What You Should Know About GLP-1 Agonist Drugs

By Gil Blander, PhD, October 27, 2023

GLP-1 Agonist Drugs

GLP-1 agonists are medications prescribed for treating type 2 diabetes, but have received significant media attention for their weight loss effects. So what exactly are GLP-1 agonist drugs, how do they work, and what should you consider before using them to lose weight? Read on to find out.

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What are GLP-1 agonist drugs?

To understand what GLP-1 agonist drugs are and how they work, it's important to know what GLP-1 is. GLP-1 is a hormone made up of 30 or 31 amino acids. It is produced and secreted by specific cells in the intestine and certain neurons in the brainstem when food is consumed. 

Glucagon-like peptide-1 (GLP-1) drugs are a class of drugs that work by imitating the actions of glucagon-like peptide-1 to stimulate insulin production. Insulin is responsible for lowering blood sugar levels after meals. 

And where does the agonist part come in? An agonist is a molecule that attaches to a specific cell receptor and activates it to produce a biological response. Agonists are often called "activators" because they mimic the effects of the natural molecule that normally binds to the receptor and triggers a physiological response.


What do GLP-1 drugs do?

GLP-1 agonist drugs play several roles in the body—including improving diabetes outcomes and stimulating weight loss. 

How are GLP-1 drugs used for diabetes treatment and blood sugar control?

The FDA has approved GLP-1 agonists for managing type 2 diabetes as they help to reduce blood sugar levels. While researchers are studying the safety and efficacy of these medications for people with type 1 diabetes, some studies have shown that they can help lower HbA1c and promote weight loss in individuals with type 1 diabetes. [1]

It is important to note that the FDA has not yet approved GLP-1 agonists for treating type 1 diabetes, but some healthcare providers may prescribe them off-label. 

GLP-1 drugs work to control blood sugar by:

  1. Triggering insulin release from your pancreas: Insulin is an essential hormone that enables your body to use your food for energy. Insulin reduces the amount of glucose (sugar) in your blood. If you don't have enough insulin, your blood sugar rises, and consistently high blood sugar can lead to diabetes. 
  2. Blocking glucagon secretion: Glucagon is a hormone that increases blood sugar levels when necessary. GLP-1 prevents more glucose from entering your bloodstream. 

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How are GLP-1 drugs used for weight loss?

GLP-1 agonists are currently FDA-approved for the treatment of obesity due to their weight loss effects. And although these drugs were originally created as a diabetes treatment, they can lead to weight loss in those without diabetes as well. 

They can lead to weight loss in several ways, including: 

  1. Slowing stomach emptying: Slower digestion means that your body releases less glucose (sugar) from your food into your bloodstream. 
  2. Increasing satiety: GLP-1 affects areas of your brain that process hunger and satiety, making you feel fuller after eating.

In a cohort study of 175 overweight or obese patients, the total body weight loss percentages achieved were 5.9% at three months and 10.9% at six months. [2]


Can GLP-1 drugs be used for cardiovascular disease?

Multiple large cardiovascular outcome trials with novel glucose-lowering agents like GLP-1 have demonstrated robust and significant reductions in major adverse cardiovascular events and additional cardiovascular outcomes, such as hospitalizations for heart failure in a diabetic population.


What are the side effects of taking GLP-1 agonist drugs?

Generally, this medication is considered safe. However, there are some potential side effects to be aware of including loss of appetite, nausea, vomiting, and diarrhea. 

A recent study described the severe digestive issues accompanied with taking GLP-1 agonists. Compared to other weight loss drugs, using GLP-1 agonists increases the risk of pancreatitis (inflammation of the pancreas) by 9 times, bowel obstruction (blockage of the small or large intestines) by 4.5 times, and gastroparesis (a condition that slows or stops the movement of food from the stomach to the small intestine) by 3.6 times. This study highlights the importance of considering both the benefits and drawbacks of using GLP-1 agonists. [3]

It is important to keep in mind that these drugs are relatively new and the impact and long-term side effects may still be largely unknown.



How long do the effects of GLP-1 drugs last?

The form of GLP-1 used can determine how often and how long they need to be used to be effective for weight loss. Some GLP-1 agonists are stable for a day, while others are stable for a week. 

GLP-1 agonists are often taken until achieving a target weight. However, when GLP-1 agonists are discontinued, so too are the drug benefits. For example, after stopping GLP-1 agonists, appetite resumes. So, GLP-1 agonist users must incorporate other weight loss and maintenance tactics, such as exercise and adopting healthy behaviors to help maintain weight loss after taking the drug.


How expensive are GLP-1 drugs and how accessible are they compared to other weight loss drugs?

GLP-1 agonist drugs are very expensive, costing hundreds per month. And oftentimes, GLP-1 agonist drugs are not accessible to the populations that need them the most.


How to lose weight without GLP-1 agonist drugs

Excess weight is a significant risk factor for age-related diseases. Losing weight can reduce the chance of developing such diseases, leading to a better and longer life. But medications aren't the only way to approach weight loss to improve your health—changing lifestyle habits is often preferable and can have a meaningful impact.

Lifestyle changes such as increasing exercise, improving sleep, and adopting healthy eating habits are science-backed strategies to manage weight and optimize your health.

InsideTracker provides evidence-based lifestyle, exercise, and nutrition recommendations to help you live healthier longer. Learn more about our personalized wellness plans.




[1] https://diabetes.medicinematters.com/semaglutide/type-2-diabetes/a-quick-guide-to-the-sustain-trials/12206922 

[2] https://pubmed.ncbi.nlm.nih.gov/36121652/ 

[3] https://jamanetwork.com/journals/jama/fullarticle/2810542?guestAccessKey=31a6dd82-d1ee-46d6-b95e-e4ef621c2ddf&utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=100523 


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