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How does GLP-1 work for weight loss?

Written on November 29, 2022 by Theresa Vuskovich, DMD. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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Weight loss is challenging, especially if you have a condition such as diabetes. When it comes to weight loss, there are no quick fixes, but medications are available to assist you. GLP-1s are prescription weight loss medications available through your healthcare provider. This article explains how GLP-1 works for weight loss and gives you an overview of the treatment options you might discuss with your healthcare provider. First, let's review some of the basics of GLP-1.

What are GLP-1s?

The Food and Drug Administration (FDA) approved GLP-1 medications in 2005 to treat type 2 diabetes [5]. Type 2 diabetes is the most common form of diabetes, accounting for 95% of the 463 million people with diabetes worldwide [5]. Type 2 diabetes occurs when the body doesn't produce sufficient insulin, which helps regulate sugar levels. GLP-1s are not indicated for type 1 diabetes, a genetic condition often diagnosed in childhood [5].

GLP-1 stands for glucagon-like peptide-1, which is an intestinal hormone that is released after eating to increase insulin secretion [6]. GLP-1s, also known as GLP-1 receptor agonists (GLP-1RAs), stimulate the release of insulin, keeping blood sugar levels normal [3,5,9]. A side effect of GLP-1s is weight loss, which led to its testing as an anti-obesity drug.

Why do GLP-1s lead to weight loss?

Now that you know more about GLP-1s, let's explore how they help you lose weight. GLP-1 controls appetite and weight through a complex series of brain-gut reactions [8]. GLP-1s work by activating GLP-1 receptors, which leads to the following effects [7,8]:

  • Increased insulin production
  • Reduced glucagon release
  • Reduced appetite
  • Delayed gastric emptying

Researchers are still investigating how GLP-1s cause weight loss. Nevertheless, the increase in GLP-1 receptor activity makes the stomach empty slower and regulates the brain's hunger signals. As a result, you will feel satisfied with fewer calories and lose weight [8]. Even if you take a GLP-1, your healthcare provider will recommend a healthy diet and consistent exercise routine.

Which GLP-1s are available for weight loss?

The two types of GLP-1s are short-acting and long-acting. In general, long-acting GLP-1s are more effective than short-acting GLP-1s for weight loss [8,10]. The following are GLP-1s approved by the FDA for weight loss [1,3,4,11]:

  • Liraglutide (Saxenda)
  • Semaglutide (Wegovy™)

The FDA approved these two long-acting GLP-1s in 2014 and 2021, respectively, as anti-obesity medications [1]. Even though semaglutide and liraglutide both treat type 2 diabetes, additional studies found that liraglutide and semaglutide also reduce weight, regardless if you have type 2 diabetes. [5,11]. During the clinical trials, 86.4% of patients on semaglutide lost 5% of their weight at week 68 versus 31.5% in the placebo group [11].

Obesity is a public health crisis. One-third of Americans are overweight, according to the body mass index (BMI) [6]. Overweight individuals are those with a body mass index (BMI) greater than or equal to 25, while obesity is defined as a BMI of 30 or higher [4]. Obesity increases the risk of nerve and kidney damage due to diabetes, heart disease, high blood pressure, stroke, depression, poor COVID-19 outcomes, cancer, and mortality [4]. You can reduce your risk of heart disease by losing 5% to 10% of your body weight if you are overweight [1].

In addition to promoting weight loss, both of these long-acting GLP-1s improved A1C test results more than short-acting GLP-1s [4,8]. If you have diabetes, you are familiar with the HbA1c or A1C blood test, which measures the amount of sugar in your red blood cells over the previous 2-3 months. A1C results help you and your healthcare provider determine if your current exercise, diet, and medications are helping you manage your diabetes.

While liraglutide and semaglutide are effective for weight loss and A1C reduction, they do have disadvantages. They can cause more side effects than short-acting GLP-1s [9]. Side effects include dizziness, vomiting, and diarrhea. Additionally, both require an injection [9,11].

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How do you get GLP-1s to lose weight?

GLP-1s require a prescription from your healthcare provider. First, your healthcare provider will determine if you meet the criteria. Adults who have a BMI index of 30 kg/m^2 or higher (obesity) or 27 kg/m^2 or greater (overweight) with at least one weight-related health problem (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia) may benefit from GLP-1 injections combined with physical activity and a reduced calorie diet [11].

Along with prescribing a GLP-1, your healthcare provider will help you lose weight through lifestyle changes. Your healthcare provider will help you determine what diet, exercise, and medications are best for you. GLP-1s aren't safe for everyone and can interfere with other medications, so talk to your healthcare provider before taking them.

With Everlywell, you can learn more about your health at home. Everlywell provides wellness tests to track your overall health. Browse our collection of Everlywell tests or learn more about the HbA1c test.

What are the GLP-1 drugs?

Do you need a prescription for GLP-1?

What is an agonist?

GLP-1 medications and exercise used together for type 2 diabetes: what to know

Getting insurance coverage for weight loss drugs like Wegovy®, Ozempic® and other GLP-1s

Take our weight loss quiz to determine some helpful next steps for your weight loss efforts.


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  2. Garvey W, Mechanick J, Brett E, et al. American Association of Clinical Endocrinologists and American College of Endocrinology comprehensive clinical practice guidelines for medical care of patients with obesity. Endocr Pract. 2016;22(Suppl 3):1-203. Accessed November 29, 2022. URL
  3. Hughes S, Neumiller JJ. Oral Semaglutide. Clin Diabetes. 2020;38(1):109-111. doi:10.2337/cd19-0079. URL
  4. Idrees Z, Cancarevic I, Huang L. FDA-approved pharmacotherapy for weight loss over the last decade. Cureus. 2022;14(9):e29262. doi:10.7759/cureus.29262. URL
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  6. Overweight & obesity statistics. National Institute of Diabetes and Digestive and Kidney Diseases. Published September 16, 2022. Accessed November 29, 2022. URL
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  9. Trujillo JM, Nuffer W, Smith BA. GLP-1 receptor agonists: an updated review of head-to-head clinical studies. Ther Adv Endocrinol Metab. 2021;12:2042018821997320. Published 2021 Mar doi:10.1177/2042018821997320. URL
  10. Vosoughi K, Atieh J, Khanna L, et al. Association of glucagon-like peptide 1 analogs and agonists administered for obesity with weight loss and adverse events: A systematic review and network meta-analysis. EClinicalMedicine. 2021;42(101213):101213. doi:10.1016/j.eclinm.2021.101213. URL
  11. Wegovy® [package insert]. Plainsboro, NJ: Novo Nordisk Inc.; 2021. Accessed November 29, 2022. URL
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