Retatrutide vs Mazdutide: Weight Loss, Side Effects and Status

Mazdutide is the nearer relative of retatrutide that already has an approval: China approved it for weight management in June 2025, and it hits two of retatrutide's three receptors, GLP-1 and glucagon, without GIP. In the mazdutide vs retatrutide comparison, retatrutide has the bigger published weight loss (25.0% on 12 mg at 80 weeks in TRIUMPH-1, counting everyone who started, against 16.65% for mazdutide 9 mg at 60 weeks in GLORY-2), but no trial has put them side by side.

The table below puts the two drugs next to each other. After it come the numbers behind each cell, and what those numbers can't tell you.

Do both hit glucagon, and what does GIP add?

Yes, both activate the glucagon receptor and the GLP-1 receptor. The GLORY-1 NEJM paper describes mazdutide as a dual GLP-1 and glucagon agonist, and Lilly's retatrutide adds a third target, GIP.

Nobody has published a trial built to isolate what the GIP receptor contributes, so the third receptor is an explanation, not a result. What the data do show is a gap in average loss that favors retatrutide. Our read: the gap is large enough to be real, but a good part of it may come from the people and trial lengths, because TRIUMPH-1 enrolled people who weighed about 19 kg more at the start and ran 20 weeks longer than GLORY-2.

How much weight do people lose on mazdutide?

In GLORY-1, 610 adults in China with obesity (or overweight plus a weight-related condition) got mazdutide 4 mg, 6 mg or placebo for 48 weeks. Counting everyone randomized (the paper's treatment-policy estimand), weight fell 11.00% on 4 mg and 14.01% on 6 mg, while placebo gained 0.30%. About half of the people on 6 mg (49.5%) lost at least 15%. Innovent's release gives -14.8% for 6 mg, a different method that assumes everyone stayed on treatment.

GLORY-2 tested 9 mg in 462 adults with a BMI of 30 or more, 16.1% of whom had type 2 diabetes. After 60 weeks, JAMA reports a 16.65% loss on mazdutide against 1.50% on placebo. Innovent's earlier release gave 18.55% against 3.02% for the same trial and 20.08% for the people without diabetes. The release doesn't label its method, so don't set it beside a treatment-regimen number from another trial.

How does mazdutide vs retatrutide weight loss compare?

TRIUMPH-1 randomized 2,339 adults without diabetes to retatrutide 4 mg, 9 mg, 12 mg or placebo for 80 weeks. NEJM's primary result, counting everyone randomized, was a 25.0% loss on 12 mg (23.7% on 9 mg) against 3.9% on placebo. Lilly's 28.3% figure is the efficacy estimand, which assumes everyone stayed on the drug. Set 28.3% beside Innovent's 14.8% for mazdutide 6 mg, and 25.0% beside the 14.01% from the paper.

Three things keep this from being a fair race.

1. Length: 80 weeks against 48 or 60. Innovent's GLORY-2 release says no plateau was seen at week 60, so mazdutide might have kept falling.
2. Starting point: TRIUMPH-1 averaged 112.7 kg, GLORY-2 94.0 kg and GLORY-1 87.2 kg. More weight to lose means bigger kilogram changes, and China's label sets obesity at a BMI of 28, below the usual US cutoff of 30.
3. Doses: mazdutide's top tested dose is 9 mg. Retatrutide's 12 mg is a different drug at a different potency, so milligrams don't line up.

For retatrutide's full set of trials, see retatrutide weight loss results.

Side effects and dropouts

Both drugs mostly cause stomach side effects. The percentages below come from each trial's top dose.

The odd part is that vomiting was more than twice as common on mazdutide 9 mg, yet far fewer people left the trial. Possible reasons are the trial setting, the dose steps (GLORY-2's release mentions only a 2-step titration) and how adverse events were recorded, and we can't say which. Retatrutide also has a side effect with no mazdutide counterpart in these papers: burning or oversensitive skin (dysesthesia), in 12.5% on 12 mg against 0.9% on placebo in TRIUMPH-1. Our retatrutide side effects guide covers it.

Where is mazdutide approved, and what about the US?

China's NMPA approved mazdutide for chronic weight management in adults with a BMI of 28 or more, or 24 or more with a weight-related condition. Innovent announced it on June 27, 2025, and said it was the first dual GLP-1 and glucagon drug approved for weight loss. A type 2 diabetes approval followed, announced September 19, 2025. Innovent holds the China rights under a license from Lilly.

The 9 mg dose is a separate matter. Innovent said on November 25, 2025 that China's regulator had accepted a supplementary application for 9 mg, and we found no approval of it as of October 31, 2026. The approved range tops out at 6 mg, the higher dose in GLORY-1; Innovent's November release describes the broad-population regimen as 2 mg-4 mg-6 mg.

In the US, mazdutide has no approval, and we found no Lilly-sponsored Phase 3 trial. ClinicalTrials.gov lists Lilly Phase 2 studies, including weight management in 179 adults with obesity or overweight (completed January 2025), and alcohol use disorder in 308 people (completed March 2026), alongside Phase 1 work. Innovent's GLORY-3 trial against semaglutide 2.4 mg in 479 Chinese adults has an estimated primary completion of December 2026, and it is the closest thing to a head-to-head with an approved drug that we found for the obesity indication. The FDA has also warned companies selling unapproved mazdutide online.

Retatrutide is further along in the US than mazdutide, but not approved. Lilly last said, on September 29, 2026, that it plans to submit retatrutide to the FDA in the first quarter of 2027 as a Biologics License Application (BLA). On October 2, 2026, the FDA decided that retatrutide is a drug, not a biological product, so an application would need to be filed under section 505 of the Federal Food, Drug, and Cosmetic Act. Lilly's appeal on that question is pending in the Seventh Circuit, and we found no ruling as of October 31, 2026. Our retatrutide release date page tracks the timeline.

Dosing

Both are once-weekly injections. The mazdutide doses tested were 4 mg, 6 mg and 9 mg. We couldn't find the approved starting dose or titration schedule in the English releases and papers we read, so we aren't giving one. Retatrutide's trials started at 2 mg and stepped up every 4 weeks, reaching 12 mg through 2, 4, 6 and 9 mg. Dosing belongs to a prescriber working from the label or protocol.

Anything sold online as either drug isn't Lilly's or Innovent's product. If you're tempted by a retatrutide for sale listing, a vial's label can't tell you what's inside.

Questions to take to a doctor

Mazdutide only matters to you if you live in China or are in a trial, since it isn't sold legally elsewhere. For anyone else, the useful questions are about what's approved now. Ask whether tirzepatide or semaglutide fits your health history, and read retatrutide vs tirzepatide for the nearest approved comparison. Survodutide is the other GLP-1 and glucagon drug in late trials, covered in retatrutide vs survodutide. The wider pipeline sits in new weight loss drugs.

Get medical help right away for severe stomach pain that won't ease, vomiting that stops you keeping fluids down, or signs of an allergic reaction, on any of these drugs.