Liraglutide

Liraglutide is human GLP-1(7-37) with a Lys34Arg substitution and a C16 palmitic acid attached via a glutamic acid spacer at Lys26. The fatty acid drives albumin binding and self-association at the injection site, extending the half-life from minutes to about 13 hours - enough for daily dosing but not weekly. Receptor pharmacology is otherwise identical to semaglutide; the difference is exposure, which is why the weight-loss ceiling is roughly half. LEADER established cardiovascular benefit in type 2 diabetes.

Targets: GLP-1 receptor

• · 600 mcg daily for one week, then increase by 600 mcg weekly to 3000 mcg. If you cannot tolerate 3000 mcg after two weeks at 2400, the drug is usually abandoned.
• · 600 mcg for a week, then 1200 mcg, then 1800 mcg if needed.

Work out your exact syringe units →

• very commonNausea— More persistent day to day than with weekly agents because of the daily peak.
• commonVomiting and diarrhoea
• commonInjection-site reactions— More frequent than weekly drugs simply because of injection count.
• uncommonGallstones
• rarePancreatitis

• Personal or family history of medullary thyroid carcinoma or MEN2 - boxed warning.
• History of pancreatitis.
• Pregnancy.

• cautioninsulin-analogues — Hypoglycaemia risk; the fixed combination Xultophy exists precisely because the pairing needs careful ratios.
• cautionsulfonylureas (glimepiride, gliclazide, glipizide) — Real hypoglycaemia risk - unlike liraglutide alone, sulfonylureas drive insulin release independently of glucose. Labels advise reducing the sulfonylurea dose when a GLP-1 agonist is started.
• redundantsemaglutide — Same receptor, weaker version.

• · Weight and waist.
• · HbA1c where relevant.
• · Heart rate.
• · Gallbladder symptoms during rapid loss.

FDA- and EMA-approved as Victoza and Saxenda; generic liraglutide is now available in several markets.

• Pi-Sunyer et al. 2015, SCALE Obesity and Prediabetes, NEJM (trial)
• Marso et al. 2016, LEADER, NEJM (trial)
• Saxenda and Victoza US prescribing information (label)

Pharmacologically liraglutide is the same drug as semaglutide at the receptor; everything that differs is exposure engineering. The C16 palmitoyl chain produces two protraction effects: heptamer self-association at the subcutaneous depot, which slows absorption to an 11-hour tmax, and albumin binding in plasma, which slows clearance. Neither is as effective as semaglutide's C18 di-acid plus AEEA spacers, and there is no Aib at position 8, so DPP-4 still degrades it. The result is a daily peak-and-trough profile rather than a flat one, and that shapes the clinical experience in ways people underestimate. Nausea recurs daily around tmax instead of clustering after a weekly injection. Gastric emptying delay is less subject to the tachyphylaxis that long-acting agents show, so postprandial glucose control per unit of weight loss is relatively better. And because trough concentrations dip, central appetite suppression is less continuous, which is part of why the weight-loss ceiling is roughly half of semaglutide's. The three-day steady state also means titration steps can be weekly rather than four-weekly, which is the one practical advantage: you find your tolerable dose in five weeks rather than five months. LEADER established that GLP-1 receptor agonism reduces cardiovascular events in type 2 diabetes, and it did so before semaglutide - historically this is the trial that made the class cardiovascular therapy rather than only glucose therapy.

The daily injection is the drug's real weakness and the main reason people stop. Seven injection sites a week means more injection-site reactions and more chances to skip. The second problem is that nausea does not habituate away as cleanly as it does with weekly agents, because a fresh peak arrives every day around hour 11. Third, people transfer semaglutide's four-week titration habit onto liraglutide and stay at 1.2 mg for months, getting the side effects without the effect - the correct schedule is weekly steps. Fourth, expecting semaglutide results. Eight percent is the honest ceiling, and someone who was promised fifteen will be disappointed and quit.

1. 600 mcgWeek 1 — Saxenda schedule. Weekly steps are possible because steady state is reached in about three days.
2. 1.2 mgWeek 2
3. 1.8 mgWeek 3 — This is the Victoza maximum for type 2 diabetes.
4. 2.4 mgWeek 4
5. 3 mgWeek 5 onward — The SCALE obesity dose. If you cannot reach it after two weeks at 2400 mcg, the drug is usually abandoned rather than held - the effect at lower doses is not worth seven injections a week.

• GLP-1 receptor (GLP1R) — High-affinity full agonist; the commonly quoted receptor affinity is close to that of native GLP-1, and albumin binding rather than affinity is what limits free drug

  Glucose-dependent insulin secretion, glucagon suppression, delayed gastric emptying, central satiety, modest heart-rate increase.

• Albumin — Greater than 98% bound

  Reversible C16 palmitate binding providing the depot effect. Weaker than semaglutide's di-acid, hence the 13-hour half-life.

• SCALE Obesity and Prediabetes Phase 3 · n=3731 · 56 weeks · 2015

  Mean weight loss of 8.0% with liraglutide 3.0 mg versus 2.6% with placebo.

• LEADER Phase 3 cardiovascular outcomes · n=9340 · 182 weeks · 2016

  13% relative reduction in major adverse cardiovascular events in type 2 diabetes - the first positive GLP-1 cardiovascular outcomes trial.

Days 1-3: steady state is essentially reached, which is unusually fast for this class. Week 1-5: weekly escalation, with nausea recurring around each daily peak. Weeks 4-12: appetite suppression stabilises. Months 6-8: weight plateaus, at roughly 8% mean loss. Stopping: because the half-life is 13 hours, appetite returns within about two days rather than two weeks - the rebound is more abrupt than with weekly drugs.

Liraglutide's practical niche now is cost. Generics have arrived in several markets and it is often the cheapest legitimate GLP-1 available, which makes it a reasonable entry point for someone who wants a licensed product rather than a grey-market vial. There is a licensed fixed combination with insulin degludec (Xultophy) that exists precisely because the insulin-plus-GLP-1 pairing needs careful ratios. Do not run it alongside semaglutide, dulaglutide or any other GLP-1 agonist - same receptor, no additive benefit, additive nausea. The daily dosing makes it a slightly better partner for a short-acting amylin analogue like pramlintide than the weekly agents are, though nobody has studied that combination properly.

Against semaglutide: same receptor, roughly half the weight loss, seven times the injections. The only reasons to choose liraglutide are cost and the faster titration to a known tolerable dose. Against dulaglutide: liraglutide is the better weight drug, dulaglutide the more convenient diabetes drug. Against exenatide immediate-release: liraglutide wins on everything except postprandial glucose control specifically. Historically it matters more than it does clinically now - LEADER is the trial that established the whole class as cardioprotective.

$90–$1400/month. Generic liraglutide has changed this substantially in some markets and can be under 150 per month; brand Saxenda without coverage remains around 1,300-1,400. Market observation from mid-2026, not verified pricing.

• ?The volume of distribution figure (20-25 L) is for the 3.0 mg obesity dose; lower diabetes doses give different values and the label reports them separately.
• ?The sequence given is the standard published one and matches the label's description of the Lys26 acylation and Lys34Arg substitution, but was not verified residue-by-residue against a primary structural source.
• ?Receptor affinity relative to native GLP-1 was not independently resolved in this session.
• ?How much of the efficacy gap versus semaglutide is exposure versus receptor kinetics has not been separated experimentally.
• ?Cost figures are market observations, not verified pricing.

• A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management Pi-Sunyer X et al., N Engl J Med, 2015 · PMID 26132939

  SCALE. The reference point for what a first-generation daily GLP-1 does.

• Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes Marso SP et al., N Engl J Med, 2016 · PMID 27295427

  LEADER - the trial that turned GLP-1 agonists into cardiovascular drugs.

• SAXENDA (liraglutide) injection - US prescribing information, section 12.3 Novo Nordisk, DailyMed

  Source for 55% bioavailability, 20-25 L volume of distribution, 0.9-1.4 L/h clearance, greater than 98% protein binding, 11-hour tmax and the 6%/5% urine and faecal metabolite recovery.

• Efficacy and safety of semaglutide compared with liraglutide and placebo for weight loss in patients with obesity O'Neil PM et al., Lancet, 2018 · PMID 30122305

  Direct comparison against semaglutide with liraglutide 3.0 mg as the active comparator.