Liraglutide: evidence, FDA status and research

It is a daily injection for type 2 diabetes and for weight loss. Large trials of 9,340 and 3,731 people showed fewer heart problems and about 8% weight loss.

Sold for

Liraglutide was the first daily GLP-1 drug to be approved for weight loss and is now marketed as the cheaper generic alternative to semaglutide for people who want a GLP-1 but cannot get or afford the newer ones.

Studies say

Trials in nearly 10,000 diabetic patients and 3,700 adults with obesity showed fewer heart events and about 8 percent body weight loss respectively, which earns an A for both approved uses.

Why grade A. Both uses rest on large randomized placebo-controlled trials: LEADER (9,340 patients with type 2 diabetes, cardiovascular outcomes) and the SCALE obesity trial (3,731 adults, 56 weeks of weight loss). Multiple other phase 3 trials sit behind the labels. What the citations do not cover is how liraglutide compares with the newer weekly GLP-1 drugs, which outperform it on weight. ⁴⁶

FDA. Approved. Liraglutide is sold as Victoza (approved 2010) for type 2 diabetes in adults and children aged 10 and older and to reduce major cardiovascular events in adults with type 2 diabetes and heart disease, and as Saxenda (approved 2014) for chronic weight management in adults and adolescents aged 12 and older. Generic liraglutide for both indications has been approved since December 2024 and August 2025. ¹²⁵

Written from 7 cited sources. Fact-checked 2026-10-27: 20 claims checked, 0 corrected. Last refreshed 2026-10-27. Not physician reviewed.

What this means for you

What people take it for: Type 2 diabetes, weight loss, heart protection
Can a US doctor prescribe it?: Yes, FDA approved for type 2 diabetes and for long-term weight management.
Properly tested in people?: Yes, in large controlled trials of 9,340 and 3,731 people.

Evidence checklist

Randomised controlled trial LEADER and SCALE, placebo-controlledyes
Human study over 100 people LEADER 9,340; SCALE 3,731yes
More than one research group Multiple phase 3 trials behind both labelsyes
Clinical outcomes, not surrogate markers LEADER: fewer heart attacks, strokes, deathsyes
Human safety data beyond case reports Years of trial data; boxed thyroid warningyes

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Liraglutide is a modified version of human glucagon-like peptide-1 (GLP-1), a gut hormone released after meals. One amino acid is swapped and a fatty acid chain is attached, which lets the molecule bind albumin in the blood and survive about 13 hours instead of the two minutes of the natural hormone. Novo Nordisk developed it as the first long-acting GLP-1 receptor agonist suitable for daily injection. ¹³

Two brands carry different indications. Victoza is for type 2 diabetes and, since 2017, for reducing heart attack, stroke, and cardiovascular death in diabetic adults with established heart disease. Saxenda, a higher-dose presentation, is for chronic weight management alongside diet and exercise. Both are now also approved for adolescents, and generics of each exist. ¹²⁵

How it works

Liraglutide activates the GLP-1 receptor. In the pancreas that increases insulin release when glucose is high and suppresses glucagon, so blood sugar falls without much hypoglycemia risk on its own. It also slows stomach emptying. ¹

The weight effect comes mostly from the brain. GLP-1 receptors in the hypothalamus and brainstem regulate appetite, and liraglutide reduces hunger and increases fullness, so people eat less. The Saxenda label describes this action on appetite centers as the proposed basis for weight loss. ⁵

What human research shows

LEADER randomized 9,340 adults with type 2 diabetes at high cardiovascular risk to liraglutide or placebo and followed them for a median of 3.8 years. The composite of cardiovascular death, heart attack, or stroke occurred in 13.0 percent on liraglutide versus 14.9 percent on placebo, a 13 percent relative reduction, with cardiovascular death itself down 22 percent. This trial underpins the cardiovascular indication. ⁴

The SCALE Obesity and Prediabetes trial randomized 3,731 adults without diabetes to liraglutide or placebo for 56 weeks with lifestyle counseling. Mean weight loss was 8.0 percent on liraglutide versus 2.6 percent on placebo; 63 percent versus 27 percent lost at least 5 percent of their weight. ⁶

A blinded randomized trial from Uppsala tested whether liraglutide could preserve the remaining insulin-producing cells in 18 adults who had had type 1 diabetes for at least five years and still had detectable C-peptide. After 52 weeks there was no difference from placebo in stimulated C-peptide. An exploratory analysis running to week 65 found a steeper decline on liraglutide with rising insulin requirements. The trial is small and the decline signal is post hoc, but the result argues against liraglutide as a beta-cell protector in long-standing type 1 diabetes. ⁷

Study	Model	Finding
LEADER (Marso 2016)	Humans, n=9,340 with type 2 diabetes, randomized double-blind placebo-controlled, median 3.8 years	Major cardiovascular events fell from 14.9 to 13.0 percent and cardiovascular death fell 22 percent with liraglutide. ⁴
SCALE Obesity and Prediabetes (Pi-Sunyer 2015)	Humans, n=3,731 adults with obesity, randomized double-blind placebo-controlled, 56 weeks	8.0 percent mean weight loss on liraglutide versus 2.6 percent on placebo. ⁶
Victoza prescribing information	FDA label (2025 revision)	Glycemic lowering in adults and children aged 10 and older, cardiovascular risk reduction, boxed thyroid C-cell warning. ¹
Uppsala type 1 diabetes trial (2026)	Humans, n=18 adults with long-standing type 1 diabetes, randomized blinded placebo-controlled, 52 weeks	No preservation of stimulated C-peptide; exploratory analysis suggested a faster decline on liraglutide. ⁷

Safety

Nausea, vomiting, diarrhea, and constipation are the most common side effects and the main reason people stop. In SCALE, gastrointestinal events were the leading cause of discontinuation. Gallbladder disease, pancreatitis, and faster heart rate are listed warnings. ⁵⁶

Both labels carry a boxed warning about thyroid C-cell tumors seen in rodents; liraglutide is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2. Whether the rodent finding applies to humans is unknown after more than a decade of use. Hypoglycemia becomes a concern when liraglutide is combined with insulin or sulfonylureas. ¹⁵

Questions for your clinician

How does liraglutide compare with newer weekly GLP-1 drugs for my goals?
What should I know about the thyroid tumor warning given my family history?
What helps if nausea becomes a reason to stop?

Questions people ask

Is liraglutide the same as semaglutide?

Both are GLP-1 receptor agonists from Novo Nordisk, but liraglutide is a daily injection and produces less weight loss than weekly semaglutide in trials. Liraglutide has been generic since 2024, which is why it has become the lower-cost option. ²³

What is the difference between Victoza and Saxenda?

Same molecule, different doses and indications. Victoza is labeled for type 2 diabetes and cardiovascular risk reduction; Saxenda is labeled for chronic weight management. ¹⁵

How much weight do people lose on liraglutide?

In the largest trial, 3,731 adults lost an average of 8 percent of body weight over 56 weeks, compared with 2.6 percent on placebo with the same diet and exercise advice. ⁶

Does liraglutide protect the heart?

In LEADER, 9,340 diabetic patients at high risk had 13 percent fewer major cardiovascular events over about four years. That result applies to people with type 2 diabetes and heart disease, the population studied. ⁴

What is the thyroid warning about?

Liraglutide caused thyroid C-cell tumors in rats and mice. The human relevance is unknown, so the label contraindicates it in people with a history of medullary thyroid cancer or MEN 2. ¹

Citations

FDA 2025: Victoza (liraglutide) prescribing information accessdata.fda.gov
Drugs.com: Liraglutide monograph and generic availability drugs.com
2025, Pharmacological Research: Review of liraglutide development and pharmacology sciencedirect.com
Marso 2016, NEJM: Liraglutide and cardiovascular outcomes in type 2 diabetes (LEADER) doi.org
FDA 2025: Saxenda (liraglutide) prescribing information accessdata.fda.gov
Pi-Sunyer 2015, NEJM: A randomized controlled trial of liraglutide for weight management (SCALE) doi.org
Caballero-Corbalán 2026, Diabetes Obes Metab: liraglutide and beta-cell function in long-standing type 1 diabetes, blinded randomized trial pubmed.ncbi.nlm.nih.gov

Updates

2026-10-27 added blinded RCT in 18 adults with long-standing type 1 diabetes, no C-peptide preservation and a possible faster decline (PMID 42595732) to human findings and key studies.