Semaglutide vs Mazdutide
It is the shot behind Ozempic and Wegovy, used for diabetes and weight loss. Trials in tens of thousands of people show about 15% weight loss and fewer heart attacks. It is a weekly weight-loss shot approved in China. Two trials in over 1,000 adults there showed about 15% weight loss, but no US trial has finished.
Both sit at grade A: strong human evidence. Semaglutide: FDA approved. Mazdutide: In clinical trials.
Evidence
AStrong human evidence
AStrong human evidence
Human studies cited
Animal or cell studies cited
Why the grade
Semaglutide has one of the largest trial programs of any peptide: the STEP trials in obesity (STEP 1, 1,961 adults), the SUSTAIN trials in type 2 diabetes, SELECT (17,604 adults with cardiovascular disease and obesity, the largest), FLOW in kidney disease, and systematic reviews pooling tens of thousands of participants. Weight loss, glucose lowering and reductions in heart attack, stroke and kidney outcomes are all shown in randomized placebo-controlled trials. What remains open is what happens over decades and how to stop without regaining.
Mazdutide has completed multiple phase 3 randomized placebo-controlled trials in China: GLORY-1 in 610 adults with overweight or obesity and GLORY-2 in 461 adults with obesity, plus the DREAMS trials in type 2 diabetes, and it won two approvals on that basis. That meets the A definition. The limits are that nearly all trial participants were Chinese, no cardiovascular outcomes trial has reported, and US data are limited to one phase 2 trial of 179 people.
FDA
FDA approved
Semaglutide is FDA-approved as Ozempic (weekly injection, type 2 diabetes, 2017; with later indications to reduce cardiovascular events and, since January 2025, kidney disease progression in type 2 diabetes), Rybelsus (daily tablet, type 2 diabetes, 2019), and Wegovy (weekly injection, chronic weight management, 2021; cardiovascular risk reduction in obesity, 2024; MASH with liver fibrosis, 2025; an oral Wegovy tablet, December 2025). Compounded semaglutide is not FDA-approved.
In clinical trials
Not approved by the FDA for any use. Mazdutide is approved in China, where the NMPA cleared it in June 2025 for chronic weight management in adults with overweight or obesity and in September 2025 for glycemic control in type 2 diabetes. In the US it is investigational, with Eli Lilly holding the rights, one US phase 2 trial published and no phase 3 result or FDA filing reported.
Sold for
Semaglutide is the GLP-1 injection behind Ozempic and Wegovy, the most talked-about weight loss drug of the decade.
Mazdutide is pitched as the next step after tirzepatide: a weekly dual agonist that adds glucagon receptor activity to GLP-1 for more weight loss and liver fat reduction, and it is already being sold by gray-market peptide vendors in the US.
Studies say
Randomized trials in tens of thousands of people show about 15 percent weight loss, roughly a 1 to 2 point HbA1c reduction, a 20 percent cut in major cardiovascular events and slower kidney decline, with gastrointestinal side effects and weight regain after stopping as the main caveats.
Two phase 3 trials in more than a thousand Chinese adults produced about 15 percent weight loss versus placebo over 48 to 60 weeks and led to approval in China, which grades A, although no US trial has finished and no outcomes trial exists.
Class
GLP-1 receptor agonist
GLP-1 / glucagon dual agonist
Route
Several routes
Injection