Tirzepatide vs Liraglutide
It is the weekly shot behind Mounjaro and Zepbound, used for diabetes and weight loss. Large trials show 15% to 21% weight loss. It is a daily injection for type 2 diabetes and for weight loss. Large trials of 9,340 and 3,731 people showed fewer heart problems and about 8% weight loss.
Both sit at grade A: strong human evidence. Both are FDA approved.
Evidence
AStrong human evidence
AStrong human evidence
Human studies cited
Animal or cell studies cited
Why the grade
Tirzepatide's weight-loss use rests on the SURMOUNT program of randomized placebo-controlled trials, the largest being SURMOUNT-1 with 2,539 adults, plus trials in type 2 diabetes, sleep apnea, weight maintenance and diabetes prevention. Every approved indication was granted on randomized data, so it grades A.
Both uses rest on large randomized placebo-controlled trials: LEADER (9,340 patients with type 2 diabetes, cardiovascular outcomes) and the SCALE obesity trial (3,731 adults, 56 weeks of weight loss). Multiple other phase 3 trials sit behind the labels. What the citations do not cover is how liraglutide compares with the newer weekly GLP-1 drugs, which outperform it on weight.
FDA
FDA approved
Tirzepatide is approved by the FDA as Mounjaro (2022) for type 2 diabetes in adults, extended to children 10 and older and to cardiovascular risk reduction in adults with type 2 diabetes and established cardiovascular disease, and as Zepbound (2023) for chronic weight management and for moderate to severe obstructive sleep apnea in adults with obesity.
FDA approved
Approved. Liraglutide is sold as Victoza (approved 2010) for type 2 diabetes in adults and children aged 10 and older and to reduce major cardiovascular events in adults with type 2 diabetes and heart disease, and as Saxenda (approved 2014) for chronic weight management in adults and adolescents aged 12 and older. Generic liraglutide for both indications has been approved since December 2024 and August 2025.
Sold for
Tirzepatide is the weight-loss injection that outperformed semaglutide, cutting body weight by about a fifth in trials.
Liraglutide was the first daily GLP-1 drug to be approved for weight loss and is now marketed as the cheaper generic alternative to semaglutide for people who want a GLP-1 but cannot get or afford the newer ones.
Studies say
Multiple large randomized trials show weight loss of 15 to 21 percent, better glucose control than other diabetes drugs, and improvement in sleep apnea, with weight regain after stopping, which is a clean A.
Trials in nearly 10,000 diabetic patients and 3,700 adults with obesity showed fewer heart events and about 8 percent body weight loss respectively, which earns an A for both approved uses.
Class
Dual GIP + GLP-1 receptor agonist
GLP-1 receptor agonist
Route
Injection
Injection