Liraglutide

What it is

Liraglutide is a GLP-1 receptor agonist sold as Saxenda for weight loss and Victoza for diabetes. GLP-1 is a hormone the gut naturally releases after eating; liraglutide is a synthetic version that activates the same receptor. It is an earlier GLP-1 medicine than semaglutide and has a shorter half-life (the time the body takes to clear half of a dose).

In the PeptidesAI encyclopedia, liraglutide is categorized under weight management. Alongside the branded pre-filled pens, lyophilized (freeze-dried) liraglutide powder in vials is also sold as a research product, which is a separate thing from the approved pens.

How it's thought to work

Liraglutide is a GLP-1 receptor agonist. Research describes GLP-1 receptor activation as suppressing appetite, slowing gastric emptying (the rate at which food leaves the stomach), and enhancing glucose-dependent insulin secretion, meaning insulin release that follows blood sugar.

What the research says

The SCALE trials supported FDA approval of liraglutide as Saxenda for chronic weight management. In a 56-week trial of 3,731 adults without type 2 diabetes, 63.2% of participants on liraglutide lost at least 5% of their body weight, compared with 27.1% on placebo.

Liraglutide is also FDA-approved as Victoza, as an adjunct to diet and exercise to improve glycemic control in patients 10 years and older with type 2 diabetes and to reduce the risk of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease.

Reported side effects

The Saxenda label lists nausea, diarrhea, constipation, vomiting, injection site reactions and headache among the most common adverse reactions (those reported in at least 5% of patients). In the 56-week SCALE trial, the most frequently reported adverse events were mild or moderate nausea and diarrhea.

The label also describes acute pancreatitis as a warning, and carries a boxed warning for thyroid C-cell tumors, which liraglutide caused in rats and mice. It is unknown whether liraglutide causes thyroid C-cell tumors in humans.

Reconstitution

The branded pens sold as Saxenda and Victoza come pre-filled and ready to use; they are not reconstituted by the patient. This page instead covers lyophilized (freeze-dried) liraglutide powder sold in 5 mg vials, which is typically reconstituted with bacteriostatic (BAC) water before use.

Worked example. A 5 mg vial is 5,000 mcg. Reconstituted with 1 mL of BAC water, that works out to 5,000 mcg ÷ 1 mL = 5,000 mcg/mL. On a U-100 insulin syringe, where each unit is 0.01 mL, each unit holds 5,000 × 0.01 = 50 mcg. Use the peptide reconstitution calculator to work out the concentration and units for any vial size and water volume.

Important notes

Liraglutide is an FDA-approved prescription medicine, sold as Saxenda and Victoza. The lyophilized vials discussed on this page are research-grade powder, a separate product from the branded, ready-to-use pens, and are not themselves FDA-approved products.

Sources

1. A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management.. Pi-Sunyer X et al. N Engl J Med, 2015. Human trial
2. Glucagon-like peptide 1 (GLP-1). Müller TD et al. Molecular Metabolism, 2019. Review
3. SAXENDA (liraglutide) injection, for subcutaneous use - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2026. Fda label
4. VICTOZA (liraglutide) injection, for subcutaneous use - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2025. Fda label

How we choose and check sources

Frequently asked questions

These questions cover the same ground as the sections above, in a shorter format.

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