How are weight loss drugs suddenly everywhere?
Not long ago, managing obesity relied almost entirely on diet and exercise. Now, medications originally developed for type 2 diabetes, like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), are rewriting the rules.
These drugs target hormones in your gut that help regulate insulin, appetite, and fat metabolism. Most recently, a third-generation drug called retatrutide has emerged, targeting not just GLP-1 and GIP, but also glucagon receptors, offering a more comprehensive approach to weight management.
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Meet The Hormones: GLP-1, GIP, Glucagon
These three hormones are naturally produced by your body after meals. Each of these hormones affects how your body handles sugar, fat, and hunger signals.
GLP-1 (Glucagon-Like Peptide-1): Produced in the lower gut, it stimulates insulin, delays gastric emptying, and suppresses appetite.
GIP (Glucose-Dependent Insulinotropic Polypeptide or Gastric Inhibitory Polypeptide): Released in the upper gut, it triggers insulin release and modulates fat storage.
Glucagon: Best known for raising blood sugar, it also promotes energy burn and fat breakdown when harnessed properly.
Both GLP-1 and GIP are natural hormones made in the gut in response to eating. They act as messengers to stimulate insulin release from the pancreas in a glucose-dependent manner. This means that body only releases insulin when the blood sugar levels are high. This can reduce the risk of causing hypoglycaemia (low blood sugar level).
GLP-1 comes from the lower part of the small intestine and colon, while GIP is secreted in the upper part of the small intestine.
On the other hand, glucagon is secreted by the alpha cells of the pancreas. Often thought of as insulin’s opposite, its classic role is to raise blood sugar by telling the liver to release stored glucose. However, when strategically activated, glucagon helps amplify fat loss while preserving metabolic function.
How Do GLP-1, GIP, Glucagon Receptor Agonists Work?
Receptor agonists are medications that mimic the action of natural hormones in the body by binding to their respective receptors.
By mimicking or modulating these hormones, modern medications can shift your metabolism into a more efficient, fat-burning state, one that supports long-term weight loss and better metabolic health.
Boost insulin secretion
GLP-1 and GIP receptor agonists help the body release insulin only when the blood sugar level is high. GLP-1 makes the body more sensitive to sugar (insulin sensitivity), while GIP triggers an early insulin response right after meals.
This glucose-dependent action helps avoid dangerous blood sugar crashes (hypoglycaemia), a common issue with older diabetes drugs.
Suppress glucagon release
Glucagon is a hormone that prompts the liver to release sugar into the blood. GLP-1 reduces glucagon release from raising the blood sugar level too much after meals.
Interestingly, GIP works the opposite by supporting glucagon release to prevent dangerously low blood sugar levels. Together, both GLP-1 and GIP help to keep the blood sugar levels within the optimal range.
Delay gastric emptying
GLP-1 slows down gastric emptying, which is a process of food moving from the stomach into the small intestine for digestion.
While GIP itself does not directly slow down gastric emptying, its effects on post-meal glucose levels and satiety can indirectly result in the changes in gastric emptying rate.
This prolongs the feeling of fullness, reduces hunger signals and controls excessive food intake.
Regulate appetite
GLP-1 and GIP also act on hypothalamus (the part of the brain that controls hunger) to reduce the hunger signals. This makes it easier to stick to healthier eating habits without constant willpower battles.
Improve fat and energy use
GLP-1 and GIP may have opposing effects on fat metabolism, but together they help to maintain a healthy fat stores in the body.
GLP-1 helps break down fats, while GIP stores fats appropriately in the body. When combined, both GLP-1 and GIP promote a balanced fat distribution.
Enhanced energy use
Glucagon, when used appropriately, enhances fat burning and energy use promotes fat breakdown and energy expenditure, especially during fasting or calorie restriction. It also increases thermogenesis (aka your body’s ability to burn calories as heat).
Supports lean mass preservation
One major concern with weight loss is losing muscle along with fat.
The metabolic shift by glucagon-receptor activation encourages the body to rely more on fat for fuel, especially during periods of reduced calorie intake.
By enhancing fat metabolism, glucagon receptor activation may help preserve lean muscle mass, ensuring that weight loss is healthier and more sustainable.
Who Can Benefit from These Medications?
While these medications were initially developed to treat type 2 diabetes, their benefits go far beyond just blood sugar control. Today, they’re also being used, and actively studied, for weight loss, heart disease, kidney protection, and more.
- People with type 2 diabetes who struggle with weight management.
- Individuals with obesity or overweight issues, even without diabetes.
Beyond weight and sugar control, GLP-1 receptor agonists have demonstrated:
- Cardiovascular protective benefits
- Slowing progression of chronic kidney disease
- Benefits for Non-Alcoholic Fatty Liver Disease (NAFLD)
These medications are not suitable for everyone. They are prescription-only and should be used under medical supervision, especially for people with a history of pancreatitis, gallbladder disease, or thyroid cancer.
If you’re considering one of these treatments for weight loss, diabetes, or another metabolic condition, speak to a doctor to understand whether it’s appropriate for you.
A Powerful Tool, But Not a Magic Pill
In today’s world where appearances are often judged, many people feel the pressure to lose weight and keep a slim physique, GLP-1 and GIP receptor agonists represent a positive shift in how we manage obesity and metabolic disorders.
While these medications can help to shed weight, healthy habits can help to maintain the results in the long term.:
- Eat a balanced diet
- Cut back on processed sugars and refined carbohydrates
- Stay physically active
- Get sufficient and quality sleep
Have more questions about weight loss, GLP-1, GIP or Glucagon receptor medications?
Medical Channel Asia has launched a community forum page where you can get questions answered by a medical specialist. Why not ask them at our community forum here.
External References
- Areesha Moiz, Kristian B. Filion, Michael A. Tsoukas, Oriana HY. Yu, Tricia M. Peters, Mark J. Eisenberg. (2025). Mechanisms of GLP-1 Receptor Agonist-Induced Weight Loss: A Review of Central and Peripheral Pathways in Appetite and Energy Regulation. The American Journal of Medicine. https://www.sciencedirect.com/science/article/pii/S0002934325000592
- Liu Q. K. (2024). Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists. Frontiers in endocrinology, 15, 1431292. https://pmc.ncbi.nlm.nih.gov/articles/PMC11304055/
- Jennifer Fisher, Mms. (2025). How does ozempic work? understanding glp-1s for diabetes, weight loss, and beyond. Retrieved from https://www.health.harvard.edu/staying-healthy/how-does-ozempic-work-understanding-glp-1s-for-diabetes-weight-loss-and-beyond
- Ferhatbegović, L., Mršić, D., & Macić-Džanković, A. (2023). The benefits of GLP1 receptors in cardiovascular diseases. Frontiers in clinical diabetes and healthcare, 4, 1293926. https://doi.org/10.3389/fcdhc.2023.1293926
- Holliday, M. W., Jr, Frost, L., & Navaneethan, S. D. (2024). Emerging evidence for glucagon-like peptide-1 agonists in slowing chronic kidney disease progression. Current opinion in nephrology and hypertension, 33(3), 331–336. https://doi.org/10.1097/MNH.0000000000000976
- Nevola, R., Epifani, R., Imbriani, S., Tortorella, G., Aprea, C., Galiero, R., Rinaldi, L., Marfella, R., & Sasso, F. C. (2023). GLP-1 Receptor Agonists in Non-Alcoholic Fatty Liver Disease: Current Evidence and Future Perspectives. International journal of molecular sciences, 24(2), 1703. https://doi.org/10.3390/ijms24021703
- Mounjaro, Zepbound weight loss drugs may help lower blood pressure. (2024). Retrieved from https://www.medicalnewstoday.com/articles/hypertension-mounjaro-zepbound-weight-loss-drugs-may-help-lower-blood-pressure
- Abdul-Rahman, T., Roy, P., Ahmed, F. K., Mueller-Gomez, J. L., Sarkar, S., Garg, N., Femi-Lawal, V. O., Wireko, A. A., Thaalibi, H. I., Hashmi, M. U., Dzebu, A. S., Banimusa, S. B., & Sood, A. (2024). The power of three: Retatrutide’s role in modern obesity and diabetes therapy. European journal of pharmacology, 985, 177095. https://doi.org/10.1016/j.ejphar.2024.177095
