What Is a GLP-1 Receptor Agonist?
GLP-1 receptor agonists are a type of non-insulin injectable, a medication that is injected under the skin via syringe or pen device.
Used together with diet and exercise, it may help patients with type 2 diabetes lose weight, reduce hemoglobin A1C, and potentially reduce risk of cardiovascular death.
Who Is It For?
Although this option is making its way into the forefront of type 2 diabetes care, it is not a first-line treatment—research into its effects is ongoing and it can be expensive. It is also not recommended for everyone, particularly those with a history of pancreatitis, gastroparesis, and certain types of cancer. If you’re interested, discuss the benefits and potential side effects with your doctor.
What Do GLP-1 Agonists Do?
GLP-1 agonists mimic the body’s natural GLP-1 hormone, which is lower in people with diabetes. This hormone is normally released from your small intestine when you eat.
It works to slow down the process by which food leaves your stomach, which can promote weight loss and control your blood glucose levels after meals.
The agonists also act on the stomach, brain, pancreas, and liver.
Effects on the Brain
GLP-1 agonists send a signal to the brain, specifically the hypothalamus, telling it to decrease water and food intake. As a result, you get full more quickly, consume less food, and lose weight.
Because your thirst sensation may decrease, it’s important to remember to drink plenty of fluids to prevent dehydration.
Effects on the Pancreas
GLP-1 increases insulin secretion from the pancreas, helping to lower after-meal blood glucose levels.
Generally, after you eat a meal, your body converts carbohydrates to glucose molecules and absorbs them into the bloodstream. Insulin then helps transport the glucose from the bloodstream and into cells, lowering the levels in your blood.
Effects on Glucagon
In addition, GLP-1 decreases secretion of a hormone called glucagon. Glucagon’s job is to prevent blood sugars from dipping too low.
In people with type 2 diabetes, glucagon can actually cause blood glucose levels to rise too high because either 1) there is not enough insulin to help lower blood sugar or 2) the body is less able to respond to insulin. Therefore, by lowering glucagon secretion, blood sugars are reduced.
Effects on the Stomach
GLP-1 decreases acid secretion and slows gastric emptying, or how quickly food leaves your stomach, therefore both increasing feelings of fullness and reducing how quickly blood glucose rises.
Increased fullness also often results in eating less, which typically causes weight loss. Weight loss, in turn, decreases insulin resistance to help lower blood glucose.
Effects on the Liver
GLP-1 lowers how much glucose the liver puts out, which may result in lower blood glucose levels. It works by increasing gluconeogenesis, a process that generates glucose from non-carbohydrate substances such as protein and fat.
As gluconeogenesis increases, receptors for glucagon (the hormone that helps to increase blood glucose) are reduced in the liver, decreasing glucose formation and stimulating cells to take up glucose from the blood stream, thus lowering blood glucose.
Read more about the different types of GLP-1 agonists and their benefits and drawbacks here.