Liraglutide is a prescription medication used for the chronic management of body weight in adults and some adolescents. It is marketed under the brand name Saxenda for weight loss and Victoza for type 2 diabetes, though both contain the same active ingredient. This drug belongs to a class of compounds known as glucagon-like peptide-1 (GLP-1) receptor agonists. Liraglutide is administered as an adjunct to a reduced-calorie diet and increased physical activity.
How Liraglutide Promotes Weight Loss
Liraglutide works by mimicking the action of glucagon-like peptide-1, which is a naturally occurring hormone released by the intestines after food consumption. This synthetic version binds to and activates GLP-1 receptors found in various parts of the body, particularly in the brain and the digestive tract. By acting on these receptors, liraglutide helps to regulate appetite and caloric intake.
One of the drug’s primary mechanisms involves signaling the appetite control centers in the brain, specifically the hypothalamus. When activated, the GLP-1 receptors in this region promote a feeling of fullness, known as satiety, while simultaneously reducing the sensation of hunger. This central action leads directly to a reduced desire to eat and a decrease in overall food consumption.
Additionally, liraglutide affects the speed at which the stomach empties its contents into the small intestine, a process called gastric emptying. By slowing this process, the medication contributes to the feeling of being full for a longer duration after a meal. This delayed gastric transit means nutrients are absorbed more gradually, which further supports a lower daily caloric intake necessary for weight reduction.
The Standard Treatment Protocol
Liraglutide is self-administered as a daily subcutaneous injection, typically in the abdomen, thigh, or upper arm. It can be taken at any time of day, with or without regard to meals, but is most effective when administered around the same time each day to maintain consistent drug levels. The medication is dispensed in a pre-filled pen device, which simplifies the process for patients managing their treatment at home.
A necessary element of the treatment protocol is a dose escalation, or titration, period that lasts several weeks. Treatment begins at a low starting dose of 0.6 milligrams (mg) once daily, which is gradually increased each week. The dose is typically raised by 0.6 mg increments until the full therapeutic dose of 3.0 mg per day is reached, usually by the fifth week of treatment.
Titrating the dose helps to mitigate the gastrointestinal side effects that are common when beginning therapy. For the drug to be effective, it must be used consistently alongside a comprehensive lifestyle modification program that includes a reduced-calorie diet and a regimen of increased physical activity.
Typical Weight Loss Results and Patient Criteria
Liraglutide is prescribed for adults who meet specific clinical criteria based on their Body Mass Index (BMI). An individual generally qualifies if they have a BMI of 30 kg/m² or greater, which is categorized as obesity. Alternatively, the medication may be prescribed to adults with a BMI of 27 kg/m² or greater if they also have at least one weight-related comorbidity, such as hypertension, dyslipidemia, or type 2 diabetes.
Clinical trials, known as the SCALE studies, have demonstrated the drug’s effectiveness when used in combination with lifestyle changes over a 56-week period. In one major trial, individuals receiving the 3.0 mg dose of liraglutide achieved an average body weight loss of approximately 5 to 6 percent from their baseline weight. This result was significantly higher than the weight loss observed in the placebo group, which only received lifestyle counseling.
Roughly half of the patients treated with liraglutide were able to achieve a clinically meaningful weight loss of 5 percent or more of their initial body weight. Furthermore, about one-quarter of the participants lost 10 percent or more of their body weight during the trial period.
Common Side Effects and Safety Warnings
The most frequently reported side effects associated with liraglutide are related to the gastrointestinal system. These effects include nausea, vomiting, diarrhea, and constipation, which are often most pronounced during the initial dose titration phase. These symptoms tend to decrease in severity over time as the body adapts to the drug.
Serious safety warnings are associated with the use of liraglutide. The medication carries a Boxed Warning regarding the risk of thyroid C-cell tumors, which were observed in rodent studies. For this reason, liraglutide is not to be used by individuals with a personal or family history of Medullary Thyroid Carcinoma (MTC).
The drug is also contraindicated for patients diagnosed with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), a genetic condition that predisposes individuals to MTC. Other serious, though less common, adverse events include the risk of acute pancreatitis, which is characterized by severe, persistent abdominal pain. Patients also have an increased potential for developing gallbladder issues, such as cholelithiasis or cholecystitis, which may necessitate surgical intervention.