Liraglutide

What is liraglutide?

Liraglutide is an FDA-approved GLP-1 receptor agonist and the drug that opened this whole category. It predates semaglutide and tirzepatide, and it is still prescribed today: as Victoza for type 2 diabetes and as Saxenda for weight management. The defining difference from the newer drugs is the schedule. Liraglutide is a daily injection, not a weekly one.

How liraglutide works

Liraglutide is a close analog of human GLP-1, sharing about 97% of its structure. A fatty-acid chain lets it bind reversibly to albumin in the blood, which slows its clearance and stretches its half-life to roughly 13 hours, enough for once-daily dosing but not once-weekly. Like the rest of the class, it curbs appetite and food intake through GLP-1 signaling in the brain, slows gastric emptying, and improves glucose-dependent insulin release. Its weight effect comes from eating less, not from burning more.

What the research shows

In the SCALE Obesity and Prediabetes trial, adults on the 3.0 mg dose lost about 8% of their body weight over 56 weeks, versus roughly 2.6% on placebo. That is real, randomized, human-trial evidence, and it is what earned Saxenda its 2014 approval. It is also visibly less than what weekly semaglutide (about 15%) and tirzepatide (about 21%) later achieved, which is the main reason liraglutide has been overshadowed despite working.

Dosage and how it is used

For weight management, liraglutide starts at 0.6 mg once daily and steps up by 0.6 mg each week to a 3.0 mg maintenance dose, a five-week ramp designed to limit nausea. The diabetes product (Victoza) tops out lower. The daily injection is the practical trade-off: more injections than the weekly drugs, which some people find harder to stay consistent with.

→ How to reconstitute liraglutide: calculator, units to draw & storage

Side effects and safety

The side effects are the familiar GLP-1 pattern and peak during the weekly titration. In SCALE, nausea affected roughly 39% of people on active treatment and vomiting about 15%, alongside diarrhea, constipation, and reduced appetite. Liraglutide carries the same thyroid C-cell tumor boxed warning as the rest of the class and the same contraindication for a personal or family history of medullary thyroid carcinoma or MEN 2. Its long clinical track record is a point in its favor.

• Research depth: extensive. Human clinical trials: yes, with a long track record.
• Daily injection, unlike the weekly newer drugs. GI side effects are common but usually transient.
• Prescription medicine in the US. Verify current legal and regulatory status independently.

Frequently asked questions

References

• Pi-Sunyer X et al. A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management (SCALE). New England Journal of Medicine, 2015.
• Saxenda (liraglutide 3 mg) prescribing information and mechanism overview. Novo Nordisk.