Mazdutide Guide & Tableau de Dose

What is Mazdutide?

Mazdutide — also called IBI362 or LY3305677 — is a research peptide being studied for weight loss and metabolic health. It was developed by Innovent Biologics and is given as a once-weekly injection under the skin. Most clinical trials so far have been conducted in Chinese adults.^[1] It belongs to a fast-growing class of obesity medicines called incretin-based dual agonists.^[2] That's a mouthful, but the concept is straightforward: the molecule targets two hormone receptors at once to tackle excess body weight from more than one angle.

How Mazdutide Works

Think of your metabolism as a thermostat. Two hormones — GLP-1 (glucagon-like peptide-1) and glucagon — act like dials on that thermostat. GLP-1 tells your brain you're full and slows the speed at which food leaves your stomach, making you eat less. Glucagon, when activated in a controlled way, nudges your body to burn more calories and break down stored fat for energy — a bit like turning up the heat.

Mazdutide mimics both signals at the same time.^[4] The GLP-1 side reduces appetite; the glucagon side may boost energy expenditure. Together, researchers believe this one-two punch could produce stronger weight loss than targeting either receptor alone.^[3] Because it's designed as a long-acting molecule given just once a week, blood levels stay relatively steady without daily injections.

What the Research Shows

Phase 1b — Early Dose-Finding Studies

The first published human trials tested escalating doses in small groups of Chinese adults with overweight or obesity. In one phase 1b study, participants received doses from 1.5 mg up to 6 mg once weekly over 12 weeks. Researchers found the compound was generally well tolerated, with mostly mild-to-moderate gastrointestinal side effects like nausea and decreased appetite.^[4]

A follow-up phase 1b trial pushed the dose higher — up to 9 mg and 10 mg. In the 9 mg group, people lost an average of 11.7% of their body weight in just 12 weeks, compared with 1.8% for placebo. The 10 mg group showed a 9.5% loss over 16 weeks versus 3.3% for placebo. No serious adverse events were reported in either cohort, and the side-effect profile remained largely gastrointestinal.^[3]

Phase 2 — Bigger, Longer

A randomised, controlled phase 2 trial in Chinese adults with overweight or obesity tested multiple doses of mazdutide over 24 weeks. Results confirmed dose-dependent weight loss — the more drug, the more weight lost — with a safety profile consistent with what earlier studies found.^[5]

Phase 3 — The GLORY-1 Trial

The biggest and most rigorous study so far is the GLORY-1 phase 3 trial, published in the New England Journal of Medicine in 2025.^[1] It enrolled 610 Chinese adults with a BMI of 28 or higher (or BMI 24–28 with a weight-related health condition). Participants were randomly assigned to 4 mg mazdutide, 6 mg mazdutide, or placebo — all once weekly for 48 weeks.

• At 48 weeks, the 4 mg group lost an average of 11.0% of body weight vs. 0.3% for placebo.^[1]
• The 6 mg group lost an average of 14.0% of body weight vs. 0.3% for placebo.^[1]
• Nearly 50% of the 6 mg group lost at least 15% of their body weight by week 48, compared with just 2% on placebo.^[1]
• Mazdutide also produced improvements across all pre-specified cardiometabolic measures — things like blood pressure, waist circumference, and blood lipids.^[1]
• Gastrointestinal events (nausea, diarrhoea, vomiting) were the most common side effects and were mostly mild to moderate. The rate of stopping the drug due to side effects was low: 1.5% at 4 mg, 0.5% at 6 mg.^[1]

How It Compares to Other Weight-Loss Peptides

A 2024 network meta-analysis that pooled data from randomised trials of seven GLP-1 receptor agonists and related compounds included mazdutide among the most effective agents reviewed for percentage weight loss in people with overweight or obesity.^[6] A broader 2025 systematic review also identified mazdutide as one of the GLP-1/glucagon dual agonists in active phase 3 development — part of a rapidly expanding obesity drug pipeline.^[2]

What Mazdutide Is Being Studied For

• Weight loss / obesity — the primary focus of all current trials^[1]
• Overweight with metabolic risk factors — e.g., high blood pressure or abnormal lipids^[1]
• Type 2 diabetes — mentioned as a development target given the GLP-1 mechanism^[4]
• Broader cardiometabolic outcomes — improvements in blood pressure, lipids, and waist circumference have been documented in trials, though dedicated cardiovascular outcome trials have not yet been published^[1]

All uses listed here are investigational. Mazdutide is a research compound, not an approved medicine.

How Mazdutide Is Dosed in Research

Research trials have used a dose-escalation approach — starting low and stepping up every few weeks — to help the body adjust and reduce gastrointestinal side effects. The specific doses and schedules used across phase 1b, phase 2, and phase 3 studies are summarised in the dosage chart on this page. For a quick lookup tool, try the interactive calculator. All doses have been administered as once-weekly subcutaneous injections. Research doses have ranged from 2.5 mg all the way up to 10 mg per week depending on the trial cohort, with 4 mg and 6 mg as the two doses evaluated in the landmark phase 3 GLORY-1 trial.^[1]

Mixing and Storing Mazdutide

Mazdutide used in clinical trials is supplied as a pre-filled, ready-to-inject solution — no powder to dissolve. For research laboratory settings where a lyophilised (freeze-dried) powder form might be handled, the general principles for GLP-1 class peptides apply: reconstitute with the volume of sterile bacteriostatic water specified on the vial label, swirl gently (never shake), and allow the solution to sit until fully clear. Use a fresh, sterile syringe each time. Store unreconstituted powder in a freezer away from light; once mixed, keep refrigerated at 2–8 °C (36–46 °F) and use within the manufacturer's stated window — typically 28 days. Never freeze a reconstituted solution, as this can degrade the peptide. Always inspect for particles or cloudiness before use and discard if present. These are general laboratory handling guidelines; always follow the specific instructions provided with your research-grade material.

Sources

1. Once-Weekly Mazdutide in Chinese Adults with Obesity or Overweight. — The New England journal of medicine, 2025. PMID 40421736.
2. Emerging pharmacotherapies for obesity: A systematic review. — Pharmacological reviews, 2025. PMID 39952695.
3. Safety and efficacy of a GLP-1 and glucagon receptor dual agonist mazdutide (IBI362) 9 mg and 10 mg in Chinese adults with overweight or obesity: A randomised, placebo-controlled, multiple-ascending-dose phase 1b trial. — EClinicalMedicine, 2022. PMID 36247927.
4. IBI362 (LY3305677), a weekly-dose GLP-1 and glucagon receptor dual agonist, in Chinese adults with overweight or obesity: A randomised, placebo-controlled, multiple ascending dose phase 1b study. — EClinicalMedicine, 2021. PMID 34430840.
5. A phase 2 randomised controlled trial of mazdutide in Chinese overweight adults or adults with obesity. — Nature communications, 2023. PMID 38092790.
6. Seven glucagon-like peptide-1 receptor agonists and polyagonists for weight loss in patients with obesity or overweight: an updated systematic review and network meta-analysis of randomized controlled trials. — Metabolism: clinical and experimental, 2024. PMID 39305981.