A primer on GLP-1 receptor agonists for weight loss

It is estimated that the prevalence of adult obesity has doubled since 1990. Along with this, the number of people diagnosed with type 2 diabetes has also increased. These statistics are behind a concentrated research effort to develop new therapies that can treat both conditions. Specifically, the development of GLP-1 receptor agonists such as Mounjaro, Ozempic, Wegovy and more, have radically changed the landscape for diabetes and weight management. These medicines are the most popular prescriptions of 2024 with sales measured in the billions of dollars.

When it comes to promoting weight loss, GLP-1 (which stands for glucagon-like peptide-1) receptor agonists work by regulating a person's appetite. This happens because GLP-1s improve blood sugar control. When blood sugar is stable, a person feels less cravings for food. In addition, the absorption of glucose into the bloodstream is also slowed down. As a result of this effect, it takes longer for the stomach to empty after a meal. This makes someone feel more 'full' and for a longer period of time, decreasing the desire to eat.

Though this class of drug has received a lot of attention and interest from consumers, they are not entirely new. It was during the 1980s that the GLP-1 hormone and its role in regulating blood sugar was identified. In the early 2000s, the first GLP-1 agonist was developed to treat diabetes. Since then, many improvements have been made. In the early days of GLP-1, daily injections (two) were required. Nowadays, fewer injections may be needed; in some cases, a pill form is available.

In 2014 a GLP-1 for weight management was approved. In 2021 when Semaglutide was approved to treat obesity, public attention and interest skyrocketed. Since that time, new GLP-1s such as Tirzepatide have become available, giving patients and their providers more options to consider to aid in the achievement of weight loss.

GLP-1 agonists all share a common mechanism of action, but they differ in other key areas such as dosing frequency. So, what are some of the most popular GLP-1 options?

Semaglutide (brand names: Wegovy, Ozempic, Rybelsus)

Wegovy (weight loss) and Ozempic (type 2 diabetes) are available as a weekly injection while Rybelsus, for management of type 2 diabetes, is a daily tablet taken by mouth.

In terms of promoting weight loss, Wegovy is typically prescribed for obese adults (BMI over 30), and overweight adults (BMI over 27) with additional health issues such as high blood pressure or elevated cholesterol.  Wegovy should be used in conjunction with a reduced-calorie diet and increased physical activity to achieve weight loss. 

Liraglutide (brand names: Victoza, Saxenda)

Saxenda (weight loss) and Victoza (type 2 diabetes) are both available as a daily injection.

Saxenda can be effective for weight loss when also combined with a reduced-calorie diet and increased physical activity. Adults taking the medicine for weight loss were shown to experience a weight loss of about 8% of their starting weight.

Dulaglutide (brand name: Trulicity)

This weekly injection is taken to help manage type 2 diabetes. 

Exenatide (the first GLP-1; brand names: Byetta, Bydureon)

Both are taken for the management of type 2 diabetes; Byetta is a twice-daily injection while Bydureon is a once-weekly injection.

Ultimately the choice of medication by a physician is based on individual patient needs and preferences. Today there is ongoing research into this class of drugs to enhance their effectiveness and potentially reduce side effects. In addition, researchers are looking at combinations of GLP-1s with other medicines to provide novel treatments to patients with other conditions or multiple health challenges.

The evolution of GLP-1 agonists from diabetes treatments to broader reaching therapies illustrates a significant impact on medical science and patient care. Want to learn more? Be sure to talk to your healthcare provider!