Mazdutide: The GLP-1/Glucagon Dual Agonist Approved in China

At a Glance

Mazdutide makes the “which second receptor?” question concrete. Tirzepatide proved that adding GIP agonism to GLP-1 deepens weight loss. Mazdutide takes the other available route — glucagon receptor agonism — and it reached approval first, in China, where it is sold as Xinermei.

The honest verdict: mazdutide works, with phase 3 weight loss in the 14–17% range and a US phase 2 result of 18.1% at 32 weeks on 16 mg, placing it credibly between semaglutide and tirzepatide. Whether it is actually better than tirzepatide is unknown, because no head-to-head exists and the Chinese trials enrolled a population with substantially lower baseline weight than SURMOUNT or STEP. Its distinctive promise is metabolic rather than purely anthropometric: glucagon agonism drives hepatic fat oxidation and raises energy expenditure, which shows up as strong waist and cardiometabolic effects.

For patients outside China the practical status is simple: this is a drug to watch, not one to obtain. Material sold online as “mazdutide” is research-chemical supply with none of the quality assurances the approved Chinese product carries.

How it works

Mazdutide is based on oxyntomodulin, a naturally occurring proglucagon-derived peptide that activates both the GLP-1 and the glucagon receptor. The molecule is engineered for weekly dosing and biased towards GLP-1 over glucagon receptor activity.

The two arms do different jobs:

• GLP-1 receptor agonism reduces appetite and energy intake, improves glucose-dependent insulin secretion and slows gastric emptying — the same mechanism as semaglutide.
• Glucagon receptor agonism increases resting energy expenditure, stimulates hepatic lipolysis and fatty acid oxidation, and reduces hepatic steatosis. Glucagon is classically the hormone that raises blood glucose, so pairing it with a GLP-1 agonist only works because the GLP-1 arm more than compensates.

That pairing is the central design trade-off of the whole GLP-1/glucagon class, which includes mazdutide, survodutide and the glucagon arm of retatrutide. You gain energy expenditure and liver-fat mobilisation; you accept a hormone that is theoretically catabolic and can raise heart rate, and you need the GLP-1 component to hold glucose in check. In the mazdutide diabetes trials the glycaemic result was strongly positive, which settles that question in practice [5, 7].

What the evidence shows

Obesity: the GLORY programme

GLORY-1 (Ji, NEJM 2025) randomised 610 Chinese adults — BMI ≥28, or 24 to <28 with a weight-related condition; mean weight 87.2 kg, mean BMI 31.1 — to mazdutide 4 mg, 6 mg or placebo for 48 weeks. At week 32, weight change was −10.09% (4 mg), −12.55% (6 mg) and +0.45% (placebo), with ≥5% weight loss in 73.9%, 82.0% and 10.5%. At week 48: −11.00%, −14.01% and +0.30%, with ≥15% weight loss in 35.7%, 49.5% and 2.0%. Discontinuation for adverse events was strikingly low — 1.5%, 0.5% and 1.0% [2].

GLORY-2 (Gao, JAMA 2026) tested 9 mg in 461 Chinese adults with BMI ≥30 (mean BMI 34.3, mean age 33.9, 16% with type 2 diabetes) over 60 weeks. Mean weight change was −16.65% versus −1.50% on placebo (between-group difference −15.15%), and 84.3% versus 33.1% lost at least 5%. Adverse events were predominantly gastrointestinal — vomiting 53.1%, nausea 46.9%, diarrhoea 39.4% — with 2.9% discontinuing [3].

Phase 2 in China (Ji, Nat Commun 2023) established the dose-response: at 24 weeks, −6.7% (3 mg), −10.4% (4.5 mg), −11.3% (6 mg) versus +1.0% on placebo [1].

US phase 2 (Hsia, Lancet Diabetes Endocrinol 2026) is the most important trial for anyone outside China: 179 US adults without diabetes randomised to placebo or mazdutide 3–6 mg, 10 mg or 16 mg for 48 weeks. At 32 weeks, least-squares mean weight change was −7.3% (3–6 mg), −15.6% (10 mg) and −18.1% (16 mg) versus −0.9% on placebo, with further reductions by week 48. Discontinuation for adverse events was highest at 16 mg (20%), mostly gastrointestinal [4]. Two things stand out: the doses needed in a US population were well above those approved in China, and tolerability at 16 mg was the limiting factor.

High-dose phase 1 (Bhattachar, Diabetes Obes Metab 2025) reported mean weight change of −20.0% and −21.0% in two high-dose cohorts at week 20 versus −0.1% on placebo, with waist reductions of 12–17% [8]. Small and early, but an indication of where the dose-response ceiling may sit.

Type 2 diabetes: the DREAMS programme

Versus placebo (Zhu, Nature 2026): 320 Chinese adults with type 2 diabetes inadequately controlled on diet and exercise, randomised to 4 mg, 6 mg or placebo for 24 weeks. HbA1c fell 1.57% and 2.15% versus 0.14% on placebo; weight fell 5.61% and 7.81% versus 1.26% [5].

Versus dulaglutide (Guo, Nature 2026, DREAMS-2) is the active-comparator phase 3 in Chinese adults with type 2 diabetes [6]. The earlier phase 2 (Zhang, Diabetes Care 2024) had already shown HbA1c reductions of 1.41–1.67% with mazdutide versus 1.35% with dulaglutide and +0.03% with placebo at week 20, with weight loss up to −7.1% versus −2.7% and −1.4% [7].

What is missing

No head-to-head against tirzepatide or semaglutide. No cardiovascular outcome trial. No liver-biopsy trial. No data beyond 60 weeks. And a population question that is easy to overlook: GLORY-1 enrolled at a mean BMI of 31.1 where SURMOUNT-1 enrolled at 38.0, and percentage weight loss does not transfer automatically between those populations.

Dosing

For informational purposes only — this summarises doses used in research and practice; it is not a prescription or individual medical advice.

Titration is where this drug lives or dies. The contrast between GLORY-1 (0.5–1.5% discontinuation at 4–6 mg) and the US trial (20% at 16 mg) is almost entirely a dose and escalation-speed story. If mazdutide reaches Western markets, slow escalation with a maintenance dose below the ceiling is the regimen I would expect.

Stacks and combinations commonly used. In the diabetes trials mazdutide was studied as monotherapy or on a background of oral agents; combination with insulin or a sulfonylurea means reducing those first. Lean-mass and protein considerations are the same as for the rest of the class — see preserving muscle on GLP-1 therapy. Injection technique: peptide injection guide.

What people report: what works and what doesn’t

Mazdutide has only been in real-world use since mid-2025, almost entirely in China, so the anecdotal base is thin. Sources: the trials above; the open community record on r/Peptides; and published reviews of the multi-receptor agonist class. Patterns only — no individual account is treated as evidence.

Reported to work

• Appetite suppression similar in character to other weekly agents in this class, with weight loss in the low-to-mid teens as a percentage over the first year, consistent with GLORY-1 and GLORY-2 [2, 3].
• Visible waist reduction, sometimes described as disproportionate to the weight change. The trials emphasise the same thing — waist fell 12–17% in the high-dose phase 1 cohorts [8] — and it is what the glucagon arm predicts.
• Warmth and energy during the first weeks, consistent with increased energy expenditure, though this is exactly the kind of subjective effect placebo produces readily.

Mixed or unclear

• Resting heart rate. Glucagon receptor agonism can raise it; trial reports do not flag it as limiting, and community reports are inconsistent.
• Whether mazdutide outperforms semaglutide for a given person. Without a head-to-head this is unanswerable, and indirect comparison across populations differing by seven BMI points is unreliable.
• Liver effects: mechanistically plausible, reported as improved liver enzymes, no biopsy-based trial.

Reported not to work / disappointing

• Tolerability at high doses — the dominant complaint, and the trial data agree: vomiting in half of participants at 9 mg [3], one in five discontinuing at 16 mg [4].
• Expecting tirzepatide-level results from the approved Chinese doses. The 4–6 mg regimen produces 11–14%, not 21%.
• Grey-market sourcing. Mazdutide is new enough that vendor supply is unverified in identity and concentration, and inconsistent potency is the predictable consequence — see peptide sourcing.

What a properly designed trial would need to show next: a head-to-head against tirzepatide at tolerable maintenance doses in a Western population, a cardiovascular outcome trial, and biopsy-confirmed liver histology. All three are the obvious next steps; none has reported.

Safety and side effects

Common. Diarrhoea, nausea, vomiting, decreased appetite, constipation, upper respiratory infection, injection-site reactions. The GI profile is the standard incretin pattern, and at 9 mg it is heavy: vomiting 53%, nausea 47%, diarrhoea 39% in GLORY-2 [3].

Dose-related tolerability. Discontinuation for adverse events ranged from 0.5–1.5% at 4–6 mg in GLORY-1 [2] to 20% at 16 mg in the US trial [4]. This is the single most important safety number for the drug.

Glucagon-specific considerations. Glucagon receptor agonism can increase heart rate and resting energy expenditure and, in principle, affects hepatic glucose output and protein catabolism. Trial reports have not identified these as dose-limiting, but they are the reasons to monitor pulse, liver enzymes and lean mass, and the reason this class is not a casual choice in anyone with sarcopenia or arrhythmia.

Hypoglycaemia. Reported in 10% versus 8% with placebo in the phase 2 diabetes trial [7] — not an independent risk, but combination with insulin or a sulfonylurea changes that.

Contraindications, by class analogy. Personal or family history of medullary thyroid carcinoma or MEN2, prior pancreatitis, pregnancy and breastfeeding, severe gastroparesis. Mazdutide’s own label is Chinese; the class cautions apply.

Sourcing. Approved mazdutide exists in exactly one market. Anything bought elsewhere is research-chemical material of unverified identity, concentration and sterility.

Legal and regulatory status

China. Approved by the NMPA in June 2025 for chronic weight management in adults with overweight or obesity and at least one weight-related comorbidity, marketed by Innovent as Xinermei. A separate type 2 diabetes application was filed on the strength of the phase 3 diabetes programme.

United States. Not approved. Eli Lilly holds rights outside China and has completed the phase 2 trial above. Mazdutide does not appear in the FDA 503A category 1 list, so compounding is not covered by the interim enforcement policy — see the FDA 2026 compounding update.

European Union and Germany. No EMA marketing authorisation, and no pharmacy-grade supply. Importing it for personal use is legally exposed.

Sport. Where a substance has no approval in the athlete’s jurisdiction, WADA’s S0 category applies — prohibited at all times. See peptides and WADA rules.

How it fits: the two ways to build a dual agonist

Mazdutide’s clinical identity is the glucagon arm. If what you most want to move is hepatic fat, waist circumference and energy expenditure rather than the scale alone, the GLP-1/glucagon design is the mechanistically appropriate one — and retatrutide’s triple-agonist results suggest the glucagon contribution is real rather than cosmetic.

What keeps it a watch-list drug outside China is not efficacy but evidence fit: a lower-BMI pivotal population, no cardiovascular outcomes, no liver histology, and no head-to-head against the agent that currently defines the ceiling. If the 10–16 mg doses go into Western phase 3 trials with slower escalation, this becomes a genuine competitor. Until then, the honest answer to “should I take mazdutide?” outside China is that there is no legitimate way to do so.

Related Articles

• Tirzepatide: The Dual GIP/GLP-1 Agonist in Full — the other way to build a dual agonist.
• Retatrutide vs Semaglutide vs Tirzepatide — where the glucagon arm appears in a triple agonist.
• Eloralintide: The Selective Amylin Agonist — the non-incretin pathway now entering phase 3.
• Semaglutide: Beyond Weight Loss — A Physician’s Assessment — the GLP-1-only benchmark.
• Preserving Muscle on Semaglutide and Tirzepatide — relevant to any agent with a catabolic component.
• Peptide Sourcing: Pharmaceutical-Grade vs Grey Market — why a China-only approval matters for what you can actually buy.