The Weight Loss Drug Saxenda (Liraglutide)

On December 23, 2014, the U.S. Food and Drug Administration (FDA) approved liraglutide as a treatment option for chronic weight management. Liraglutide is being marketed by Novo Nordisk, Inc., under the brand name Saxenda®. This is the fourth drug for weight loss that has been approved by the FDA since 2012.

A nurse filling a syringe for a patient
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What Is Saxenda (Liraglutide)?

Saxenda® is an injection that is already available in a lower dose as another drug, Victoza®, which in turn is used for the treatment of type 2 diabetes. It belongs to a class of drugs known biochemically as glucagon-like peptide-1 (GLP-1) receptor agonists. Another drug in this class includes exenatide (Byetta®). While all are used for diabetes, liraglutide (in its higher dose as Saxenda®) is the first to receive FDA approval specifically for weight management.

For Whom Is Saxenda Intended?

Saxenda® has been approved for use in adults with a body mass index (BMI) of 30 or greater, or in adults with a BMI of 27 or greater who have at least one other weight-related disorder, such as diabetes, high blood pressure, or high cholesterol.

BMI is a dated, flawed measure. It does not take into account factors such as body composition, ethnicity, sex, race, and age. 

Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.

In addition, Saxenda® is meant to be used as an adjunct to diet and exercise for chronic weight management in adults. It is not meant to replace diet and exercise.

How Effective Is It?

Three clinical trials have evaluated the safety and effectiveness of Saxenda®. These trials enrolled approximately 4,800 obese and overweight patients in total. One clinical trial that examined patients without diabetes found an average weight loss of 4.5% in the patients who took Saxenda®. This trial also found that 62% of those who were treated with Saxenda® lost at least 5% of their body weight.

In another clinical trial that looked at patients with type 2 diabetes, results showed that those treated with Saxenda® lost 3.7% of their weight compared to treatment with placebo, and 49% of those taking Saxenda® lost at least 5% of their body weight (compared to only 16% of those taking placebo).

Thus, it appears that Saxenda® may be slightly more effective for weight loss in patients who do not have type 2 diabetes, although it still had an effect — albeit a smaller one — on weight management for those with diabetes.

What Are the Side Effects?

The FDA has issued a black box warning on Saxenda®, stating that tumors of the thyroid gland have been observed in studies on rodents, but that it is unknown whether or not Saxenda® can cause these tumors in humans.

Serious side effects that have been reported in patients taking Saxenda® include pancreatitis (inflammation of the pancreas, which can be life-threatening), gallbladder disease, kidney disease, and suicidal thoughts. Additionally, Saxenda® can raise heart rate, and the FDA advises that it is being discontinued in any patient who experiences a sustained increase in resting heart rate.

The most common side effects of Saxenda® that were seen in the clinical trials were nausea, constipation, vomiting, diarrhea, decreased appetite, and low blood sugar (hypoglycemia).

Who Should Not Take Saxenda?

Due to the theoretical risk of thyroid tumors, Saxenda® should not be taken by patients who have a rare endocrine disorder known as multiple endocrine neoplasia syndrome type 2 (MEN-2), or by patients who have a personal or family history of a type of thyroid cancer known as medullary thyroid carcinoma (MTC).

Others who should not take Saxenda® include children (the FDA is currently requiring clinical trials to evaluate the safety and efficacy in children), women who are pregnant or breastfeeding, and anyone who has ever had a serious hypersensitivity reaction to liraglutide or to any of the product components of Saxenda®.

Other Concerns

According to the FDA news release regarding its approval of Saxenda®, the agency is requiring the following post-marketing studies for this medication:

  • Clinical trials to evaluate safety, efficacy, and dosing in children;
  • A case registry of medullary thyroid cancer of at least 15 years’ duration;
  • A study to evaluate potential effects on growth, central nervous system development and sexual maturation in immature rats; and
  • An assessment of the potential risk of breast cancer in patients taking Saxenda® in ongoing clinical trials.
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  • FDA news release. FDA approves weight-management drug Saxenda.
  • Saxenda prescribing information. Novo Nordisk.

By Yasmine S. Ali, MD, MSCI
Yasmine Ali, MD, is board-certified in cardiology. She is an assistant clinical professor of medicine at Vanderbilt University School of Medicine and an award-winning physician writer.