What is GLP-1?

Glucagon-like peptide-1 (also known as GLP-1) is a type of incretin or gut hormone released by your small intestine whenever you eat.

To some extent, this natural chemical is also produced in the pancreas (pancreatic GLP-1) and your nervous system (brain-derived GLP-1).

Its main role is to regulate your appetite, digestion, and blood sugar while ensuring that you get just enough energy from the food you eat.

Because of its therapeutic effects, pharmaceutical companies have been developing GLP-1 drugs to treat obesity and type 2 diabetes mellitus. 

“There is also increasing interest in the role of GLP-1 in cardioprotection, which is an important subset of the care of diabetic and obese patients,” says our in-house medical expert, Dr. Rizza Mira.

What Does GLP-1 Do?

GLP affects the function of the liver, small intestines, and brain–even at the cellular level. 

GLP-1 triggers the release of the hormone insulin. This is so your body can use the glucose derived from food as an energy source. 

“Insulin is needed for glucose to enter the cells of the body and be utilized for cellular processes,” says Dr. Mira.

At the same time, it inhibits glucagon secretion. Glucagon does the exact opposite of insulin and causes your body to produce more glucose.

GLP-1 also acts as an enterogastrone. It slows the forward movement of the gut and reduces gastric acid secretion once food reaches the small intestine.

Lastly, the metabolic hormone lessens your urge to eat more food by influencing areas of the brain that affect hunger.

What is GLP-1 Medication?

GLP-1 drugs belong to a class of medications that control your blood glucose levels and promote weight reduction.

Other Names for GLP-1 Medications

• Glucagon-like peptide-1 agonists (GLP-1 agonists)
• Glucagon-like peptide-1 receptor agonists (GLP-1 RA)
• Glucagon-like peptide-1 analogs (GLP-1 analogs)

GLP-1 receptor agonists are used to treat diabetes and obesity and can be classified as antidiabetics, anti-obesity drugs, and weight loss medications.

How Does GLP-1 Work?

GLP-1 medications are incretin mimetics that mimic the effects of GLP-1 hormones. They bind with the GLP-1 receptors in your lower gut.

Here’s how they help with glycemic control and weight management:

How GLP-1 Controls Diabetes

People with diabetes have elevated blood sugar because their pancreas doesn’t make enough insulin or they have insulin resistance.

Glucagon-like peptides help with blood glucose control by:

• Stimulating pancreatic β cells. This can stimulate insulin secretion and drive glucose inside the cells to lower blood sugar.
• Stimulating pancreatic α cells. It can inhibit glucagon release and prevent your body from producing more glucose so your levels remain stable.
• Slowing digestion. This prevents sudden increases in glucose concentrations after you eat (also known as postprandial glucose).
• Helping you lose weight. Weight loss increases insulin sensitivity in people whose insulin resistance is caused by too much body weight.

How GLP-1 Causes Weight Loss

Consistently eating more calories than you’re supposed to can lead to weight gain. GLP-1 agonists promote body weight loss in obese patients by:

• Reducing gut motility after eating. Whenever you eat food, GLP-1 slows its passage across your gastrointestinal tract.
• Delaying gastric emptying. Once food reaches your small intestine, the production of gastric juices in your stomach slows down.
• Suppressing appetite. GLP-1 affects areas of the brain that control hunger, so you won’t have the urge to eat often. 

Food that stays longer in the gut can keep you full for extended periods. Since it also reduces your appetite, GLP-1 can decrease your food intake and calories.

GLP-1-containing medications are best taken with a calorie-restricted weight loss diet and regular exercise if you want to lose weight.

Who Can Use GLP-1 Medications?

People with type 2 diabetes (T2DM) or obesity may use GLP-1 drugs prescribed by their doctor. However, doctors may also prescribe them if you:¹

• Are overweight and have at least one weight-related health problem—like high cholesterol levels or high blood pressure—and want to lose weight
• Have T2DM and cardiovascular disease, and want to lower your risk for major cardiovascular events such as acute myocardial infarction or heart attack

Early research suggests that GLP-1 analogs may be used to treat nonalcoholic fatty liver disease (NFLD) and nonalcoholic steatohepatitis (NASH).²

In general, you can take the medication as long as you have a prescription.

What Are Examples of GLP-1 Receptor Agonists? 

GLP-1 agonists are sold under different brand names. Below are some FDA-approved incretin mimetics that are currently available on the market:

• Albiglutide (Tanzeum®, Eperzan®)
• Dulaglutide (Trulicity®)
• Exenatide, Extended Release (Bydureon BCise®)
• Exenatide (Byetta®)
• Liraglutide (Victoza®, Saxenda®)
• Lixisenatide (Adlyxin®)
• Semaglutide (Ozempic®, Wegovy®, Rybelsus®)

Are GLP-1 Drugs Safe?

Yes. Most people can tolerate glucagon-like peptide-1 agonists. Some may experience side effects, although they are usually temporary.

While glucagon-like peptide-1 medicines are safe for most people, they are not suited for everyone. You should inform your doctor if you:

• Are currently taking medications or health supplements
• Have any pre-existing health condition

GLP-1 drugs can be safe for adults, teenagers, or children, depending on the brand. Your doctor will determine which ones are safe for you.

What Are GLP-1 Side Effects?

GLP-1 receptor agonists may cause gastrointestinal side effects at the start of your treatment. This includes nausea, vomiting, and diarrhea.

Other adverse reactions you may experience are headaches, common colds, and skin irritation on the injection site if you’re taking an injectable GLP-1 drug.³

The symptoms you will experience and their severity will depend on your dosage and the brand you’re taking.⁴ For example:

• Nausea and vomiting are generally more common with short-acting GLP-1 drugs like exenatide (Byetta®) and lixisenatide (Adlyxin®).
• Diarrhea tends to be more common with long-acting GLP-1 agonists such as liraglutide (Victoza®, Saxenda®) and exenatide ER (Bydureon BCise®).

The side effects of GLP-1 do not last long and are usually not serious enough to stop treatment. 

“More serious reactions like allergy or symptoms of low blood sugar should prompt you to consult with your doctor,” says Dr. Mira.

What You Need to Know on GLP-1

Here are some things you need to remember about GLP-1 drugs:

Before You Take GLP-1

You shouldn’t take GLP-1 if you’re currently pregnant or breastfeeding, or if you have plans to be pregnant in the following months.

Glucagon-like peptide-1 RAs also shouldn’t be taken if you have a personal or family history of the following medical conditions:

• Diabetic retinopathy
• Gallbladder problems
• Kidney disease
• Multiple endocrine neoplasia 2A or 2B (MEN 2)
• Medullary thyroid cancer
• Pancreatitis
• Pancreatic cancer
• Type 1 diabetes

Inform your doctor if you have other medications or supplements. They can tell you if it’s safe to continue taking them.

Make sure that the GLP-1 prescribed by your doctor doesn’t contain any ingredients you’re allergic to before starting treatment.

What to Avoid on GLP-1

Never take your prescribed GLP-1 drug with insulin treatment and other incretin mimetics. This can cause a significant drop in your blood sugar (hypoglycemia).

To prevent indigestion, you must avoid eating heavy meals and limit your intake of fast food, fried foods, and foods high in sugar and fats.