Liraglutide is a modified form of glucagon-like peptide-1 (GLP-1) used in approved medicines for type 2 diabetes and long-term weight management. It helped establish that extending the action of a gut hormone could improve glucose control, reduce weight and change cardiovascular outcomes in selected patients. Its evidence also includes studies that found no benefit in advanced heart failure and a small liver-biopsy trial. Reading those results together shows why the disease setting matters as much as the hormone pathway.
Overview
Molecular profile
- Type
- Modified GLP-1 peptide analogue; 31 amino acids Source
- Chemical form
- Liraglutide active peptide in approved injection formulations Source
- Molecular formula
- C172H265N43O51 (liraglutide active peptide) Source
- Molecular weight
- 3751.2 Da (liraglutide active peptide) Source
- Structural modifications
- Arg34 substitution and a C16 (16-carbon) fatty-acid attachment through a glutamic-acid spacer at Lys26 Source
- Primary target
- GLP-1 receptor Source
Forms and derivatives
Victoza
Liraglutide's diabetes product is approved for glucose control from age ten and cardiovascular-event risk reduction in adults with type 2 diabetes and established cardiovascular disease.
Saxenda
The weight-management formulation contains the same active liraglutide peptide and has adult and qualifying adolescent indications.
Human GLP-1 is a meal-related hormone that is rapidly broken down in the circulation. Liraglutide attaches a fatty-acid chain to a GLP-1 analogue, encouraging association with albumin and delaying its disappearance. Early investigators called the molecule NN2211. Agersø and colleagues (2002) studied its pharmacokinetics and pharmacodynamics in healthy men and established prolonged exposure after subcutaneous administration.
Victoza and Saxenda contain liraglutide but were developed for different clinical uses and treatment contexts. Product identity includes the active peptide and its pharmaceutical formulation. The clinical studies summarized here identify those preparations and their populations; a formulation containing another peptide or an added ingredient brings additional evidence requirements. Close variants are recorded within this profile so the active molecule's identity remains traceable.
Uses and research areas
The current Victoza label, revised October 2025 and checked in October 2026, covers glucose control in adults and children aged 10 years or older with type 2 diabetes. It also covers reduction of major cardiovascular events in adults with type 2 diabetes and established cardiovascular disease. Saxenda's February 2026 label covers long-term weight management in adults and adolescents aged 12 years or older with obesity and body weight greater than 60 kg, and adults with overweight plus a weight-related condition.
The SCALE programme examined weight loss and progression from prediabetes to diabetes. LEADER measured cardiovascular events, FIGHT examined clinical stability after hospitalization for reduced-ejection-fraction heart failure, and LEAN examined liver histology in steatohepatitis. These studies extend understanding of liraglutide, while the current US labels retain their defined diabetes, cardiovascular and weight-management indications.
Mechanism of action
GLP-1 receptors help translate a nutrient signal into pancreatic hormone release. In insulin-producing beta cells, activation strengthens glucose-dependent insulin secretion. Liraglutide also suppresses inappropriate glucagon secretion, reducing the signal for the liver to release glucose. These effects become more relevant as glucose rises. They explain how a GLP-1 analogue can improve glucose control while the risk of hypoglycemia remains strongly influenced by concurrent insulin or medicines that stimulate insulin release. Section 12.1 of the Victoza prescribing information describes this pancreatic response.
The appetite effect brings the gut and brain into the same explanation. Liraglutide influences GLP-1 receptor pathways involved in food intake and slows gastric emptying, which changes the movement of nutrients into the intestine. Lower energy intake can then reduce body weight over time. The Saxenda label, section 12.1 places weight regulation in this physiological context. Cardiovascular and liver findings require additional interpretation because changes in metabolism, body weight and disease burden unfold together during treatment.
Pharmacokinetics
Fatty-acid attachment changes both absorption and distribution. Liraglutide molecules can associate with one another at the administration site, slowing entry into blood, and albumin binding helps protect the circulating peptide from rapid breakdown. The drug is then metabolized as a peptide. The Saxenda label, sections 11–12.3 describes this combination of delayed absorption, protein binding and resistance to enzymatic degradation.
In the early human NN2211 study, Agersø and colleagues (2002) assessed 84-hour pharmacokinetic profiles after subcutaneous administration, including repeated exposure over seven days. The reported half-life was 12.6 ± 1.1 hours. Current product labeling summarizes an elimination half-life of approximately 13 hours. The early value and the later label agree on persistence over hours, while semaglutide's elimination extends over days.
Population: Human participants characterized after subcutaneous liraglutide administration in product pharmacokinetics. Administration: subcutaneous administration; illustration begins in the post-absorption elimination phase. Analyte: circulating liraglutide parent peptide.
The product label reports an approximate human elimination half-life of 13 hours. This calculated curve shows what repeated halving at that rate would look like after absorption: 50% of an arbitrary starting concentration remains after 13 hours. The plotted values are an illustration, not measured patient blood concentrations. The figure applies C/C0 = 2^(-t/t_half) with constant first-order elimination after absorption. Its starting value is arbitrary and represents a percentage, not a blood concentration. Delayed absorption, distribution transients, repeated administration and between-person variability are outside the modeled phase.
Novo Nordisk. SAXENDA (liraglutide) injection: US prescribing information. Revised February 2026; DailyMed updated February 25, 2026. SAXENDA section 12.3, Metabolism/Elimination: approximate human half-life 13 hours; consistent with early NN2211 study.
The illustration uses the label's approximate 13-hour elimination half-life and begins at an arbitrary normalized concentration after absorption. Its curve shows the mathematical consequence of that half-life. It leaves the rising absorption phase and real interindividual concentration differences unspecified, so it cannot identify a clinical peak or the duration of a particular effect.
Research findings
Weight management and progression to diabetes
Pi-Sunyer and colleagues (2015) randomized 3,731 adults without type 2 diabetes to liraglutide or placebo alongside lifestyle support. Participants had obesity, or qualifying overweight with dyslipidemia or hypertension. At 56 weeks, mean weight loss was 8.4 kg with liraglutide and 2.8 kg with placebo; 63.2% and 27.1%, respectively, lost at least 5% of starting weight. The trial measured a sustained difference during the treatment period and established an evidence base for weight management.
The longer SCALE analysis by le Roux and colleagues (2017) followed adults with prediabetes for up to 160 weeks. Among treated participants, diabetes was diagnosed during treatment in 26 of 1,472 receiving liraglutide and 46 of 738 receiving placebo. The time-to-diagnosis hazard ratio was 0.21, while mean weight changes were −6.1% and −1.9%. Only half of the randomized participants completed follow-up, and participants who withdrew were not followed after discontinuation. The observed delay therefore describes the followed treatment population; it leaves the durability of diabetes prevention after treatment unresolved.
Cardiovascular events and advanced heart failure
Marso and colleagues' LEADER trial (2016) enrolled 9,340 people with type 2 diabetes and high cardiovascular risk, with liraglutide or placebo added to usual care. Over a median 3.8 years, cardiovascular death, nonfatal myocardial infarction or nonfatal stroke occurred in 13.0% versus 14.9%, hazard ratio 0.87. Heart-failure hospitalization was not significantly reduced. The result supports the cardiovascular use of liraglutide in a defined diabetes population while preserving the outcome-specific findings.
Margulies and colleagues' FIGHT trial (2016) studied 300 adults recently hospitalized with heart failure and reduced ejection fraction; 59% had type 2 diabetes. To assess clinical stability over 180 days, investigators ranked participants using deaths, heart-failure rehospitalizations and changes in NT-proBNP, a blood marker of cardiac stress. The combined ranking did not establish an improvement with liraglutide: mean ranks were 146 with liraglutide and 156 with placebo (P=0.31). Heart-failure rehospitalization occurred in 41% versus 34%; that difference was statistically uncertain. The authors also reported kidney-function findings that raised safety concerns. This small trial was not designed to give a reliable comparison of safety risks, but its results make the recently hospitalized heart-failure population a separate concern from LEADER's broader cardiovascular-risk population.
A small liver-biopsy study
Armstrong and colleagues' LEAN trial (2016) randomized 52 overweight adults with biopsy-confirmed nonalcoholic steatohepatitis, now generally termed MASH. After 48 weeks, steatohepatitis resolved without worsening fibrosis in 9 of 23 participants with an end-of-treatment biopsy in the liraglutide group and 2 of 22 in the placebo group. The relative risk was 4.3, with a wide 95% confidence interval of 1.0–17.7. The biopsy result gave a reason for larger liver studies across the GLP-1 class. The small sample and biopsy denominators limit precision about liraglutide's liver effect, and neither current US product label includes MASH treatment.
Safety and tolerability
Gastrointestinal symptoms, especially nausea, vomiting and diarrhea, are common. Important concerns include pancreatitis, gallbladder disease, dehydration-associated kidney injury, increased heart rate and serious hypersensitivity. The current Victoza label also addresses severe gastrointestinal reactions, hypoglycemia with insulin or secretagogues, and aspiration during anesthesia or deep sedation. Slower gastric emptying provides the physiological link between gastrointestinal effects and procedural risk.
The boxed warning concerns thyroid C-cell tumors in rodents, with uncertain human relevance. Contraindications include personal or family medullary thyroid carcinoma, multiple endocrine neoplasia type 2 (MEN2) and serious hypersensitivity. Pregnancy is a fetal-risk concern for weight management. Saxenda's February 2026 label records removal of the earlier suicidal-behavior warning. Tolerability, disease context and background medications remain central to assessing the trial findings.
What the research means
Liraglutide's development established several lasting findings: extended GLP-1 activity can lower glucose and weight, and cardiovascular benefits can be demonstrated by measuring events over years. Its research also shows the value of testing plausible uses separately. LEADER's event reduction, FIGHT's neutral clinical-stability result and LEAN's preliminary biopsy improvement each belong to a different population and endpoint.
The longer SCALE result raises a maintenance question similar to that seen with later obesity medicines. A lower rate of diabetes diagnosis during followed treatment is clinically meaningful, while the absence of continued observation after withdrawal limits claims about permanent prevention. This distinction gives a more useful interpretation than treating all metabolic changes as interchangeable evidence of long-term disease reversal.
FAQs
Why did LEADER and FIGHT produce different heart-related findings?
LEADER studied cardiovascular events over years in people with type 2 diabetes at high cardiovascular risk. FIGHT studied clinical stability soon after hospitalization for advanced heart failure with reduced ejection fraction. Their populations and endpoints differ substantially, so the positive LEADER result cannot determine the FIGHT result.
Did the three-year SCALE analysis show permanent diabetes prevention?
The followed treatment population had fewer diabetes diagnoses. Only half the randomized participants completed the study, and people who withdrew were not followed after discontinuation. The result establishes a delay during that observed treatment context, while persistence after stopping remains unresolved. le Roux and colleagues (2017) describe those limits.
What did the LEAN liver study contribute?
The small randomized study found more participants with resolution of steatohepatitis on their final biopsy. The wide confidence interval and incomplete final biopsies limit precision. It helped justify larger liver programmes across the GLP-1 class; liraglutide's current US labels do not include MASH treatment.
What is the relationship between NN2211 and liraglutide?
NN2211 was the development name used in early liraglutide studies. The healthy-men pharmacokinetic paper used that name and measured prolonged exposure after subcutaneous administration. The current product labels describe the same active peptide with its approved product names.
Comparisons and related reading
Semaglutide shares GLP-1 receptor activity but has longer persistence and a different set of formulation-specific outcome trials. Tirzepatide combines GIP and GLP-1 receptor activity. Pramlintide engages the amylin pathway and was developed as an adjunct to mealtime insulin. These connections help readers compare biological strategies while keeping the direct clinical evidence for each molecule visible.
References
This current listing defines diabetes treatment from age ten, adult cardiovascular use with established disease, and product safety and pancreatic effects.
- Novo Nordisk. SAXENDA (liraglutide) injection: US prescribing information. Revised February 2026; DailyMed updated February 25, 2026. · dailymed.nlm.nih.gov
The weight-management label supplies liraglutide identity and an approximate 13-hour half-life, and records removal of the earlier suicidal-behavior warning.
An early liraglutide study measured 84-hour profiles in healthy men and reported a 12.6 ± 1.1-hour half-life.
The 56-week SCALE trial establishes weight-management evidence in adults without diabetes, with lifestyle support in both groups.
The longer SCALE follow-up measures diabetes diagnoses during treatment and identifies substantial attrition and absent follow-up after withdrawal.
LEADER compared liraglutide with placebo in people with type 2 diabetes at high cardiovascular risk. It found fewer major cardiovascular events, while the heart-failure hospitalization comparison remained uncertain.
- Margulies KB, Hernandez AF, Redfield MM, et al. (2016). Effects of Liraglutide on Clinical Stability Among Patients With Advanced Heart Failure and Reduced Ejection Fraction: A Randomized Clinical Trial. JAMA 316(5):500–508. DOI: 10.1001/jama.2016.10260. · Full text (PMC)
FIGHT found no clinical-stability benefit after advanced-heart-failure hospitalization and describes exploratory rehospitalization and renal safety signals.
LEAN supplies a small randomized biopsy comparison in steatohepatitis, with wide uncertainty and seven missing end-of-treatment biopsies.
Glossary
- GLP-1
- Glucagon-like peptide-1, a gut hormone involved in meal-related glucose regulation and appetite.
- Albumin
- A blood protein whose binding helps prolong exposure to liraglutide.
- HbA1c
- Glycated hemoglobin, a measure reflecting average blood glucose over the preceding months.
- Prediabetes
- Glucose regulation above the normal range but below the diagnostic range for diabetes.
- Ejection fraction
- The percentage of blood in a ventricle pumped out with each contraction.
- NT-proBNP
- A blood marker associated with cardiac wall stress, included in FIGHT's clinical-stability assessment.
- Fibrosis
- Scar-tissue accumulation in an organ such as the liver.
- Attrition
- Loss of participants from a study; who remains affects the interpretation of follow-up results.