All About GLP-1s


What are GLP-1s?

People with type 2 diabetes have many medication options to manage the disease. Most are familiar with insulin or metformin, but there’s another class of drugs that are called glucagon-like peptide-1 receptor agonists, shortened to GLP-1 RAs or GLP-1s.

The first GLP-1, exenatide (Byetta) was first approved by the U.S. Food and Drug Administration (FDA) in 2009 as a twice-daily injectable, intended to be taken within an hour of morning and evening meals. Up until 2019, GLP-1s were only injectable medications when Rybelsus, the first oral GLP-1 came to market.

Different GLP-1s have different dosing requirements, such as:

Once-daily injections:

  • Lixisenatide (Brand name: Adlyxin)
  • Liraglutide (Brand names: Victoza, Saxneda)

Once-weekly injections:

  • Dulaglutide (Brand name: Trulicity)
  • Semaglutide (Brand name: Ozempic)
  • Extended-release exenatide (Brand names: Bydureon, Bydureon BCise)

Before Meals: 

  • Oral semaglutide (Brand name: Rybelsus) taken 30 to 60 minutes before meals

Naturally-Produced GLP-1 vs. GLP-1 Medications

Before we dive into the medication GLP-1, let’s discuss what the hormone does naturally. The natural hormone, called endogenous GLP-1 produced by the body is released in response to glucose. When released, it helps increase the secretion of insulin and reduce the hormone that raises blood glucoseglucagon. The hormone also slows digestion and suppresses appetite signals—this helps reduce hunger and improve satiety.

So why are there GLP-1 medications if we produce the hormone naturally? 

That’s a great question! GLP-1 RAs exist because endogenous GLP-1s have a short half-life, are rapidly broken down by DPP4-enzymes (another class of type 2 medications), and people with type 2 diabetes have lower amounts of natural GLP-1 than people without diabetes. Therefore, the GLP-1 agonists were created to mimic the naturally-produced hormone without breaking down quickly.

When GLP-1s are Needed

GLP-1 RAs, along with other medications, are recommended when glycemic goals aren’t being met within three months, even with metformin and other lifestyle changes. The new 2021 American Diabetes Association’s Standards of Care shows a chart of when GLP-1s and other medications should be recommended to patients. Recommendations depend on other factors such as risks for cardiovascular disease, heart failure, chronic kidney disease, the need to minimize hypoglycemia and weight loss or gain.

For example, in the chart mentioned above, if a patient has a high risk or established Atherosclerotic Cardiovascular Disease (ASCVD), one of the recommended medication strategies is to prescribe a GLP-1 with proven CVD benefits (label indication of reducing CVD events).

Using GLP-1s with Insulin

If a patient is on insulin therapy and their A1C remains above the designated target, a doctor may recommend a GLP-1. The combination of long-acting insulin, also called insulin glargine. basal insulin and a GLP-1 is strongly effective in lowering blood sugar with less weight gain and hypoglycemia compared to intensified insulin regimens. 

There are currently two dual-combination insulin/GLP-1 RA products available: insulin glargine plus lixisenatide and insulin degludec plus liraglutide. Both medications are once-daily injections.

GLP-1s Benefit Heart Health

Other than helping improve type 2 diabetes management, GLP-1s can benefit patients with cardiovascular health problems or at risk for them. The Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial assessed the effect of the GLP-1, liraglutide, on cardiovascular health. Results showed that deaths from cardiovascular diseases were greatly reduced in patients who took liraglutide compared to those who didn’t.

The promising results from this study led to the approval of liraglutide by the FDA to reduce the risk of major cardiovascular events (MACE) such as heart attack, stroke and death in adults with type 2 diabetes and established cardiovascular disease. Other GLP-1s, such as semaglutide and dulaglutide, have also been provided after results showed their effectiveness in reducing MACE in the SUSTAIN-6 and REWIND trials, respectively.

Costs of GLP-1s

Individual costs for GLP-1 agonists vary depending on your health insurance plan, but according to a recent study, annual out-of-pocket costs in Medicare Part D plans for GLP-1 agonists range from $2,000 to 2,500. Websites like GoodRx also list prices for various GLP-1 agonists. Wholesale prices can range from $750 to nearly $1200.

Side Effects of GLP-1s

Side effects of using GLP-1s include:

  • Nausea
  • Diarrhea
  • Vomiting
  • Injection Site Reactions
  • Hypoglycemia
  • Contraindicated for people with a personal or family history of thyroid cancer and pancreatitis.
  • GLP-1s are not recommended for patients with severe gastrointestinal disease of gastroparesis.

Key Takeaways:

  • GLP-1s are a kind of injectable medication to help treat type 2 diabetes. Brand names include Trulicity and Ozempic. The only oral on the market GLP-1 is Rybelsus.
  • GLP-1 RA stands for glucagon-like peptide-1 receptor agonist.
  • They help with type 2 diabetes management by increasing the secretion of insulin, suppressing appetite and slowing digestion.
  • This medication can be taken once weekly, daily, or before meals, depending on the kind of GLP-1 medication.
  • GLP-1s are recommended if glucose targets aren’t reached within three months as part of dual therapy with metformin or basal insulin. It’s also recommended in patients with or at risk for cardiovascular diseases, patients who need to minimize hypoglycemia or lose weight.
  • Other benefits of GLP-1s include weight loss.

For more information on how GLP-1s can benefit you and your loved one in managing type 2 diabetes, please consult a doctor.

Learn about other diabetes medications:

Type 2 Guide to Oral Medications

Type 2 Guide to Insulin

All About Sulfonylureas

All About SGLT-2s

This content was made possible with the support of Trulicity, a partner of Beyond Type 2. 

WRITTEN BY T'ara Smith, MS, Nutrition Education, POSTED 01/15/21, UPDATED 07/27/23

T’ara was diagnosed with type 2 diabetes in July 2017 at the age of 25. Since her diagnosis, she focused her academic studies and career on diabetes awareness and living a full life with it. She’s excited to have joined the Beyond Type 1 team to continue her work. Two years later, T'ara discovered she'd been misdiagnosed with type 2 and actually has latent autoimmune diabetes in adults (LADA). Outside the office, T’ara enjoys going to the movies, visiting parks with her dog, listening to BTS and cooking awesome healthy meals. T’ara holds an MS in Nutrition Education from American University.