Guides · PeptideU · 9 min read

Mazdutide Results Timeline: What Studies Measured, and When

The short answer

Published mazdutide trials assessed outcomes at fixed, pre-specified timepoints rather than at arbitrary "results" milestones. Phase 1 work examined multiple ascending and high doses, phase 2 trials measured body weight at week 24 and HbA1c at week 20, and a phase 3 obesity trial measured percentage weight change at week 32 with treatment continuing to week 48. Later phase 3 diabetes trials compared mazdutide with placebo and with dulaglutide. Reviews and meta-analyses pooled these results. This page reports what was measured, not what any individual should expect.

Questions about a "results timeline" for mazdutide are, in the published literature, questions about trial design. Investigators chose in advance when to weigh participants, when to draw blood for glycated haemoglobin (HbA1c), and how long to continue treatment. Those pre-specified timepoints — not individual experience — are what the papers below describe. This page summarises what each study measured, in whom, and at which week, and it avoids any claim about what a given person would observe.

What mazdutide is, as the literature describes it

Mazdutide (also identified as IBI362) was characterised as a dual glucagon-like peptide-1 (GLP-1) and glucagon receptor agonist in a phase 1b multiple-ascending-dose trial in Chinese adults with overweight or obesity (PMID 36247927). A 2026 Endocrine Reviews overview discussed mazdutide among novel GLP-1-based medications for type 2 diabetes and obesity (PMID 41054801), and a 2025 systematic review in Pharmacological Reviews catalogued it among emerging pharmacotherapies for obesity (PMID 39952695).

Why "when" depends on the protocol

Weekly-dosed agents in this class are typically escalated gradually, so the week at which a trial reports its primary endpoint reflects a protocol decision about escalation and maintenance. The phase 2 obesity trial in Chinese adults, for example, assessed percentage change in body weight after 24 weeks of treatment (PMID 38092790), while the phase 3 obesity trial published in The New England Journal of Medicine assessed percentage change in body weight at week 32 and continued treatment through week 48 (PMID 40421736). Comparing "week 24" in one study to "week 32" in another therefore compares two different protocols, populations and dose ranges.

Trials and the timepoints they used

Study (type)	Population studied	Doses reported	Timepoints described
Phase 1b, randomised, placebo-controlled, multiple ascending dose (PMID 36247927)	Chinese adults with overweight or obesity	9 mg and 10 mg	Safety and efficacy assessed across the multiple-ascending-dose schedule
High-dose phase 1 trial (PMID 40832785)	Adults with overweight or obesity	High-dose regimen, as reported by the study	Body weight change reported within the phase 1 trial period
Phase 2 randomised controlled trial (PMID 38092790)	Chinese overweight adults or adults with obesity	3.0 mg, 4.5 mg and 6.0 mg weekly	Percentage change in body weight at week 24
Phase 2 randomised, double-blind, placebo-controlled trial (PMID 37943529)	Chinese patients with type 2 diabetes	3.0 mg, 4.5 mg and 6.0 mg weekly	Change in HbA1c at week 20
Phase 3, once-weekly mazdutide (PMID 40421736)	Chinese adults with obesity or overweight	4 mg and 6 mg weekly	Percentage change in body weight at week 32; treatment continued to week 48
Mazdutide versus placebo (PMID 41407859)	Chinese adults with type 2 diabetes	As reported by the trial	Placebo-controlled comparison
Mazdutide versus dulaglutide (PMID 41407860)	Chinese adults with type 2 diabetes	As reported by the trial	Active-comparator comparison

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The earliest human timepoints: phase 1

The first human signals came from small early-phase work. Researchers conducting a randomised, placebo-controlled, multiple-ascending-dose phase 1b trial reported on the safety and efficacy of mazdutide 9 mg and 10 mg in Chinese adults with overweight or obesity (PMID 36247927). A separate high-dose phase 1 trial reported reductions in body weight in adults with overweight or obesity (PMID 40832785).

Early-phase trials of this kind enrol small numbers of participants and are designed primarily around safety, tolerability and pharmacokinetics; the weight findings described in the high-dose phase 1 report should be read in that context (PMID 40832785). They do not establish what happens over a year, and the phase 1b report was explicitly framed as a dose-exploration study (PMID 36247927).

Weeks 20 to 24: the phase 2 window

Two phase 2 trials anchor the mid-range of the published timeline. In Chinese overweight adults or adults with obesity, the study evaluated mazdutide 3.0 mg, 4.5 mg and 6.0 mg weekly and measured percentage change in body weight at week 24 (PMID 38092790). In Chinese patients with type 2 diabetes, a randomised, double-blind, placebo-controlled phase 2 trial evaluated the same weekly dose levels and measured change in HbA1c at week 20 (PMID 37943529).

The distinction matters for anyone reading the timeline literally: the obesity trial's headline number described body weight after 24 weeks (PMID 38092790), whereas the diabetes trial's headline number described a glycaemic measure after 20 weeks (PMID 37943529). HbA1c reflects average glycaemia over preceding weeks, which is one reason glycaemic endpoints in this field are commonly placed at or after roughly 20 weeks rather than earlier, as in that trial's design (PMID 37943529).

Dose levels varied between phases

The phase 2 programme used 3.0 mg, 4.5 mg and 6.0 mg weekly in both the obesity (PMID 38092790) and type 2 diabetes settings (PMID 37943529), while the phase 1b work explored 9 mg and 10 mg (PMID 36247927) and the phase 3 obesity trial used 4 mg and 6 mg once weekly (PMID 40421736). Results at a given week are therefore not interchangeable across studies.

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Weeks 32 and 48: the phase 3 obesity timeline

The largest published obesity dataset came from a phase 3 trial of once-weekly mazdutide 4 mg and 6 mg in Chinese adults with obesity or overweight, in which researchers measured percentage change in body weight at week 32 and continued treatment through week 48 (PMID 40421736). That two-stage structure — a primary assessment followed by a longer treatment period — is why some summaries of the same trial quote a week 32 figure and others quote a week 48 figure (PMID 40421736).

Phase 3 in type 2 diabetes: placebo and active comparison

Two 2026 Nature reports extended the diabetes evidence. One compared mazdutide with placebo in Chinese adults with type 2 diabetes (PMID 41407859), and the other compared mazdutide with dulaglutide in Chinese adults with type 2 diabetes (PMID 41407860). An active-comparator design answers a different question from a placebo-controlled design, because the reference group also received an active agent (PMID 41407860).

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What reviews and meta-analyses pooled

Several evidence syntheses combined mazdutide trials across these timepoints. A 2024 systematic review and meta-analysis of randomised controlled trials in Frontiers in Endocrinology examined the efficacy and safety of mazdutide on weight loss among diabetic and non-diabetic patients (PMID 38440786). An updated systematic review and network meta-analysis in Metabolism placed mazdutide among seven GLP-1 receptor agonists and polyagonists assessed for weight loss in patients with obesity or overweight (PMID 39305981).

Narrative and mechanistic reviews framed the same body of work more broadly: the 2025 Pharmacological Reviews systematic review of emerging obesity pharmacotherapies (PMID 39952695), a 2026 Endocrine Reviews article on novel GLP-1-based medications for type 2 diabetes and obesity (PMID 41054801), and a 2026 Lancet Diabetes & Endocrinology review of multisystem effects of obesity medications beyond weight loss (PMID 42208956). Pooled estimates in such syntheses average across trials with different durations and dose ranges, a limitation acknowledged in the network meta-analysis itself (PMID 39305981).

Adverse Events Across the Timeline: What Studies Report

Tolerability findings were reported alongside efficacy in the same trials. The phase 3 trial of once-weekly mazdutide in Chinese adults with obesity or overweight reported gastrointestinal adverse events as the most common adverse events observed (PMID 40421736). The phase 2 randomised controlled trial in Chinese overweight adults or adults with obesity likewise reported that adverse events were predominantly gastrointestinal (PMID 38092790), and the phase 2 trial in Chinese patients with type 2 diabetes reported safety outcomes as part of its pre-specified assessment (PMID 37943529).

The 2024 systematic review and meta-analysis also assessed safety alongside weight outcomes across the randomised controlled trials it pooled (PMID 38440786), and the phase 1b multiple-ascending-dose trial reported safety at 9 mg and 10 mg (PMID 36247927). Adverse-event frequencies reported in trials reflect the specific escalation schedules and populations studied, not any general expectation.

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What the published timeline does not settle

Durations beyond the trial windows. The longest obesity timepoint described in the phase 3 report was week 48 (PMID 40421736); multi-year outcomes were not part of that report.
Generalisability. The phase 2 and phase 3 obesity and diabetes trials cited here enrolled Chinese adults (PMID 38092790, PMID 41407859).
Individual trajectories. Trials reported group-level means and endpoint comparisons, as in the phase 3 obesity trial's week 32 analysis (PMID 40421736); group means do not describe any one participant.
Non-weight outcomes. Broader organ-system effects of obesity medications were discussed at review level rather than established for mazdutide specifically (PMID 42208956).

Reading a timeline without over-reading it

Across the verified literature, the pattern is consistent: early-phase trials explored dose levels such as 9 mg and 10 mg (PMID 36247927), phase 2 trials reported at weeks 20 and 24 (PMID 37943529, PMID 38092790), and phase 3 reported at week 32 with treatment to week 48 (PMID 40421736). The evidence describes measurement schedules, not promises.

This page is for educational purposes only and is not medical advice; consult a licensed physician or qualified healthcare professional about any medical condition, medication or treatment decision.

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References

Frequently asked questions

At which week did the phase 3 obesity trial measure body weight?▾

Researchers measured percentage change in body weight at week 32 in the phase 3 trial of once-weekly mazdutide 4 mg and 6 mg in Chinese adults with obesity or overweight, with treatment continuing through week 48 (PMID 40421736). Summaries quoting different figures for the same trial usually reflect those two separate timepoints rather than different studies.

What timepoint did the phase 2 obesity trial use?▾

The study, a phase 2 randomised controlled trial in Chinese overweight adults or adults with obesity, evaluated mazdutide 3.0 mg, 4.5 mg and 6.0 mg weekly and measured percentage change in body weight at week 24 (PMID 38092790). That 24-week window is shorter than the phase 3 obesity trial's primary assessment at week 32 (PMID 40421736).

When was HbA1c assessed in the diabetes trials?▾

In a randomised, double-blind, placebo-controlled phase 2 trial in Chinese patients with type 2 diabetes, researchers reported change in HbA1c at week 20 using weekly doses of 3.0 mg, 4.5 mg and 6.0 mg (PMID 37943529). Later phase 3 work compared mazdutide with placebo (PMID 41407859) and with dulaglutide (PMID 41407860) in Chinese adults with type 2 diabetes.

Is there evidence from very early, short trials?▾

Yes. A randomised, placebo-controlled, multiple-ascending-dose phase 1b trial reported safety and efficacy of mazdutide 9 mg and 10 mg in Chinese adults with overweight or obesity (PMID 36247927), and a separate high-dose phase 1 trial reported body weight reduction in adults with overweight or obesity (PMID 40832785). Early-phase trials are small and focused on safety and dose exploration.

What do the meta-analyses add about timing?▾

A 2024 systematic review and meta-analysis of randomised controlled trials examined mazdutide's efficacy and safety for weight loss among diabetic and non-diabetic patients (PMID 38440786), and a network meta-analysis compared seven GLP-1 receptor agonists and polyagonists for weight loss in obesity or overweight (PMID 39305981). Pooled estimates average trials of differing durations and doses, so they blur individual timepoints.

When were adverse events most commonly reported?▾

The phase 3 trial reported gastrointestinal adverse events as the most common adverse events observed (PMID 40421736), and the phase 2 obesity trial likewise reported predominantly gastrointestinal events (PMID 38092790). Safety was also assessed in the phase 1b multiple-ascending-dose trial at 9 mg and 10 mg (PMID 36247927). Frequencies reflect the specific protocols and populations studied.

Do these trials show what happens after a year?▾

No. The longest obesity timepoint described in the phase 3 report was week 48 (PMID 40421736), and phase 2 trials reported at weeks 20 and 24 (PMID 37943529, PMID 38092790). Reviews of novel GLP-1-based medications discuss the broader field (PMID 41054801), but multi-year mazdutide outcomes were not part of the trials cited here.

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References

18+ · Educational purposes only
This page summarises published research for education — it is not medical advice, and nothing here is a recommendation to use, purchase, or dose any substance. Study parameters described are what researchers reported, not instructions. Consult a qualified clinician before any health decision.