Liraglutide: Uses, Doses, Side Effects, and How It Compares to Semaglutide and Tirzepatide

What is liraglutide and how does it work?

Liraglutide is an acylated human GLP-1 receptor agonist with 97% amino acid sequence homology to endogenous GLP-1(7-37). It is stable against DPP-4 and neutral endopeptidase degradation and has a plasma half-life of about 13 hours after subcutaneous injection, and it is given once daily [1]. GLP-1 is a physiological regulator of appetite and calorie intake, and GLP-1 receptors are present in brain areas involved in appetite regulation; liraglutide also delays gastric emptying [1].

What is liraglutide approved for?

Two Novo Nordisk products contain liraglutide, each with its own FDA approval and label.

Saxenda (label effective 2026-02-25), with a reduced-calorie diet and more physical activity, is approved to reduce excess body weight and maintain weight reduction long term in adults and children aged 12 and older with body weight above 60 kg and obesity, and in adults with overweight plus at least one weight-related comorbid condition. The label says not to combine it with another liraglutide product or any other GLP-1 receptor agonist [1].

Victoza (label effective 2025-10-14) is approved to improve glycemic control in adults and children aged 10 and older with type 2 diabetes, and to reduce the risk of major adverse cardiovascular events — cardiovascular death, non-fatal heart attack or non-fatal stroke — in adults with type 2 diabetes and established cardiovascular disease. Victoza is not approved for weight loss [2].

FDA-approved generic liraglutide also exists, including generics that reference Saxenda for weight management and generics that reference Victoza for type 2 diabetes [6].

What doses are used?

Saxenda: 0.6 mg once daily for one week, then increases of 0.6 mg at weekly intervals to 1.2, 1.8 and 2.4 mg, reaching 3 mg daily from week 5. The recommended adult dose is 3 mg daily; the lower doses are for titration only, and the label says to discontinue if the 3 mg dose is not tolerated. The Saxenda label allows injection at any time of day, regardless of meals, in the abdomen, thigh or upper arm [1]. For adults, the label says to evaluate weight at 16 weeks and to stop if less than 4% of baseline body weight has been lost [1]. For children aged 12 and older, titration may take up to 8 weeks, and the dose may be reduced to 2.4 mg daily if 3 mg is not tolerated [1].

If a Saxenda dose is missed, the label says to resume the next scheduled daily dose without doubling up. If more than 3 days have passed since the last dose, the label says to restart at 0.6 mg and titrate again [1].

Victoza: adults start at 0.6 mg once daily for one week — the label notes this dose is not effective for glycemic control — then 1.2 mg daily, with an increase to a maximum of 1.8 mg daily after at least one week if more control is needed. Children aged 10 and older start at 0.6 mg and increase in 0.6 mg steps, to a maximum of 1.8 mg daily. The label says to inject Victoza and insulin separately and never to mix them [2].

How much weight does liraglutide produce?

The main weight trial behind the Saxenda label enrolled 3,731 adults without diabetes and a BMI of 30 or higher, or 27 or higher with treated or untreated dyslipidemia or hypertension. They received liraglutide 3 mg (2,487 people) or placebo (1,244) plus counseling on diet and exercise for 56 weeks [7]. The label reports a mean weight change of -7.4% with liraglutide versus -3.0% with placebo, a difference of 4.5 percentage points, with at least 5% weight loss in 62.3% versus 34.4% and more than 10% in 33.9% versus 15.4% [1]. The published report, analyzed a different way (last observation carried forward), gives 8.4 kg lost versus 2.8 kg [7].

In adults with type 2 diabetes, the SCALE Diabetes trial of 846 people reported label results at 3 mg of -5.4% versus -1.7% at 56 weeks, with at least 5% weight loss in 49% versus 16.4% [1][8].

In adolescents aged 12 to under 18, a 56-week trial of 251 participants found a BMI standard-deviation score difference of -0.22 (95% CI -0.37 to -0.08), with a BMI reduction of at least 5% in 43.3% versus 18.7% and at least 10% in 26.1% versus 8.1% [9].

Does liraglutide reduce cardiovascular risk?

Victoza carries its cardiovascular indication on the basis of LEADER, which randomized 9,340 adults with type 2 diabetes and high cardiovascular risk to liraglutide (1.8 mg target dose) or placebo on standard care for a median of 3.8 years. The primary composite of cardiovascular death, non-fatal heart attack or non-fatal stroke occurred in 13.0% versus 14.9% (hazard ratio 0.87, 95% CI 0.78 to 0.97), and cardiovascular death in 4.7% versus 6.0% (HR 0.78) [5][2].

Saxenda's approved uses do not include a cardiovascular indication; its label instead lists heart rate increase as a warning [1].

What side effects does liraglutide cause?

The Saxenda label pools five placebo-controlled adult trials: 3,384 people on Saxenda and 1,941 on placebo, for up to 56 weeks at 3 mg daily [1]. Rates with Saxenda versus placebo were nausea 39.3% vs 13.8%, diarrhea 20.9% vs 9.9%, constipation 19.4% vs 8.5%, vomiting 15.7% vs 3.9%, injection site reactions 13.9% vs 10.5%, headache 13.6% vs 12.6% and dyspepsia 9.6% vs 2.7% [1]. About 68% versus 39% reported any gastrointestinal disorder, nausea declined as treatment continued, and 9.8% versus 4.3% stopped treatment because of adverse reactions [1].

Victoza's type 2 diabetes trials involved different patients and doses, so their rates are not directly comparable with Saxenda's [2][1]. In pooled Victoza adult trials, nausea was 5% on placebo, 18% at 1.2 mg and 20% at 1.8 mg; diarrhea 4%, 10% and 12%; and vomiting 2%, 6% and 9% [2].

Hair loss is listed under postmarketing skin reactions in the Saxenda label with frequency not established; it does not appear in the trial tables [1].

What do the labels warn about?

Thyroid C-cell tumors (boxed warning). Liraglutide caused dose- and duration-dependent thyroid C-cell tumors in rats and mice at clinically relevant exposures, and whether it causes them in humans is unknown. Both Saxenda and Victoza are contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2 [1][2].

Acute pancreatitis. The labels say to discontinue if pancreatitis is suspected [1][2].

Gallbladder disease. In Saxenda adult trials, cholelithiasis was reported by 2.2% versus 0.8% on placebo and cholecystitis by 0.8% versus 0.4% [1].

Hypoglycemia with insulin or a sulfonylurea. In adults with type 2 diabetes taking a sulfonylurea, glucose below 54 mg/dL occurred in 28.2% on Saxenda versus 12.7% on placebo, with sulfonylurea doses cut by 50% at the start of that trial; the labels advise considering a lower dose of the insulin or sulfonylurea [1][2].

Heart rate. Mean resting heart rate rose 2 to 3 bpm in Saxenda-treated adults, and rises of more than 10 bpm at two visits occurred in 34% versus 19% on placebo; the label says to monitor heart rate [1].

Other label warnings include acute kidney injury from volume depletion, severe gastrointestinal reactions (the drug is not recommended in severe gastroparesis), serious hypersensitivity, and pulmonary aspiration during general anesthesia or deep sedation, with the label asking patients to tell the surgical team about planned procedures [1].

Pregnancy. The Saxenda label says to discontinue when pregnancy is recognized, and that weight loss offers no benefit in pregnancy [1].

The suicidal behavior and ideation warning was removed in 2026. On 2026-01-13 FDA asked the makers of Saxenda, Wegovy and Zepbound to remove the suicidal behavior and ideation language after reviewing a meta-analysis of 91 placebo-controlled GLP-1 trials (107,910 patients) and a claims cohort of 2,243,138 new users, finding no increased risk [10]. The Saxenda label effective 2026-02-25 no longer contains that warning [1].

Does liraglutide change birth control pills?

The Saxenda label says liraglutide delays gastric emptying but did not affect absorption of the oral drugs it was tested with to a clinically relevant degree. In an oral contraceptive study it lowered peak ethinyl estradiol by 12% and levonorgestrel by 13%, left ethinyl estradiol AUC unchanged, raised levonorgestrel AUC 18% and delayed Tmax by 1.5 hours. The label gives no instruction to switch or add contraception [1]. The tirzepatide label takes a different approach and advises a non-oral method or an added barrier method [11].

How does liraglutide compare with semaglutide?

Semaglutide injection is taken once weekly in Ozempic and Wegovy [12][13]. In STEP 1, 1,961 adults with obesity or overweight and no diabetes lost a mean 14.9% of body weight on semaglutide 2.4 mg weekly versus 2.4% on placebo at 68 weeks [3]; liraglutide's own weight trial showed 7.4% at 56 weeks [1]. Those figures came from trials with different populations, durations and analysis methods, so they do not show that one drug will work better for an individual.

Gastrointestinal side effects are the same class effect at different rates. In Wegovy 2.4 mg trials, nausea was 44% versus 16%, vomiting 24% versus 6%, diarrhea 30% versus 16% and constipation 24% versus 11% [13], against 39.3%, 15.7%, 20.9% and 19.4% for Saxenda [1]. Rates from different trials are not directly comparable [1].

The practical difference is the schedule: liraglutide is a daily injection, semaglutide a weekly one [1][13].

How does liraglutide compare with tirzepatide?

Tirzepatide is not a pure GLP-1 agonist. Its FDA label describes it as a GIP receptor and GLP-1 receptor agonist — a dual agonist [11]. In SURMOUNT-1, 2,539 adults with obesity or overweight and no diabetes lost 15.0%, 19.5% and 20.9% of body weight at 5, 10 and 15 mg at 72 weeks versus 3.1% on placebo [4]. Liraglutide 3 mg's label result was 7.4% at 56 weeks [1].

The head-to-head trials described here compared tirzepatide with semaglutide [14][15]. In SURMOUNT-5, 751 adults with obesity took tirzepatide at the maximum tolerated dose (10 or 15 mg) or semaglutide (1.7 or 2.4 mg) for 72 weeks, with weight change of -20.2% versus -13.7% [14]. In SURPASS-2, 1,879 adults with type 2 diabetes had HbA1c reductions of 2.01, 2.24 and 2.30 points on tirzepatide 5, 10 and 15 mg versus 1.86 points on semaglutide 1 mg at 40 weeks [15].