Liraglutide

First-generation GLP-1 receptor agonist (Saxenda / Victoza) - daily-injected with ~13 h half-life. The original of the modern GLP-1 family, now eclipsed in potency by semaglutide and tirzepatide but with real clinical history and finer day-by-day side-effect control.

FDA-approvedNot currently WADA-prohibitedInjectableGLP-1

Key facts

Common routesSC

Half-life13 hours

Typical range0.6–3.0 mg/day

Résumé

Liraglutide is a first-generation GLP-1 receptor agonist with 97% homology to human GLP-1, modified with a palmitic-acid side chain that binds albumin - extending the half-life from minutes (native GLP-1) to about 13 hours. It was the first GLP-1 to reach broad clinical use: approved as Victoza for T2D in 2010 and Saxenda for obesity in 2014.

Today liraglutide is less potent than semaglutide and tirzepatide and requires daily injections. But it retains niches: finer day-by-day side-effect control (you can skip a dose when nauseous), lower per-unit cost in some markets, and a longer real-world safety track record than the weekly compounds.

Notes sur le mécanisme

GLP-1 receptor agonism

Activates GLP-1 receptors in pancreas and brain - the foundational incretin signal. Glucose-dependent insulin secretion, glucagon suppression, central satiety signals.

Slowed gastric emptying

Slows the movement of food from stomach into small intestine. Physically makes you feel full sooner and longer - the mechanism that drives nausea when titration moves too fast.

Hypothalamic appetite suppression

Acts on the arcuate nucleus of the hypothalamus to reduce hunger signals and cravings. The "food noise gets quieter" phenomenon users report.

Dosing patterns

Saxenda obesity protocol

Daily SC injection, titrated weekly by 0.6 mg: 0.6 → 1.2 → 1.8 → 2.4 → 3.0 mg/day. Maintenance dose 3.0 mg daily. Holding a step longer is fine if tolerability isn't there.

Cutting / biohacker protocol

Lower maintenance doses (1.2–1.8 mg daily) for 4–8 weeks, often as an adjunct to diet and training. The advantage over semaglutide here: daily control allows fast discontinuation or reduction on side effects.

Dosing timing

Peak serum levels ~11 h after injection. Some users inject in the evening to sleep through the nausea peak; others morning to maximise daytime satiety. Either pattern works - pick one and stay consistent.

Aperçu des données

Tier: Clinical. Over a decade of FDA-approved use, extensive Phase III trial data, multiple cardiovascular outcome trials. Fully characterised efficacy and safety profile.

Phase III data

SCALE Obesity (Pi-Sunyer 2015): ~8% mean weight loss at 3.0 mg over 56 weeks vs ~2.6% placebo. LEADER (T2D): cardiovascular risk reduction in diabetic population.

Real-world data

Over a decade of clinical use. Safety and tolerability profile is known from large patient cohorts; not dependent on trial-selection bias.

Considérations de sécurité

One of the best-characterised safety profiles in the peptide space. Main concerns are GI (nausea, vomiting) on fast titration; rare but serious issues include pancreatitis and the black-box warning for thyroid C-cell tumours (rat data; human risk unclear). Pre-protocol thyroid history check is not optional.

Common cautions

Nausea / vomiting - the most common side effect; worst in the first 4 weeks
Contraindicated in personal or family history of medullary thyroid carcinoma (MTC) or MEN2 syndrome
Contraindicated in acute pancreatitis history; check lipase if epigastric pain emerges during use
Gallstone risk modestly elevated - rapid weight loss is the driving factor