GLP-1 agonists are used to lower blood sugar levels to treat diabetes type 2 by releasing more insulin into the bloodstream
Some scientists hypothesize that GLP-1 decreases appetite by acting on specific areas in the brain. One side effect of GLP-1 agonists is weight loss, which is usually desired in patients with type 2 diabetes. However, GLP-1’s effects on weight haven’t been properly verified in humans without diabetes.
GLP-1 in both physiologic and pharmacologic doses promotes satiety, affects mechanistic properties of the GI tract and results in negative energy balance. Additionally, its success in promoting weight loss makes GLP-1 agonist therapy an attractive option in the management of type 2 diabetes. What needs to be balanced against this is the reported association between GLP-1 receptor agonist therapy and pancreatitis, pancreatic hyperplasia and pancreatic neoplasia .
Adverse effects of GLP-1 receptor agonists include nausea, vomiting and diarrhoea, injection-site reactions, antibody formation and increased heart rate
Glucagon like peptide-1 (GLP-1) is a 30 or 31 amino acid long peptide hormone mainly secreted by 3 tissues in the human body: enteroendocrine L cells in the distal intestine, alpha cells in the pancreas, and the central nervous system. Through its interaction with the GLP-1 receptor (GLP-1R), GLP-1 participates in the regulation of glucose homeostasis. In addition, glucagon like peptide-1 receptor agonists (GLP-1RAs) can be combined with GLP-1Rs, playing the same role as GLP-1.
Administration of GLP-1 receptor agonists stimulates GLP-1 receptors, thereby increasing insulin secretion in response to oral and intravenous glucose to similar extents; this means the magnitude of the incretin effect should remain unchanged
The drugs, also commonly known as glucagon-like peptide 1 (GLP-1) receptor agonists or GLP-1 analogues, are normally prescribed for patients who have not been able to control their condition with tablet medication.
This review provides evidence that glucagon-like peptide-1 receptor agonist therapies are associated with weight loss in overweight or obese patients with type 2 diabetes with no difference in weight loss seen between the different types of GLP-1 receptor agonists assessed.
At present, most evidence derives from cellular and animal studies, and more human data are required to determine whether this approach represents a genuine therapeutic advance.
You might be wondering why anyone would take these drugs, since they must be injected. These drugs do lower HbA1c levels, but only by 0.5% to 1.5%. They’re also only used as a second or third agent, not by themselves. One of the main draws of these drugs is that they do lead to weight loss in about 80% of users, and they seem to curb hunger, making it a good choice for people who constantly feel hungry. Weight loss eventually plateaus, however, so keep that in mind.
Many formulations of GLP-1 agonists, all of which historically were injectable and administered subcutaneously due to poor oral bioavailability, can be prescribed in the United States. Lixisenatide and liraglutide dosing are once-daily, albiglutide, dulaglutide, semaglutide dosing is once weekly, and exenatide can be dosed either as a twice-daily or a once-weekly injection. Recently, the FDA approved an oral formulation of semaglutide.