Mazdutide: What the Trials Show, and Why It Is Approved Only in China

Mazdutide is a weekly injection that activates both the GLP-1 and glucagon receptors, and it is approved only in China, where regulators cleared it for weight management in June 2025 and for type 2 diabetes in September 2025.^[12][13] In the phase 3 trial behind the obesity approval, Chinese adults on the 6 mg dose lost 14.0% of their weight at 48 weeks, against a small gain on placebo.^[1] A 9 mg dose reached 16.7% at 60 weeks.^[2] Nausea, vomiting and diarrhea were common and rose with dose. In the United States mazdutide is not approved. Lilly has run only mid-stage trials there, and neither company has announced a US filing.^[5][20]

What mazdutide is

Mazdutide carries two code names: LY3305677 at Eli Lilly and IBI362 at Innovent Biologics, which develops it in China under an exclusive license from Lilly.^[12][10] In China it is sold under the brand name Xinermei.^[10] Lilly has kept running its own trials in the United States, so the molecule now has two development programs moving at very different speeds.^[5][20]

Semaglutide works through one hormone receptor, GLP-1. Tirzepatide adds GIP. Mazdutide pairs GLP-1 with glucagon, a hormone that acts mostly on the liver. Innovent’s case for adding glucagon is that it curbs fat production in the liver and speeds fat breakdown there.^[12] Two other drugs use the same pairing: Boehringer Ingelheim’s survodutide, which has finished phase 3 obesity trials but has no approval, and Altimmune’s pemvidutide, now aimed at liver disease. Lilly’s retatrutide adds GIP on top of GLP-1 and glucagon. As of October 2026, mazdutide is the only one of the four with an approval anywhere.

How much weight people lost

Five randomized obesity trials of phase 2 or later have reported in journals. Four ran in China; one ran in the United States. They used different doses and lasted from 24 to 60 weeks, so the rows below describe separate experiments, not a ranking.

GLORY-1 is the trial China’s approval mainly rests on.^[12] Its main analysis counted every participant whatever happened to their treatment. At the 32-week primary endpoint, 82.0% of people on 6 mg had lost at least 5% of their weight, against 10.5% on placebo. By week 48, 49.5% on 6 mg had lost at least 15%.^[1] In GLORY-2, the 9 mg trial, 84.3% reached the 5% mark, against 33.1% on placebo.^[2]

The American trial, paid for by Lilly, went to doses China has not tested in phase 3. Its posted results show weight loss still growing at week 48: 10.5% in the 3-to-6 mg arm, 19.2% on 10 mg and 22.3% on 16 mg, with placebo flat.^[18] Read these with two cautions. The headline figures assume participants kept taking their assigned dose, the so-called efficacy estimand.^[5] And each dose arm held only 32 to 51 people.^[18]

Why press releases show bigger numbers

Innovent’s releases often quote the efficacy estimand, which leaves out what happened after people stopped treatment. For GLORY-1 it reported 14.8% at 48 weeks on 6 mg, against 14.0% in the journal’s all-participants analysis.^[12][1] For GLORY-2 it reported 18.55%, and 20.08% in the participants without diabetes, against 16.65% in JAMA.^[14][2] Both sets of numbers are correct for the question each one asks. The journal figure is closer to what happens to everyone who starts.

Type 2 diabetes results

China’s diabetes approval rests on two phase 3 trials, DREAMS-1 and DREAMS-2, published back to back in Nature.^[13] HbA1c is a measure of average blood sugar over about three months.

Dulaglutide, sold as Trulicity, is an older GLP-1 drug, so DREAMS-2 compared mazdutide against an active treatment rather than a dummy. Mazdutide beat it on both blood sugar and weight, and caused more gut side effects.^[7] Both trials ran 24 to 28 weeks, about half the length of the obesity trials, which is one reason their weight figures sit lower.

Against semaglutide: DREAMS-3

DREAMS-3 put mazdutide 6 mg against semaglutide 1 mg, an Ozempic dose, in 349 people in China who had both obesity and type 2 diabetes. It was open-label, meaning participants knew which drug they got, and its main goal was the share reaching both an HbA1c under 7% and at least 10% weight loss by week 32.^[9] Innovent says 48.0% on mazdutide got there, against 21.0% on semaglutide, with average weight loss of 10.29% versus 6.00%.^[16] Those results are company-reported. Only the trial’s design has appeared in a journal. Semaglutide 1 mg is also below the 2.4 mg Wegovy dose used for weight loss, so DREAMS-3 says nothing about mazdutide against Wegovy. GLORY-3, a second head-to-head trial against semaglutide in people with fatty liver disease, is still under way; its registry entry estimates primary completion at the end of 2026.^[21]

Side effects by dose

The complaints are the familiar GLP-1 ones, led by nausea, vomiting, diarrhea and constipation, and most were rated mild or moderate. What changes with mazdutide is how steeply they climb at the higher doses.

At the 4 mg and 6 mg doses China approved, very few people quit GLORY-1 because of side effects.^[1] At 9 mg, about half of GLORY-2 participants vomited, yet only 2.9% stopped.^[2] The 16 mg dose in the American trial is where tolerability broke: two in three had nausea, nearly half vomited, and one in five stopped treatment because of adverse events.^[18][5] Serious adverse events were rare in every arm of that trial, and no one died.^[18] In the phase 2 diabetes trial, low blood sugar occurred in 10% on mazdutide and 8% on placebo.^[8]

Heart rate

Glucagon in high doses quickens the heartbeat, so cardiologists watch this class closely.^[11] A 2026 review in the Journal of the American Heart Association found that mazdutide and survodutide raised heart rate about as much as GLP-1 drugs do on their own, and that both lowered blood pressure.^[11] No heart-outcomes trial of mazdutide has reported. Our page on GLP-1 drugs and heart rate explains the class effect.

Where mazdutide is approved

• China, weight management (June 27, 2025). Approved for adults with a BMI of 28 or more, or 24 or more with at least one weight-related condition, alongside diet and exercise.^[12][10]
• China, type 2 diabetes (September 19, 2025). Approved for blood sugar control in adults, based on DREAMS-1 and DREAMS-2.^[13]
• China, 9 mg dose (pending). Regulators accepted Innovent’s 9 mg application in November 2025.^[15] Innovent’s August 2026 results presentation still listed 9 mg approval as a milestone ahead, with only the 4 mg and 6 mg doses shown as approved.^[17]
• United States: not approved. No US marketing application has been announced.

Is mazdutide coming to the US?

Not on any timetable either company has published. Innovent’s license covers China.^[12] The American trials are Lilly’s, and they are mid-stage. ClinicalTrials.gov lists a completed US phase 2 obesity trial (the one in the table above),^[18] a completed phase 2 study in alcohol use disorder with no results posted,^[19] and a recruiting Lilly master protocol for weight management that includes LY3305677 among several experimental drugs.^[20] Every phase 3 mazdutide trial on the registry is in China. A US approval would normally rest on phase 3 trials, and none has been registered here.

The American trial tested doses up to 16 mg, well above anything approved in China.^[5] In China, Innovent’s pipeline lists programs in sleep apnea, fatty liver disease and adolescents, plus a comparison of mazdutide 15 mg against tirzepatide 15 mg.^[17] Our GLP-1 pipeline tracker follows each readout as it lands.

What is still unknown

• How it performs outside China. Every phase 3 result comes from Chinese adults. The only data from elsewhere are a 179-person phase 2 trial in the United States.^[5]
• Long-term outcomes. The longest trial ran 60 weeks.^[2] No trial has measured heart attacks, strokes or deaths.
• Liver benefit. Innovent reports a 71.9% average drop in liver fat on 9 mg in a GLORY-2 subgroup with high liver fat at baseline.^[14] That figure is company-reported and covers part of the trial only; liver-specific trials are still running.^[21]
• Against Wegovy or Zepbound. No trial has yet reported a comparison of mazdutide with semaglutide 2.4 mg for weight loss or with tirzepatide at any dose. Until such trials report, rankings of the newer agents rest on comparisons across separate trials.

Mazdutide sold online in the US

Mazdutide is not legal to sell to consumers in the United States, yet it turns up on peptide websites labeled for research. FDA’s page on unapproved GLP-1 drugs names it, alongside semaglutide, tirzepatide, retatrutide and survodutide, as a drug the agency has warned companies about for selling it with false research-only or not-for-people labels.^[22] Our warning-letter tracker holds four letters to sellers whose catalogs listed mazdutide by name. The earliest two went out on the same day in December 2024, to Xcel Research and Summit Research Peptides; the latest went to NuScience Peptides in August 2026. In each, FDA classed the products as unapproved new drugs.^{[24][25][26][27]}

Nor can a US pharmacy legally compound it. Under federal rules, a compounding pharmacy may use an ingredient only if it meets a USP or NF standard, already sits inside an FDA-approved product, or is on FDA’s 503A bulks list.^[23] No FDA-approved drug contains mazdutide, and it is not on that list. A vial shipped from China under the Xinermei name is not FDA-approved either. Our explainer on what cannot legally be compounded sets out the rules in full.