Side Effects
Understanding the potential side effects of GLP-1 receptor agonist medications.
Common Side Effects
Most side effects are gastrointestinal and tend to improve over time.
Nausea
Very Common (>20%)The most commonly reported side effect, especially during dose escalation. Usually decreases over time as the body adjusts.
Vomiting
Common (10-20%)Often occurs alongside nausea, particularly during the first few weeks of treatment or after dose increases.
Diarrhea
Common (10-20%)Gastrointestinal disturbances including loose stools are common, usually mild to moderate in severity.
Constipation
Common (5-15%)Some patients experience constipation, possibly related to the slowed gastric emptying effect of GLP-1 drugs.
Abdominal Pain
Common (5-15%)Stomach discomfort and cramping, typically mild and often occurring during the initial dosing period.
Decreased Appetite
Very Common (>15%)A therapeutic effect for weight management but classified as a side effect. Most patients experience reduced hunger.
Injection Site Reactions
Common (5-10%)Redness, swelling, or itching at the injection site. Generally mild and resolve on their own.
Headache
Common (5-10%)Mild to moderate headaches are reported, particularly during dose titration phases.
Serious Side Effects
While rare, these serious side effects require immediate medical attention.
Pancreatitis
Inflammation of the pancreas. Patients should stop the medication and seek immediate medical attention if they experience severe, persistent abdominal pain that may radiate to the back.
Thyroid C-Cell Tumors
GLP-1 receptor agonists carry a boxed warning about the risk of thyroid C-cell tumors, based on findings in rodent studies. They are contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Gallbladder Problems
Increased risk of gallstones and cholecystitis (inflammation of the gallbladder), especially with rapid weight loss. Symptoms include sudden, intense pain in the upper right abdomen.
Kidney Problems
Dehydration from nausea, vomiting, or diarrhea can worsen kidney function. Patients with existing kidney disease should be monitored closely.
Hypoglycemia
Low blood sugar is possible, particularly when GLP-1 drugs are combined with insulin or sulfonylureas. Symptoms include shakiness, sweating, confusion, and rapid heartbeat.
Allergic Reactions
Serious allergic reactions, including anaphylaxis, angioedema, and rash, have been reported rarely. Seek emergency care if you experience difficulty breathing, swelling, or severe rash.
Managing Side Effects
Start Low, Go Slow
All GLP-1 drugs use a dose escalation schedule. Starting at a lower dose and gradually increasing helps your body adjust and minimizes GI side effects.
Eat Smaller Meals
Eating smaller, more frequent meals instead of large ones can help reduce nausea and discomfort.
Stay Hydrated
Drink plenty of water, especially if experiencing vomiting or diarrhea, to prevent dehydration and kidney complications.
Avoid Trigger Foods
Fatty, greasy, or spicy foods may worsen GI symptoms. Bland, easy-to-digest foods may be better tolerated during dose escalation.
Medical Disclaimer
This is not an exhaustive list of side effects. Individual experiences may vary. If you experience any concerning symptoms while taking a GLP-1 medication, contact your healthcare provider immediately. Do not stop taking your medication without consulting your doctor.