise.
- Mounjaro (tirzepatide): In clinical trials, participants using the highest dose of Mounjaro lost an average of up to 20% of their initial body weight over a 72-week period, when used in conjunction with diet and exercise adjustments.
These figures demonstrate the potential for significant weight loss when these medications are used as part of a comprehensive weight management plan.
The SELECT Trial: What It Means for Cardiovascular Health
One of the most notable developments in medical weight loss was the recent
SELECT trial, which focused on the cardiovascular benefits of Wegovy (semaglutide). The trial involved over 17,000 adults with overweight or obesity and existing cardiovascular disease.
The results showed that patients using Wegovy experienced a
20% reduction in major cardiovascular events, such as heart attacks or strokes, compared to those who were given a placebo. This is a significant finding, as it suggests that Wegovy may not only help with weight loss but also reduce the risk of serious cardiovascular conditions for people with obesity.
This is particularly important because obesity is a major risk factor for cardiovascular disease, and treatments that target both weight and heart health can have a profound impact on long-term wellbeing.
Who is Eligible for Medical Weight Loss?
Medical weight loss treatment with medications like Wegovy and Mounjaro is not suitable for everyone. According to
NICE (National Institute for Health and Care Excellence) guidelines, these treatments are generally recommended for individuals who meet the following criteria:
- A Body Mass Index (BMI) of 30 or higher, which is classified as obese.
- A BMI of 27 or higher if they also have a weight-related medical condition such as type 2 diabetes, high blood pressure, or sleep apnoea.
Benefits vs. Risks: What to Consider
While the potential benefits of these medications—such as weight loss and a reduction in obesity-related health risks—are clear, it’s essential to weigh these against the possible side effects and risks. The benefits of these treatments should outweigh the risks, which include:
- Gastrointestinal issues: Common side effects include nausea, vomiting, diarrhoea, and constipation. These symptoms usually occur early in treatment and tend to subside as the body adjusts.
- Gallbladder problems: There is an increased risk of gallbladder-related issues such as gallstones or cholecystitis, particularly when significant weight loss occurs rapidly.
- Pancreatitis: There is a small risk of developing pancreatitis, an inflammation of the pancreas, which may require discontinuation of the medication.
- Thyroid tumours: In animal studies, GLP-1 receptor agonists have been linked to thyroid tumours, although this has not been conclusively proven in humans. However, individuals with a family history of medullary thyroid carcinoma should not use these medications.
It’s vital that any patient considering these treatments have a detailed discussion with a healthcare professional, who will assess whether the benefits outweigh the risks based on the individual’s medical history and health profile.
Side Effects: What You Should Know
As mentioned, the most common side effects of both Wegovy and Mounjaro are gastrointestinal in nature, including:
- Nausea
- Vomiting
- Diarrhoea
- Constipation
These side effects typically occur early in treatment and are usually temporary as the body adjusts to the medication. More serious but rarer side effects can include gallbladder issues, pancreatitis, and potential thyroid-related risks. Regular medical monitoring can help mitigate these risks by ensuring any side effects are managed appropriately.
Conclusion
Medical weight loss offers a scientifically-backed approach to help those struggling with obesity and weight-related conditions achieve significant, long-term results. Medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) work by mimicking natural hormones that regulate appetite, blood sugar, and metabolism, offering a powerful tool in the fight against obesity.
With clinical trials demonstrating average weight losses of up to 15-20% of body weight, and the additional cardiovascular benefits highlighted by the SELECT trial for Wegovy, these treatments have the potential to improve both physical health and quality of life.
As always, it’s important to consult with a registered healthcare provider to determine whether medical weight loss is appropriate for you, and to assess the risks and benefits based on your personal health history.
