GLP-1 Agonists: Getting to Know These Diabetes Drugs Better

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GLP-1 Agonists: Getting to Know These Diabetes Drugs Better

If you have type 2 diabetes, it’s good to know that, when it comes to medication, there are many options to choose from. One choice is the GLP-1 agonists. Learn more about this class of medications, including whether they might be right for you.

How do GLP-1s work?

People who have type 2 diabetes don’t make enough of the hormones gastric inhibitory peptide (GIP) and glucagon-like peptide-1 (GLP-1). GLP-1 agonist medications replace what the body isn’t making enough of. GLP-1 agonists work in several ways to help lower blood glucose levels, by:

  • Slowing down stomach emptying
  • Reducing the release of glucagon (a hormone that raises blood glucose) from the liver
  • Increasing the release of insulin from the pancreas
  • Signaling the brain that you are full and that it’s time to stop eating (which helps with weight loss)

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What GLP-1 agonists are available?

There are several medications in the GLP-1 agonist class. These include:

  • Victoza (liraglutide), taken by injection daily
  • Adlyxin (lixisenatide), taken by injection daily
  • Byetta (exenatide), taken by injection twice daily
  • Bydureon (exenatide extended release), taken by injection weekly
  • Trulicity (dulaglutide), taken by injection weekly
  • Ozempic (semaglutide), taken by injection weekly
  • Rybelsus (semaglutide), taken by mouth once daily

GLP-1 agonists are only approved for people who have type 2 diabetes. Because some GLP-1s are taken once a week, it’s important to keep track of when you take your first dose; after that, you should take subsequent doses on the same day. If you miss a dose, there’s usually a “window of opportunity” to make up that missed dose, but you should talk with your doctor or diabetes educator about that. If you wait too long or if you miss several doses, you may need to go back to a lower dose for a while, says Patricia DiPietro, RN, CDCES, at Good Measures.

What are the benefits of taking a GLP-1 agonist?

GLP-1 medications can help people with type 2 diabetes improve their A1C level (a measure of long-term glucose control) by between 0.5% to 1.6%, even in those who take insulin. Along with better glucose control, these medications can help with weight loss — that, in turn, can help improve blood glucose levels. But the benefits don’t stop there — GLP-1 medications can lower the risk of death from heart attack or stroke by as much as 22%. In fact, the American Diabetes Association recommends GLP-1s for people on metformin who have had a heart attack or who are at very high risk for heart disease.

Another benefit of GLP-1s is that they have a low risk of causing hypoglycemia, or low blood glucose. However, if you take GLP-1s with insulin or a sulfonylurea (e.g., glimperide, glyburide, or glipizide), there is a risk of hypoglycemia. The good news is that you may be able to decrease your dose of insulin and/or sulfonylurea (and maybe even stop it altogether) if you take a GLP-1, as well.

What are the side effects of GLP-1 agonists?

Certain side effects can occur with GLP-1 agonists, such as:

  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Bloating
  • Indigestion
  • Headache

It’s common to have some nausea when you first start a GLP-1, as well as if and when you increase the dose. The nausea should be mild, and it generally goes away. But if it’s severe or if you are vomiting, too, you should notify your doctor.

There is also an increased risk of pancreatitis with GLP-1s. People with a history or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2 should not use GLP-1s, nor should people who have gastroparesis or who are on dialysis.

How are GLP-1 agonists administered?

With the exception of Rybelsus, GLP-1s must be given by injection, like insulin. (It’s important to understand that GLP-1s are not insulin and they are often called “non-insulin injectables.”)

These medicines are injected with a pen device, but each GLP-1 has its own, unique pen that is not necessarily like an insulin pen. Some pens, such as the one for Ozempic, are multi-dose pens, whereas the Trulicity pen is a one-dose pen (each pen contains one weekly dose of the medicine). DiPietro advises having a diabetes educator, your provider, or a pharmacist teach you the proper technique for injecting your GLP-1; watching the instruction videos on the manufacturer’s website is also helpful.

Where on the body are GLP-1s injected?

Like insulin, GLP-1s are injected most often in the abdomen, but the upper arm or thighs are acceptable, too. You should change, or rotate, your injection site with each injection (just as you would your insulin injections). Also, if you do take insulin, avoid giving your GLP-1 and insulin injections right next to each other.

GLP-1 agonists and other diabetes medications

GLP-1s can be taken alone, or with other diabetes medicines, such as metformin or sulfonylureas. GLP-1s also come in combination with a basal (long-acting) insulin. These GLP-1 and basal insulin combos are Soliqua or Xultophy, and they’re injected once a day. Ask your doctor if either of these medicines might be right for you, especially if you already take a basal insulin.

Cost of GLP-1s

GLP-1 agonists can be expensive, especially compared to “older” diabetes medications such metformin, sulfonylureas, and some insulins. The cost can be a barrier for some to using this type of medication. Check with your health plan to find out which GLP-1s are covered. Use a website such as to compare prices, and also check the manufacturer’s website for savings cards or coupons. At this time, there are no generic versions of GLP-1s, since they are patent-protected.

Want to learn more about GLP-1 agonists? Read “Non-insulin Injectable Diabetes Medications.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter,, and

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