What is Liraglutide? What it does, benefits and what the evidence shows

Liraglutide is a synthetic GLP-1 receptor agonist, the older, shorter-acting generation of the drug class that later produced semaglutide and tirzepatide. Novo Nordisk sells it as Victoza for type 2 diabetes and as Saxenda for weight management, and it is one of the few compounds in this space with big, published, placebo-controlled trials behind it, including a large cardiovascular outcomes trial. Unlike most of the peptides people buy on the grey market, liraglutide is an approved drug with an FDA label, and since 2024 it also has approved US generics. What the evidence does not tell you is how the vial you might buy outside a pharmacy compares with any of that.

What liraglutide is and how it works

Liraglutide is, in the words of its FDA label, "an acylated human GLP-1 receptor agonist with 97% amino acid sequence homology to endogenous human GLP-1(7-37)" (DailyMed, Victoza label). In plain terms, it is a lightly modified copy of a gut hormone that tells your pancreas to release insulin when blood sugar is high, lowers glucagon, slows how fast the stomach empties, and dampens appetite. The label says it resists breakdown by the enzymes DPP-4 and NEP, which is why it lasts long enough in the body to work as a medicine.

Novo Nordisk markets it under two brand names with different labels. Victoza is the diabetes product. Saxenda is the weight-management product, labeled for adults with obesity, or with overweight plus a weight-related condition, and for adolescents 12 and older who weigh more than 60 kg and have obesity (DailyMed, Saxenda label, revised February 25, 2026). The Victoza label covers adults and children 10 and older with type 2 diabetes (DailyMed, Victoza label, revised October 14, 2025).

It sits in the same family as semaglutide, which is chemically similar, and as tirzepatide, which adds a second gut-hormone target. Liraglutide is the one that came first.

Generics: what is approved in the US

This is the part of the story that changed most recently, and it matters if you are comparing prices.

• June 24, 2024: Teva announced the launch of an authorized generic of Victoza in the US, which the company described as the first generic GLP-1 product available in the country (Teva, June 2024 announcement).
• December 23, 2024: FDA approved Hikma's liraglutide injection, the first generic referencing Victoza, and noted that it prioritizes generic applications for drugs in shortage (FDA announcement). Hikma launched it in the US on December 26, 2024 (Hikma).
• August 28, 2025: Teva announced FDA approval and launch of a generic of Saxenda, which it called the first generic GLP-1 indicated for weight loss (Teva, August 2025 announcement).

We did not find a primary source for any approval beyond those three, and the situation may have moved since, so check the current FDA and DailyMed listings if the specific product matters to you.

What people use it for

What the research actually shows

Type 2 diabetes and heart protection

The heart-protection result is the strongest evidence in the whole liraglutide file. The LEADER trial randomized 9,340 people with type 2 diabetes and high cardiovascular risk to liraglutide or placebo on top of usual care, and followed them for a median of 3.8 years. The primary outcome (cardiovascular death, non-fatal heart attack or non-fatal stroke) occurred in 13.0% of the liraglutide group versus 14.9% of the placebo group, a hazard ratio of 0.87 (95% CI 0.78 to 0.97). Deaths from cardiovascular causes and deaths from any cause were also lower with liraglutide. The most common reasons people stopped the drug were gastrointestinal (Marso et al., NEJM, 2016). That result is why the Victoza label carries a cardiovascular-risk indication for adults with type 2 diabetes and established heart disease (DailyMed).

Worth noticing: this is a diabetes population with existing cardiovascular risk. It does not tell you what liraglutide does for a healthy person using it for weight loss.

Weight loss

The main weight-management trial (SCALE Obesity and Prediabetes) enrolled 3,731 adults without diabetes who had obesity, or overweight with high blood pressure or abnormal cholesterol. Both groups got lifestyle counseling. At week 56, the liraglutide group had lost a mean of 8.4 kg versus 2.8 kg on placebo. About 63% of the liraglutide group lost at least 5% of their body weight (versus 27% on placebo), and 33% lost more than 10% (versus about 11%). The most common side effects were mild or moderate nausea and diarrhea, and serious adverse events were 6.2% with liraglutide versus 5.0% with placebo (Pi-Sunyer et al., NEJM, 2015).

That is a real effect, and it is also the modest end of what this drug class now delivers. In STEP 8, a head-to-head trial in 338 adults with overweight or obesity, semaglutide at its weight-management dose produced a mean weight change of -15.8% versus -6.4% for liraglutide at its own weight-management dose, with about 71% of the semaglutide group losing 10% or more against about 26% on liraglutide. Stopping treatment for any reason was more common on liraglutide (27.6% versus 13.5%), while gastrointestinal side effects were similar in both groups (84.1% and 82.7%) (Rubino et al., JAMA, 2022). The trial was open-label, so participants knew which drug they were on. If you are buying liraglutide because it is older or cheaper, that comparison is the honest trade-off to weigh.

Prediabetes

In a longer follow-up of the same weight-management trial, 2,254 adults with prediabetes were followed for three years. Fewer people on liraglutide were diagnosed with type 2 diabetes (2% versus 6% on placebo), and weight loss at the end was 6.1% versus 1.9%. The authors flag a big caveat: about half the participants had dropped out by the end, and people who withdrew were not followed afterward (Le Roux et al., Lancet, 2017). Delaying diabetes is not a labeled use of Saxenda, so treat this as trial evidence, not an approved claim.

Adolescents

Both labels extend below adulthood. Victoza is labeled from age 10 for type 2 diabetes, based on a placebo-controlled pediatric trial of 134 patients, and Saxenda from age 12 for adolescents above 60 kg with obesity (DailyMed labels, above). We did not open the adolescent obesity trial itself, so we are leaving its numbers out.

Side effects and risks

The labels are blunt and worth reading. Both carry a boxed warning about thyroid C-cell tumors: liraglutide caused them in rodents at clinically relevant exposures, and the human risk is unknown. Both are contraindicated for anyone with a personal or family history of medullary thyroid carcinoma or the genetic syndrome MEN 2. The most common side effects are nausea, diarrhea, vomiting, constipation and decreased appetite. The warnings list includes acute pancreatitis, gallbladder disease, acute kidney injury from dehydration after vomiting or diarrhea, serious allergic reactions, and a risk of aspiration during anesthesia. The Victoza label reports acute gallbladder events in 3.1% of treated patients versus 1.9% on placebo, and the Saxenda label notes a small average rise in heart rate and severe gastrointestinal reactions in 4.8% versus 1.4% on placebo. Saxenda's label also says that using it with any other GLP-1 receptor agonist is not recommended (DailyMed, Victoza; DailyMed, Saxenda).

All of that safety data comes from pharmacy-grade product. The grey-market angle is different and mostly unmeasured: a vial sold as liraglutide has none of the manufacturing controls behind the approved pens, and the failure modes we see across peptides (wrong amount in the vial, low purity, contamination) are the ones that matter most for a drug with this many gastrointestinal side effects. For an injectable that can cause vomiting and dehydration, an unexpectedly strong vial is not a small problem, and a vial with little or no active ingredient means you get the side-effect risk of trying a drug without the benefit. See underdosed peptides and endotoxin in research peptides for what those failures look like in real reports.

What the lab tests show

We have no lab results for liraglutide in the VendorVerify database yet, as of September 29, 2026. That means we cannot tell you how vials sold as liraglutide measure up on purity or on amount versus label, and we will not guess from other GLP-1 compounds. If you have a liraglutide vial tested, you would be adding the first data point: submit your report.

The vendor table below works differently from the compound tables in our other guides. We do not have enough lab data on liraglutide to rank vendors for it, so what follows is the highest-ranked vendors across all compounds right now. A vendor's overall record is a signal, not a guarantee for a compound they have never had tested.

Buying smarter

Because there is no compound-specific record yet, the vendor-level signals matter more. Check how many lab reports sit behind a vendor's score and how recent they are on our vendors page, and ask whether any of them cover a peptide of similar size and type. Treat a posted certificate of analysis as a starting point: how to read a peptide COA and fake peptide COAs cover what to check. The guide to judging a supplier covers the red flags, and the peptide hub lists every compound where we do have results.

Since nobody has published liraglutide results here, testing your own vial is the only way to know what is in it. How to get a peptide tested walks through ordering independent identity, purity and quantity testing. If a report comes back with a fail, stop using that batch, tell anyone who bought from the same run, take the report to the vendor, and submit it to VendorVerify.

Database figures are from VendorVerify as of September 29, 2026; there are none for liraglutide. This isn't medical advice. Liraglutide is an FDA-approved prescription drug as Victoza and Saxenda and as approved generics; vials sold as research peptides are unregulated products.