Are you exploring options for managing type 2 diabetes while also aiming for weight loss? You might have come across medications like GLP-1 agonists. This class of drugs has gained significant attention for its dual benefits in controlling blood sugar and promoting weight reduction. But what exactly is GLP-1, and how do these agonists work?
This article will delve into the details of GLP-1 agonists, explaining what GLP-1 is, how these medications function, their benefits for people with type 2 diabetes, potential side effects, and how they compare to other diabetes medications like SGLT-2 inhibitors.
Understanding GLP-1 and GLP-1 Agonists
GLP-1 stands for glucagon-like peptide 1. It’s a naturally occurring hormone in your body that plays a crucial role in regulating blood sugar levels. Released from the gut after you eat, GLP-1 has several important actions:
- Stimulates Insulin Release: When blood sugar levels rise, GLP-1 signals the pancreas to release insulin. Insulin is essential for allowing glucose (sugar) to enter cells for energy, thereby lowering blood sugar levels.
- Inhibits Glucagon Secretion: GLP-1 also reduces the secretion of glucagon, another hormone that raises blood sugar by prompting the liver to release stored glucose.
- Slows Gastric Emptying: GLP-1 slows down the rate at which food empties from your stomach into the small intestine. This can lead to feeling fuller for longer and reduce overall food intake.
- Reduces Appetite: GLP-1 can also act in the brain to reduce appetite and promote feelings of satiety.
GLP-1 agonists are medications that mimic the actions of natural GLP-1. They are designed to bind to and activate the GLP-1 receptors in the body, thereby enhancing the effects of natural GLP-1. For individuals with type 2 diabetes, who often have impaired GLP-1 function, these agonists can be particularly beneficial.
Types of GLP-1 Agonists
GLP-1 agonists are available in injectable and oral forms. Here’s a breakdown of the commonly prescribed GLP-1 agonists, categorized by their administration frequency:
Injectable GLP-1 Agonists:
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Daily Injections:
- Liraglutide (Victoza, Saxenda): Administered once daily. Saxenda is a higher dose of liraglutide specifically approved for weight management.
- Lixisenatide (Adlyxin): Taken once a day.
- Exenatide (Byetta): Injected twice daily.
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Weekly Injections:
- Dulaglutide (Trulicity): A once-weekly injection.
- Exenatide extended-release (Bydureon BCise): Administered once every week.
- Semaglutide (Ozempic): A weekly injection. Ozempic is widely recognized for its effectiveness in both blood sugar control and weight loss.
- Tirzepatide (Mounjaro): While technically a dual GLP-1 and GIP receptor agonist, Tirzepatide is often grouped with GLP-1 agonists due to its similar mechanism and benefits. It’s injected once a week and has shown significant efficacy in both glucose management and weight reduction.
Oral GLP-1 Agonist:
- Semaglutide (Rybelsus): This is the oral form of semaglutide, taken as a pill once daily. It offers the convenience of an oral medication while still providing GLP-1 agonist benefits.
It’s worth noting that the effectiveness of GLP-1 agonists in promoting weight loss can vary depending on the specific medication and dosage. Studies indicate that tirzepatide and semaglutide generally lead to the most significant weight loss, followed by dulaglutide and liraglutide. However, all GLP-1 agonists tend to result in more weight loss compared to not taking these medications.
How GLP-1 Agonists Aid in Weight Loss
While the primary function of GLP-1 agonists is to improve blood sugar control in type 2 diabetes, their impact on weight loss is a significant and welcomed benefit for many patients. The weight loss associated with these medications is thought to be due to several factors:
- Appetite Regulation: GLP-1 agonists can reduce appetite by acting on the brain’s appetite centers, helping individuals feel less hungry and consume fewer calories.
- Delayed Gastric Emptying: By slowing down the movement of food from the stomach, these medications can prolong feelings of fullness after eating, contributing to reduced food intake.
- Potential Calorie Reduction: Through appetite and gastric emptying effects, individuals often naturally reduce their calorie consumption without consciously restricting their diet.
Potential Side Effects of GLP-1 Agonists
Like all medications, GLP-1 agonists can have side effects. It’s important to be aware of these potential effects and discuss them with your healthcare provider.
Common Side Effects:
- Gastrointestinal Issues: Nausea, vomiting, and diarrhea are among the most common side effects, especially when starting treatment. These symptoms often subside over time as the body adjusts to the medication.
- Headache: Some individuals may experience headaches.
Serious Side Effects and Precautions:
- Hypoglycemia (Low Blood Sugar): The risk of hypoglycemia is generally low with GLP-1 agonists when used alone. However, this risk can increase significantly if they are taken in combination with other diabetes medications that lower blood sugar, such as sulfonylureas or insulin. It’s crucial to monitor blood sugar levels closely, especially when starting or adjusting dosages of these combined medications.
- Pancreatitis: There is a potential risk of pancreatitis (inflammation of the pancreas), although it’s considered rare.
- Thyroid Tumors: Studies in rats have linked GLP-1 agonists to certain thyroid tumors. While the risk to humans is not yet fully understood and is under ongoing investigation, GLP-1 agonists are generally not recommended for individuals with a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia syndrome type 2 (MEN 2).
- Other Contraindications: GLP-1 agonists may not be suitable for individuals with a history of pancreatitis, severe gastrointestinal issues like gastroparesis, certain types of kidney disease, or for women who are pregnant or breastfeeding.
It’s essential to have a thorough discussion with your doctor about your medical history and any existing conditions before starting a GLP-1 agonist.
GLP-1 Agonists vs. SGLT-2 Inhibitors
Besides GLP-1 agonists, Sodium-Glucose Co-transporter 2 (SGLT-2) inhibitors are another class of type 2 diabetes medications that can promote weight loss. SGLT-2 inhibitors work differently by increasing the excretion of glucose through the urine, thereby lowering blood sugar and reducing calories.
While both classes offer benefits for blood sugar control and weight management, there are some key differences:
- Weight Loss Effectiveness: Generally, GLP-1 agonists tend to result in more significant weight loss compared to SGLT-2 inhibitors.
- Mechanism of Action: GLP-1 agonists work by mimicking a hormone to enhance insulin release and reduce appetite, while SGLT-2 inhibitors increase glucose excretion via the kidneys.
- Side Effect Profiles: Common side effects differ. SGLT-2 inhibitors are associated with an increased risk of genital yeast infections and urinary tract infections, while GLP-1 agonists more commonly cause gastrointestinal issues.
SGLT-2 Inhibitors Examples:
- Canagliflozin (Invokana)
- Dapagliflozin (Farxiga)
- Empagliflozin (Jardiance)
- Ertugliflozin (Steglatro)
- Bexagliflozin (Brenzavvy)
Additional Health Benefits
Beyond blood sugar control and weight loss, both GLP-1 agonists and SGLT-2 inhibitors have shown potential benefits for cardiovascular and kidney health. Studies suggest that some medications in these classes may reduce the risk of heart disease, heart failure, stroke, and kidney disease progression in individuals with type 2 diabetes. It is still under investigation whether these benefits are directly from the medications themselves or secondary to weight loss and improved metabolic health.
Is a GLP-1 Agonist Right for You?
If you have type 2 diabetes and are interested in managing your weight and blood sugar, GLP-1 agonists could be a valuable option to consider. However, the best approach to diabetes management is individualized. It’s crucial to have an open conversation with your diabetes care team to determine if a GLP-1 agonist or another type of medication is appropriate for your specific health needs and goals. They can help you weigh the potential benefits and risks, considering your overall health profile and preferences, to make the most informed decision.
References:
- Pharmacological approaches to glycemic treatment: Standards of care in diabetes — 2024. Diabetes Care. 2024; doi:10.2337/dc24-S009.
- Obesity and weight management for the prevention and treatment of type 2 diabetes: Standards of care in diabetes — 2024. Diabetes Care. 2024; doi:10.2337/dc24-S008.
- Oral and injectable medications for type 2 diabetes. American Diabetes Association. https://diabetes.org/health-wellness/medication/oral-other-injectable-diabetes-medications. Accessed Oct. 23, 2024.
- DeSantis A. Sodium-glucose cotransporter 2 inhibitors for the treatment of hyperglycemia in type 2 diabetes mellitus. https://www.uptodate.com/contents/search. Accessed Oct. 23, 2024.
- Tirzepatide. Merative Micromedex. https://www.micromedexsolutions.com. Accessed Oct. 24, 2024.
- Dungan K, et al. Glucagon-like peptide 1 receptor agonists for the treatment of type 2 diabetes mellitus. https://www.uptodate.com/contents/search. Accessed Oct. 24, 2024.
- Goldman L, et al., eds. Diabetes mellitus. In: Goldman-Cecil Medicine. 27th ed. Elsevier; 2024. https://www.clinicalkey.com. Accessed Oct. 24, 2024.
