Mazdutide

Mazdutide is a synthetic mammalian oxyntomodulin (OXM) analog that activates both the glucagon receptor (GCGR) and the GLP-1 receptor. It has been structurally modified with a fatty-acyl moiety to extend its half-life sufficient for once-weekly subcutaneous dosing. The compound has research designations IBI362 (Innovent) and LY3305677 (Lilly). It was first regulatory-approved by China's National Medical Products Administration (NMPA) on June 27, 2025 for chronic weight management. A second NMPA approval in September 2025 added the type 2 diabetes indication. It is marketed in China as Xinermei by Innovent Biologics.

The molecule's biological origin is oxyntomodulin, a 37-amino-acid peptide naturally produced by L-cells in the intestine. OXM activates both GCGR and GLP-1R as part of normal postprandial signaling. Native OXM has a very short half-life and is not viable as a therapeutic. Mazdutide preserves the dual receptor activity of OXM while adding structural modifications (particularly the fatty-acyl moiety, similar to the engineering used in semaglutide and liraglutide) that enable once-weekly dosing.

Innovent acquired exclusive Chinese rights from Eli Lilly in 2019. Lilly retains rights outside China. The Chinese Phase 3 program (GLORY-1 in obesity, DREAMS-2 in type 2 diabetes) supported the NMPA approval. Phase 2 development is underway in the United States. No FDA approval has been submitted at the time of writing.

The Chinese approval is for adults with BMI ≥28 kg/m² or BMI ≥24 kg/m² with weight-related comorbidities. The threshold is lower than typical Western obesity criteria, reflecting Chinese clinical guidelines and the substantial prevalence of overweight (more than 500 million Chinese adults) at lower BMI levels.

The Chinese Phase 3 Evidence

The mazdutide approval was based on the GLORY-1 and DREAMS-2 Phase 3 trials in Chinese patients.

GLORY-1 in obesity. Randomized Chinese obesity patients to mazdutide doses or placebo over 48 weeks. The trial reported clinically meaningful weight loss compared with placebo, with additional improvements in waist circumference, lipid profile, blood pressure, and liver enzymes. The detailed efficacy magnitudes have been incompletely published in English-language literature but supported regulatory approval.

DREAMS-2 in type 2 diabetes. Chinese T2D patients with inadequate glycemic control on metformin. Mazdutide reduced HbA1c and produced significant weight loss compared with placebo. The September 2025 NMPA approval expanded the indication to include T2D in adults.

Mazdutide vs comparator GLP-1 agonists. Direct head-to-head comparisons against semaglutide or tirzepatide in Chinese populations have been reported in conference abstracts but full Phase 3 head-to-head data is limited. The clinical positioning is as a competitive alternative with potentially distinct metabolic profile (hepatic fat focus) rather than as a direct replacement for established incretins.

The Phase 3 program in the United States and EU is at an earlier stage. Lilly is conducting global development independently of the Innovent Chinese commercial program.

Mazdutide activates both glucagon and GLP-1 receptors with engineered relative potency. The dual mechanism produces effects that exceed those of single-receptor GLP-1 agonists.

GLP-1 receptor activation. Standard incretin effects: appetite suppression through hypothalamic and brainstem signaling, slowed gastric emptying, glucose-dependent insulin secretion, reduced glucagon release in pancreatic alpha cells. The same set of effects produced by semaglutide and liraglutide.

Glucagon receptor activation. This is the differentiating mechanism. Glucagon receptor activation increases hepatic glucose production under normal physiology (the reason glucagon is used to treat hypoglycemia). When paired with strong GLP-1 activity that suppresses the appetite that would compensate for the glucagon effect, the net result is increased energy expenditure and hepatic lipid oxidation without hyperglycemia. The glucagon component drives liver fat reduction, lipid metabolism improvements, and additional weight-loss contribution that GLP-1 alone does not produce.

Combined metabolic effects. Beyond weight loss, mazdutide has shown reductions in waist circumference, blood lipids, blood pressure, serum uric acid, liver enzymes, and liver fat content, with improved insulin sensitivity. The breadth of metabolic effects exceeds the GLP-1-only class.

Mechanistic distinction from tirzepatide and retatrutide. Tirzepatide pairs GLP-1 with GIP. Mazdutide pairs GLP-1 with glucagon. Retatrutide combines GLP-1, GIP, and glucagon (the triple agonist). Each combination produces somewhat different metabolic profiles, with the GLP-1/glucagon combination particularly relevant for hepatic fat metabolism and energy expenditure.

The fatty-acyl modification enables once-weekly subcutaneous dosing through albumin binding, similar to the mechanism in semaglutide and liraglutide.

Regulatory status

China. NMPA approval for chronic weight management on June 27, 2025. NMPA approval for type 2 diabetes added in September 2025. Marketed as Xinermei by Innovent Biologics.

United States. Phase 2 development by Eli Lilly. No NDA submitted at the time of writing.

EU and rest of world. Lilly holds global rights outside China and is conducting independent global development. No EMA submission has been announced.

WADA status. Mazdutide is not currently named on the WADA Prohibited List as a specific substance. It would fall under section S4 (Hormone and Metabolic Modulators) by analogy with other GLP-1 agonists, which require Therapeutic Use Exemption for competitive sport.

Dosing protocols and literature-reported ranges are documented in the approved label or trial publications referenced above.

The Phase 3 safety data from GLORY-1 and DREAMS-2 has been consistent with the incretin class profile.

Gastrointestinal effects dominate. Nausea, diarrhea, constipation, and vomiting during dose escalation. The glucagon receptor activation may contribute to subtly different GI tolerability than pure GLP-1 agonists.

Mild hypoglycemia risk in T2D patients on concurrent insulin or sulfonylureas.

Injection-site reactions common but mild.

No new safety signals beyond the established GLP-1 and glucagon receptor pharmacology have been reported.

Mild heart rate increase consistent with GLP-1 class effects.

The dual receptor activity has not produced unexpected adverse effects in the Chinese trial program. The Phase 3 safety database supported NMPA approval for both obesity and diabetes indications.

The incretin agonist class has expanded substantially in the 2020s.

Mazdutide (GLP-1/GCG). First-in-class dual GCG/GLP-1 agonist. NMPA-approved June 2025. Distinguished by glucagon receptor activity that supports hepatic fat metabolism and energy expenditure. US development at Phase 2.

Semaglutide (GLP-1 alone). FDA-approved for diabetes, obesity, cardiovascular risk, and chronic kidney disease. The reference single-agonist incretin.

Tirzepatide (GLP-1/GIP). FDA-approved for diabetes (Mounjaro), obesity (Zepbound), and obstructive sleep apnea. Approximately 22 percent mean weight loss in SURMOUNT-1. The reference dual-agonist incretin.

Retatrutide (GLP-1/GIP/GCG triple agonist). Phase 3, FDA approval anticipated late 2027. Approximately 28.7 percent mean weight loss in TRIUMPH-4. Combines all three incretin/glucagon pathways.

Survodutide (GLP-1/GCG). Boehringer Ingelheim/Zealand Pharma competitor to mazdutide. Phase 3 SYNCHRONIZE-1 reported 16.6 percent weight loss. Different commercial sponsor, similar mechanism class.

For practical positioning in the obesity space, mazdutide is the first dual GCG/GLP-1 approval anywhere in the world and validates the mechanism. Survodutide is the direct competitor in the same class with active global Phase 3. Whether these compounds expand to FDA and EMA approval in 2026 to 2027 will define the second wave of incretin-class obesity therapeutics.