Liraglutide

What it is

Liraglutide is an acylated human GLP-1 receptor agonist with 97% amino-acid sequence homology to the body’s own GLP-1 [1]. It was the first of the long-acting GLP-1 injectables, with an initial US approval in 2010, and unlike the weekly agents it is injected once daily [1]. Novo Nordisk sells it as Victoza, for glycemic control in adults and children aged 10 and older with type 2 diabetes [1], and as Saxenda, for weight reduction and maintenance in adults and adolescents aged 12 and older with obesity, or adults with overweight plus a weight-related condition [2]. Both come as a 3 mL multi-dose pen containing 18 mg of liraglutide at 6 mg/mL [1]. Since Dec 23 2024 a generic liraglutide injection referencing Victoza has also been approved [3]. Doses are written in milligrams, which is how STACK logs them.

How it works

Native GLP-1 lasts only 1.5 to 2 minutes in the blood because two enzymes, DPP-4 and neutral endopeptidases, break it down [1]. Liraglutide is stable against both, and its pharmacokinetic profile comes from three things: self-association into clusters that delays absorption from the injection site, binding to plasma proteins, and that enzyme stability [1]. Like GLP-1 it binds and activates the GLP-1 receptor, increasing insulin secretion when glucose is high and decreasing glucagon secretion, both in a glucose-dependent way, and it delays gastric emptying [1]. Absolute bioavailability after subcutaneous injection is about 55%, and exposure is comparable from the upper arm, abdomen and thigh [1]. The Saxenda label adds that liraglutide delays gastric emptying, which is part of how it lowers food intake [2].

What the evidence shows

SCALE (NEJM 2015) enrolled 3,731 adults without diabetes with a BMI of at least 30, or 27 with dyslipidemia or hypertension. Participants received liraglutide 3.0 mg once daily or placebo for 56 weeks alongside lifestyle counselling; mean weight loss was 8.4 kg versus 2.8 kg, and 63.2% versus 27.1% lost at least 5% of body weight [4]. LEADER (NEJM 2016) followed 9,340 adults with type 2 diabetes and high cardiovascular risk for a median of 3.8 years; the composite of cardiovascular death, nonfatal heart attack or nonfatal stroke occurred in 13.0% on liraglutide versus 14.9% on placebo (hazard ratio 0.87), and cardiovascular death was 4.7% versus 6.0% [5]. Gastrointestinal events were the most common reason for stopping liraglutide in LEADER [5]. In SCALE, serious adverse events occurred in 6.2% on liraglutide versus 5.0% on placebo [4].

Regulatory status

Liraglutide is an FDA-approved drug. Victoza’s initial US approval was in 2010; its current label covers glycemic control in adults and pediatric patients aged 10 and older with type 2 diabetes, plus cardiovascular risk reduction [1]. Saxenda is approved for weight reduction and long-term maintenance in adults and pediatric patients aged 12 and older with obesity, and adults with overweight plus a comorbid condition [2]. On Dec 23 2024 FDA approved the first generic referencing Victoza (liraglutide injection 18 mg/3 mL), granted to Hikma Pharmaceuticals, noting that liraglutide was in shortage at the time and that the generic carries the same boxed warning [3]. On May 1 2026 FDA published a notice proposing not to include liraglutide on the 503B bulks list, tentatively finding no clinical need for outsourcing facilities to compound from bulk liraglutide; comments closed Jun 30 2026 [6]. This is the status as of Sep 24 2026.

Half-life and what it means for a level curve

The Victoza label states a plasma half-life of 13 hours after subcutaneous administration, and its pharmacokinetics section gives an elimination half-life of approximately 13 hours with an apparent clearance of about 1.2 L/h after a single subcutaneous dose [1]. The Saxenda label reports the same approximately 13 hours, with a clearance of 0.9 to 1.4 L/h [2]. The reference half-life in STACK is 13 hours. This is why liraglutide is a daily injection: with a 24-hour interval, only about 28% of a dose remains when the next one is given, so the curve shows a clear daily rise and fall around a plateau, and a missed day pulls the level down noticeably. With regular dosing a level reaches about 97% of steady state after about 5 half-lives, here roughly 65 hours, or under 3 days. STACK’s curve is an estimate from this published half-life, not a blood level.

Reported side effects

In Victoza’s placebo-controlled type 2 diabetes trials, the most common adverse reactions were nausea (18 to 20% versus 5% on placebo), diarrhea (10 to 12% versus 4%), headache, nasopharyngitis, vomiting (6 to 9% versus 2%), decreased appetite (9 to 10% versus 1%) and dyspepsia [1]. In Saxenda’s adult trials, nausea was reported by 39.3% (13.8% placebo), diarrhea by 20.9% (9.9%), constipation by 19.4% (8.5%) and vomiting by 15.7% (3.9%); in adolescents, nausea was 42.4% versus 14.3% and vomiting 34.4% versus 4.0% [2]. Both labels carry a boxed warning: liraglutide causes thyroid C-cell tumors in rodents, human relevance is unknown, and it is contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2 [1]. Other warnings include pancreatitis, hypoglycemia with insulin or sulfonylureas, renal impairment, hypersensitivity, acute gallbladder disease and pulmonary aspiration during anesthesia [1]. Tell your prescriber about anything unexpected.

Storage and handling

Before first use, store the Victoza or Saxenda pen in a refrigerator at 2°C to 8°C (36°F to 46°F), not in the freezer or directly against the cooling element; do not use a pen that has been frozen [1]. After first use, the pen can be kept for 30 days at room temperature (15°C to 30°C) or in the refrigerator, with the cap on and protected from excessive heat and sunlight, and should be thrown away 30 days after first use even if medicine remains [1]. Remove and discard the needle after each injection, and never share a pen, even with a new needle [1]. Both labels say to rotate injection sites within the same region to reduce the risk of cutaneous amyloidosis [2]. These pens are ready-to-use solutions with no mixing. If your prescriber gave you a product that requires reconstitution, STACK’s reconstitution calculator does the volume arithmetic; it does not suggest amounts.

What STACK tracks for it

STACK logs each liraglutide dose exactly as your prescriber wrote it, in milligrams, with the date and time. Because dosing is daily, the log is denser than for weekly agents, and the estimated level curve drawn from the 13-hour reference half-life makes a missed or late day easy to see. STACK stores the escalation schedule your prescriber gave you so you can see where you are on it, without proposing one. You can record the injection site each day across the abdomen, thigh and upper arm, which supports the label’s instruction to rotate within a region [1]. Weight, side effects and how long they lasted, and pen inventory are tracked alongside, including a 30-day countdown from the day each pen is first used [1]. STACK shows your data; it never prescribes.

The reference half-life in STACK

STACK's simulator and the app use 13 h for Liraglutide: approximately 13 hours; the Victoza and Saxenda labels state the same value. Measured in: adults after subcutaneous single doses (Victoza label, type 2 diabetes program; Saxenda label, obesity program).

Estimate only. Modelled from the published half-life you selected and the doses you logged — not a measured blood level. Do not use it to make medication decisions.

Free tools for Liraglutide

Read next

Sources

Every URL below was fetched and checked on 2026-09-24. Bracketed numbers in the text link here.

1. LabelVictoza (liraglutide) injection prescribing information, revised 11/2024
2. LabelSaxenda (liraglutide) injection prescribing information, revised 05/2025
3. FDAFDA Approves First Generic of Once-Daily GLP-1 Injection to Lower Blood Sugar in Patients with Type 2 Diabetes (Dec 23 2024)
4. TrialA Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management (SCALE), N Engl J Med 2015
5. TrialLiraglutide and Cardiovascular Outcomes in Type 2 Diabetes (LEADER), N Engl J Med 2016
6. FDAFederal Register, May 1 2026: List of Bulk Drug Substances for Which There Is a Clinical Need Under Section 503B