Understanding GLP-1 side effects

Anyone with type 2 diabetes or who has been trying to lose weight has probably heard of glucagon-like peptide-1 (GLP-1) medications. These treatments can help regulate blood sugar and curb appetite, transforming lives for many people.

Like many medications, GLP-1 medications can have side effects. Whether someone is just starting GLP-1s or has been on them for a while, this guide explains what they might experience and how to help manage those symptoms.

In this article:

What are GLP-1 medications?

For years, GLP-1 medications have been used by health care providers to help manage type 2 diabetes. These medications work by mimicking a natural hormone that helps regulate hunger and blood sugar. In simple terms, these drugs stimulate insulin production — the hormone that lowers blood sugar — and keep levels in a safer, more stable range. They also reduce glucagon release. Glucagon is a hormone that raises blood sugar. By lowering glucagon release, GLP-1 medications help prevent sudden spikes in blood sugar.

Some well-known GLP-1 medications are:

• Dulaglutide injections (common brand name: Trulicity)
• Liraglutide injections (common brand names: Saxenda and Victoza)
• Semaglutide injections (common brand names: Ozempic and Wegovy)
• Semaglutide tablets (common brand names: Ozempic, Rybelsus or Wegovy)
• Orforglipron tablets (common brand name: Foundayo)
• Tirzepatide (GLP-1/GIP receptor agonist) injections (common brand names: Mounjaro and Zepbound)

Over the past few years, some GLP-1 medications have been approved for weight loss. These medications work by increasing feelings of fullness by slowing the rate at which the stomach empties, which can help reduce the urge to overeat. However, it's important to note that not all GLP-1 medications are approved for weight loss, and their side effects can vary.

So, before starting or stopping GLP-1 medications — whether for weight loss or diabetes — it’s important for people to check in with a health care provider. They can give guidance and support to make someone’s GLP-1 journey safe and effective.

Are GLP-1 medications available in pill form?

Semaglutide is a GLP-1 medication that is available in pill form. These medications help to manage type 2 diabetes or reduce weight, and they help to reduce risk of events such as heart attack or stroke in these patients. They work by helping the body release insulin and reduce glucagon production after meals. There are a few options on the market, such as Rybelsus and Wegovy. Other options are also in development.

These two medications can offer benefits such as weight loss or diabetes management, and they also help reduce major cardiovascular events. However, people with a family history of certain thyroid cancers and pancreatitis may need to consider other alternatives. A health care provider can help patients explore options and find the right approach for them.

Common GLP-1 side effects

Some common side effects with GLP-1 medications involve their impact on the digestive system. No matter the reason someone is using these medications, people might experience some gastrointestinal (GI) discomfort, including:

• Constipation
• Diarrhea
• Nausea
• Vomiting

These side effects are most common when people first start treatment or after a recent dosage adjustment. In fact, higher doses of GLP-1 medications in general are more likely to cause these side effects. While these symptoms can be uncomfortable, many symptoms typically subside as the body adjusts to the medication.

That said, it’s important to know when discomfort crosses the line. If side effects are severe, last a long time or feel unusual, it’s best for people to reach out to a health care provider.

Other possible side effects from GLP-1 medications

While not nearly as common, some people may experience other significant side effects with certain GLP-1 medications, such as:

• Cholecystitis. Inflammation of the gallbladder.
• Diabetic eye problems (diabetic retinopathy). Certain GLP-1s can worsen existing retinopathy in people with diabetes.
• Dizziness. Feeling faint or as if the room is spinning.
• Fatigue. Feeling extremely tired or low on energy, which can make everyday tasks more difficult.
• Gallstones (gallbladder disease). Inflammation of the organ or hardened deposits that form in the gallbladder.
• Gastroparesis. Food moves too slowly (or not at all) from the stomach to the small intestine.
• Headache. Pain in any part of the head.
• Increases in heart rate. A rise in resting or baseline heart rate, though changes vary by age and medication.
• Injection site reactions. Itching, redness, rash or other irritation at site where the GLP-1 medication was injected.
• Decreased appetite. Little or no desire to eat.
• Low blood sugar (hypoglycemia). Can intermittently cause low blood sugar, especially if taken with insulin or sulfonylureas; symptoms may include headache, dizziness, shakiness and hunger.
• Pancreatitis. Inflammation of the pancreas, often accompanied by severe abdominal pain.
• Pulmonary aspiration during anesthesia or deep sedation. Food or liquid accidentally enters the lungs while a person is under anesthesia or very deeply sedated.
• Serious allergic reactions (hypersensitivity reaction). Potentially life-threatening. Symptoms may include swelling beneath the skin or trouble breathing.
• Serious kidney problems (acute kidney injury). Sudden kidney failure or worsening of existing kidney conditions.

Potential side effects can vary by product, so always speak to a health care provider with any questions. People should also talk to their health care provider before any planned surgeries or procedures and be prepared to discuss their up-to-date medical history, including a current list of prescribed medications and treatments.

Cosmetic changes from GLP-1s

Since GLP-1 medications can lead to significant weight loss, some people might notice extra or loose skin. That’s because the skin can stretch during weight gain and doesn’t always bounce back fully as elasticity decreases.

Excess skin may show up around the belly area or even the face and can sometimes cause its own issues: This excess skin may feel uncomfortable, make clothes fit awkwardly, lead to irritation and even hygiene challenges.

Cosmetic surgery isn’t medically required, but it may be an option for people who want to remove excess skin after major weight loss.

When to seek immediate medical care for GLP-1 side effects

Most GLP-1 side effects aren’t serious. However, people should contact a health care provider right away if they experience any of the following:

• Difficulty swallowing or breathing
• Intense pain or tenderness in the belly
• Jaundice (yellow skin or eye color)
• Mass in the neck
• Persistent hoarseness
• Severe vomiting or diarrhea
• Vision changes

Key takeaways

Some GLP-1 medications help control blood sugar, and others aid in weight loss. They can cause some side effects, like an upset stomach or diarrhea, and rarely, more serious issues like pancreatitis or thyroid problems. Anyone thinking about taking them or experiencing side effects should consult with a primary care provider or another trusted health care provider to understand the risks.

This article does not cover all information relevant to the use of GLP-1 medications. For questions about GLP-1 medications, speak with a health care provider. GLP-1 prescriptions are based on medical evaluation and are not appropriate for all patients. GLP-1 medications may cause serious side effects. Consult the pharmaceutical packaging of each GLP-1 medication for a complete list of drug interactions, safety information, side effects, warnings and additional information. Insurance coverage for GLP-1 medications varies widely by plan, and some GLP-1 medications may not be covered by insurance.