GLP‑1 medications have become one of the most widely discussed treatments for weight management. While they may help some people living with obesity, they have also raised many questions.
How do GLP‑1 medications work? Who may be suitable for them? What side effects can occur? What happens when treatment stops? How do they compare with metabolic or bariatric surgery?
Understanding the role of these medications starts with understanding obesity itself.
Obesity is a complex, chronic health condition influenced by many factors, including genetics, hormones, metabolism, health conditions, medicines, sleep, emotional wellbeing and a person’s environment. It is not simply a matter of willpower.
Like other chronic conditions, there is no single treatment that will be right for everyone. Treatment may include nutrition and physical activity support, behavioural strategies, prescription medication, metabolic surgery or a combination of approaches.
Key Takeaways
- GLP‑1 medications are prescription medicines: They act on biological pathways involved in appetite, blood glucose and digestion.
- They are not suitable for everyone: An appropriately qualified health professional must assess a person’s health, medical history, current medicines and individual circumstances.
- Responses vary: Some people experience meaningful changes in appetite, weight or metabolic health, while others have more modest results or cannot tolerate the side effects.
- Side effects and monitoring matter: Digestive symptoms are common, and some people may experience more serious complications.
- Treatment is usually life long: Appetite and weight-regulating signals change after medication is stopped, and weight regain is the norm.
- Medication and surgery are similar options: Neither approach is automatically better, and sometimes combining the two is necessary. The appropriate treatment depends on an individual clinical assessment.
What Are GLP‑1 Medications?
GLP‑1 stands for glucagon-like peptide‑1. It is a hormone naturally released by the gut after eating.
GLP‑1 receptor agonists are prescription medicines that act in a similar way to this hormone. Some related medicines act on GLP‑1 as well as another hormone pathway. Although these medicines are often discussed together, their approved uses, dosing, benefits, risks and side effects are not necessarily the same.
Some GLP‑1 medicines are approved in Australia for particular people living with type 2 diabetes. Some are approved for chronic weight management in people who meet specific clinical criteria. A medicine approved for one condition is not automatically approved or appropriate for another.
A doctor must determine whether a particular medicine is clinically suitable. Treatment should only be used as prescribed and obtained through a legitimate Australian healthcare pathway.
How Do GLP‑1 Medications Work?
GLP‑1 medications affect several areas of the body, including the brain, pancreas and digestive system. Essentially they interfere with the process that drive the body to maintain a high weight, and metabolic ill health.
Depending on the medicine and the individual, they may:
- Reduce hunger
- Increase feelings of fullness after eating
- Slow the rate at which food leaves the stomach
- Influence insulin release and blood glucose regulation
- Help some people feel satisfied after eating a smaller amount
These medicines do more than simply tell someone to “eat less”. They affect biological pathways involved in appetite and metabolism.
The hypothalamus is an area of the brain involved in regulating hunger, energy balance and body weight. The body also has biological systems that work to maintain weight within a certain range. This is sometimes described as a person’s “defended body weight”.
GLP‑1 medications may influence some of the signals involved in hunger and fullness. Some people report feeling less hungry, experiencing fewer food cravings or feeling full sooner.
The response varies considerably between individuals. Not everyone will experience the same changes or obtain the same health outcomes.
Are GLP‑1 Medications a Cure for Obesity?
No. GLP‑1 medications do not cure obesity.
Obesity is a chronic condition, and medication is generally considered one part of a broader management plan. That plan may also address nutrition, physical activity, sleep, emotional wellbeing, medical conditions and ongoing healthcare support.
The effects of a GLP‑1 medication depend on treatment continuing. If medication is stopped, hunger and other weight-regulating signals usually increase again. Most people regain weight after stopping treatment.
This does not mean that treatment has failed. It reflects the long-term biological processes involved in obesity. Before starting medication, patients should discuss the likely duration of treatment, ongoing costs, monitoring and what may happen if treatment needs to be stopped.
Who May Be Suitable for GLP‑1 Medication?
GLP‑1 medications are not intended for everyone who wants to lose weight.
They may be considered for some people living with obesity or for some people who are above a healthy weight and have related health conditions. The exact eligibility criteria depend on the medicine’s approved Australian indication and the person’s clinical circumstances.
An assessment may consider:
- Medical history and current health conditions
- Current medicines and possible interactions
- Previous approaches to weight management
- Type 2 diabetes or other metabolic conditions
- Digestive or gallbladder conditions
- Previous pancreatitis
- Kidney health and the risk of dehydration
- Mental health and eating disorder history
- Pregnancy, breastfeeding or plans for pregnancy
- Upcoming surgery, endoscopy or another procedure
- The person’s treatment preferences and goals
- The need for ongoing monitoring and follow-up
The decision to prescribe a GLP‑1 medication should be made with an appropriately qualified healthcare professional. Patients should not use another person’s medication or change their dose without medical advice.
Do GLP‑1 Medications Work for Everyone?
No medical treatment produces the same result for every person.
Some people experience meaningful changes in appetite, body weight, blood glucose or weight-related health. Other people have a more modest response, experience little benefit or find the treatment difficult to tolerate.
This variation is not simply about motivation or willpower. Genetics, hormones, metabolism, health conditions and other biological factors can all influence how someone responds.
Progress should be reviewed using more than weight alone. Depending on the person, treatment goals may also include changes in blood glucose, blood pressure, mobility, sleep, energy levels or other weight-related health concerns.
A prescriber should review whether the treatment remains safe, appropriate and useful over time.
What Are the Possible Side Effects?
Like all prescription medicines, GLP‑1 medications can cause side effects.
Common side effects involve the digestive system and may include:
- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Abdominal discomfort
- Bloating
- Reflux
- Reduced appetite
Digestive side effects may be more noticeable when treatment begins or the dose changes. Patients should follow their prescriber’s instructions and seek advice if symptoms are persistent, severe or affecting their ability to eat and drink.
Less common but potentially serious problems can occur. Seek prompt medical advice for symptoms such as:
- Severe or persistent abdominal pain
- Repeated vomiting or an inability to keep fluids down
- Signs of dehydration
- Yellowing of the skin or eyes
- Symptoms of a serious allergic reaction
- Significant or concerning changes in mood
- Thoughts of self-harm or suicide
GLP‑1 medicines can slow stomach emptying. This may be relevant before surgery, endoscopy, sedation or a general anaesthetic. Tell your surgeon, anaesthetist and other treating health professionals about all medicines you use. They will advise whether any changes are required before a procedure.
This is not a complete list of risks or side effects. Patients should read the Consumer Medicine Information for their prescribed medicine and speak with their doctor or pharmacist.
What Happens if GLP‑1 Medication Is Stopped?
The effects of GLP‑1 medication are temporary, so reduce after treatment stops. Hunger or food-related thoughts may increase again, and most people regain a lot, or all of the weight they lost.
There are many reasons treatment may be changed or stopped, including side effects, cost, availability, pregnancy planning, a medical procedure or a change in health circumstances.
Medication should not be stopped or restarted without guidance from the treating health professional. A planned review can help determine the safest next steps and whether another form of support is appropriate.
How Do GLP‑1 Medications Compare With Metabolic Surgery?
GLP‑1 medications and metabolic surgery are both used within the broader management of obesity, but they work differently and have different risks, benefits and follow-up requirements.
GLP‑1 Medications
GLP‑1 medications influence appetite, blood glucose and digestive signals while treatment continues. They do not involve an operation, but they require a prescription, monitoring and review.
Possible considerations include side effects, ongoing costs, medicine availability, the need for continued treatment and the possibility of weight regain after stopping.
Metabolic or Bariatric Surgery
Metabolic surgery changes the anatomy of the digestive system and its communication with the brain. Depending on the procedure, it can affect appetite, fullness, gut hormones, reflux and metabolism.
Surgery involves an operation, anaesthesia and a recovery period. It also carries surgical and nutritional risks and requires long-term follow-up. Blood tests and vitamin or mineral supplements may be needed.
Is One Treatment Better Than the Other?
One treatment is not automatically better than the other.
Some people may be suited to medication, while others may be considered for metabolic surgery. Some people may use both approaches at different stages of care.
The appropriate option depends on factors such as:
- Overall health
- Weight-related health conditions
- Previous treatment
- Previous abdominal or bariatric surgery
- Reflux or other digestive symptoms
- The likely benefits and risks
- Treatment preferences
- Readiness for ongoing monitoring and follow-up
Comparisons should be discussed as part of an individual assessment rather than based on general claims or another person’s experience.
Choosing the Right Treatment
There is no one-size-fits-all approach to obesity management.
The most appropriate treatment is one that suits the person’s clinical circumstances, is supported by evidence and can be monitored safely. For some people, nutrition, activity and behavioural support may be appropriate. Others may be considered for prescription medication, metabolic surgery or a combination of approaches.
A comprehensive assessment helps ensure that treatment decisions consider overall health rather than body weight alone.
Useful questions to ask include:
- Why might this treatment be appropriate for me?
- What benefits could I reasonably expect?
- What are the common and serious risks?
- How long might treatment continue?
- What monitoring will I need?
- How could treatment affect my other medicines or health conditions?
- What should I do before surgery or another procedure?
- What may happen if treatment is stopped?
- What alternatives are available?
- What costs are involved?
Discussing Your Options
If you’re living with obesity or obesity-related health conditions and are wondering whether GLP-1 medication may be appropriate for you, speaking with your GP is an important first step.
Where clinically indicated, your GP may refer you for specialist assessment.
Dr Alex Craven is a Consultant General, Upper Gastrointestinal and Bariatric Surgeon who provides comprehensive assessment and management of obesity. During a consultation, he takes the time to understand each patient’s medical history, health goals and individual circumstances before discussing the evidence-based treatment options that may be appropriate. Depending on the patient’s needs, this may include lifestyle interventions, medication, metabolic surgery, or a combination of approaches as part of an individualised management plan.
For more information or to book with Dr Alex Craven , call (03) 9852 3777 or email info@dralexcraven.com.au.
Disclaimer: This article is intended for general information only and should not be considered medical advice. Every person’s circumstances are different. If you have questions about obesity management or GLP-1 medications, please speak with your GP or another qualified healthcare professional.
FAQs
Are GLP‑1 medications insulin?
No. GLP‑1 receptor agonists are not insulin. However, some are used as part of diabetes management and may affect blood glucose. People taking other diabetes medicines may need additional monitoring or changes to their treatment.
How long do GLP‑1 medications take to work?
The response and timeframe vary according to the medicine, dose and individual. Treatment is often introduced gradually, and progress should be reviewed by the prescriber. Not everyone will have the same result.
Can GLP‑1 medication replace metabolic surgery?
Not necessarily. Medication and surgery work differently and have different risks, benefits and follow-up requirements. An individual clinical assessment is needed to determine which options may be appropriate.
Can I take a GLP‑1 medication before surgery or an endoscopy?
GLP‑1 medications can slow stomach emptying, which may affect preparation for sedation or anaesthesia. Tell your surgeon, anaesthetist and treating team that you use the medication. Follow their individual instructions rather than stopping it yourself.
Who should I speak with about GLP-1 medication?
Start with your GP or the health professional managing your diabetes or obesity care. They
can assess your health, explain suitable options and arrange referral where needed.
