Primary Description

Also known as:IBI362LY3305677OXM dual agonistNot publicly disclosed (proprietary fatty-acyl modified peptide)

Mazdutide is a once-weekly subcutaneous GLP-1/glucagon receptor (GCGR) dual agonist derived from oxyntomodulin, originally developed by Innovent Biologics and licensed to Eli Lilly. It received its first regulatory approval from China's NMPA in 2025 for chronic weight management. Community interest is growing rapidly as Phase 3 data show superior weight loss and glycemic control versus semaglutide, though Western market access and community use data remain limited compared to older GLP-1 agents.

Key Benefits

Dual GLP-1/GCGR agonist — fat burning + glucose control in a single molecule
Greater weight loss than GLP-1 alone in Phase 2 data (GLORY trial: -14.4% at 24 weeks)
Improved lipid profile and liver steatosis via glucagon receptor signaling

Storage & Stability

Lyophilized: stable at -20C long-term. Reconstituted: refrigerate at 2-8C; use within manufacturer guidelines. Weekly dosing supported by extended half-life of 6-28 days depending on dose.

Demonstrated Effects

Significant body weight reduction: ~11-15% at Phase 3 doses (4-6 mg/week), up to -20% at high-dose Phase 1 (16 mg/week)
Superior glycemic control vs. semaglutide (DREAMS-3 head-to-head: -2.03% HbA1c vs. -1.84%)
Greater visceral fat reduction than GLP-1-only agents due to glucagon receptor-mediated thermogenesis
Appetite suppression and reduced caloric intake via GLP-1R pathway
Increased energy expenditure via glucagon receptor activation (thermogenic effect)
Improved insulin sensitivity and lipid profiles
Emerging data: neuroprotective effects and cognitive improvement in diabetic models (2025, eBioMedicine)
Favourable safety profile — lowest dropout rate among next-gen GLP-1 class in comparative analysis

Proposed Mechanisms of Action

Proposed mechanisms based on available research

1. GLP-1 Receptor Agonism

Description

Activates GLP-1R on pancreatic beta cells, gut, and brain — stimulating glucose-dependent insulin secretion, suppressing glucagon from alpha cells, slowing gastric emptying, and reducing appetite via hypothalamic signaling.

Practical Impact

Drives the glycemic control, appetite suppression, and weight loss components of mazdutide's profile.

2. Glucagon Receptor Agonism (GCGR)

Description

Activates hepatic glucagon receptors to stimulate glycogenolysis and gluconeogenesis in a controlled manner, while also increasing energy expenditure via thermogenesis and enhanced fatty acid oxidation. The balance with GLP-1R agonism prevents net hyperglycemia.

Practical Impact

Differentiates mazdutide from pure GLP-1 agonists by adding a thermogenic and energy-expenditure component, contributing to greater fat loss.

3. Oxyntomodulin Mimicry

Description

Mazdutide is a structural analogue of oxyntomodulin (OXM), an endogenous gut hormone that naturally activates both GLP-1R and GCGR. A fatty-acyl modification extends its half-life to support weekly dosing.

Practical Impact

Provides a physiologically grounded dual-receptor mechanism with extended pharmacokinetics suitable for once-weekly subcutaneous injection.

Research Evidence & Clinical Data

Review of available research evidence and clinical data

Investigated Applications

Weight Management / Obesity

Anecdotal: Emerging

Community reports are sparse compared to semaglutide/tirzepatide but growing. Early adopters report strong appetite suppression and faster plateau-breaking than semaglutide alone, attributed to the dual thermogenic mechanism. Most current use is in clinical trial settings in China.

Preclinical basis: Phase 3 GLORY-1: -14.31% weight vs. placebo at 48 weeks. DREAMS-3 head-to-head vs. semaglutide: mazdutide superior on combined weight + glycemic endpoints.

Type 2 Diabetes / Glycemic Control

Anecdotal: Emerging

Phase 2 and Phase 3 trials demonstrate robust HbA1c reduction. Community metabolic biohackers combine with CGM to track real-time glycemic responses during dose escalation.

Preclinical basis: Phase 2 RCT published Diabetes Care 2024; Phase 3 DREAMS-3 head-to-head vs. semaglutide showing superior dual endpoint achievement.

Metabolic Optimization / Thermogenesis

Anecdotal: Emerging

Unlike GIP-dominant tirzepatide, the GCGR pathway drives greater thermogenic activity. Biohackers with interest in cold exposure, mitochondrial uncoupling, and visceral fat reduction are tracking this as a differentiating advantage.

Preclinical basis: Glucagon receptor activation increases energy expenditure in preclinical and Phase 1 pharmacodynamic data; Mazdutide reduces waist circumference significantly beyond placebo in all Phase 3 cohorts.

Scientific References

1.
Bhattachar et al. (2025). Mazdutide reduces body weight in adults with overweight or obesity: A high-dose Phase 1 trial
Diabetes, Obesity and Metabolism2025
High-dose Phase 1 trial demonstrating -20 to -21% body weight reduction with mazdutide up to 16 mg over 20 weeks in non-diabetic adults with obesity.
2.
Innovent Biologics (2025). DREAMS-3 Phase 3 head-to-head trial press release
PR Newswire2025
DREAMS-3 shows mazdutide superior to semaglutide on combined HbA1c + weight loss endpoint in Chinese T2DM adults with obesity.

Safety Profile

Common Side Effects

Nausea (most common, especially during dose escalation; usually transient)
Vomiting
Diarrhea
Constipation
Decreased appetite (can be profound at higher doses)
Injection site reactions (mild, self-limiting)
Fatigue during early dose escalation
Headache
Hypoglycemia risk if combined with insulin or sulfonylureas

Contraindications

Personal or family history of medullary thyroid carcinoma (MTC)
Multiple endocrine neoplasia syndrome type 2 (MEN2)
Pregnancy and breastfeeding (data insufficient)
Severe gastroparesis or gastrointestinal motility disorders
Pancreatitis history (use with caution, monitor)
Severe hepatic or renal impairment (limited data)

Pre-Use Screening Checklist

Thyroid historyDo NOT use

GLP-1 receptor agonists carry a class warning for medullary thyroid carcinoma based on rodent studies. Personal or family history of MTC is an absolute contraindication.

Pancreatitis historyUse with caution

GLP-1 agonists are associated with increased pancreatitis risk. Baseline amylase/lipase and prior history should be assessed.

Gastrointestinal motility disordersVerify before use

Gastric emptying slowing can worsen diabetic gastroparesis or other GI motility conditions.

Cardiovascular diseaseVerify before use

Clinical trials enrolled mostly metabolically healthy obese patients. Limited CV outcome data for mazdutide specifically.

Legal & Regulatory Status

FDA

Not approved. Under Phase 3 clinical development. Investigational compound outside China.

WADA

Not explicitly listed, but GLP-1 receptor agonists are under WADA monitoring list for S4 (hormone and metabolic modulators) category as of 2024-2025.

MEXICO

Not approved by COFEPRIS. Available as research peptide only.

EU

Not approved by EMA. No active marketing authorization application as of 2025.

AUSTRALIA

Not approved by TGA. No registered therapeutic goods listing.

Research Protocols

Dosing protocols based on available research data

Dosing Protocols

Standard weight management (Phase 3 approved escalation)

Subcutaneous (abdomen, thigh, or upper arm)

Dose

2.5 → 5 → 7.5 → 10 mg (weekly steps every 4 weeks)mg

Frequency

Once weekly subcutaneous injection

Duration

—

Route

Subcutaneous (abdomen, thigh, or upper arm)

Note: Standard escalation from Phase 1b 10 mg cohort: 2.5 mg weeks 1-4, 5 mg weeks 5-8, 7.5 mg weeks 9-12, 10 mg maintenance. Inject same day each week. Rotate sites. GI side effects most prominent at each step-up; subside within 1-2 weeks.

Conservative start / GI sensitive individuals

Subcutaneous

Dose

3 mg escalating to 6 mgmg

Frequency

Once weekly, 4-week intervals between step-ups

Duration

—

Route

Subcutaneous

Note: Lower-dose GLORY-1 arm: 4 mg maintenance showed -10% weight at 48 weeks with excellent tolerability. Consider for individuals who struggled with semaglutide GI side effects.

High-dose research protocol (Phase 1, not community standard)

Subcutaneous

Dose

Up to 15-16 mg weeklymg

Frequency

Once weekly with 2-3 week step intervals

Duration

—

Route

Subcutaneous

Note: Phase 1 high-dose study achieved -20 to -21% body weight at 20 weeks. Not a community standard. Only for well-monitored research contexts with medical oversight.

Routes of Administration

Subcutaneous injection

Most common

Standard route used in all clinical trials. Injected into abdominal fat, thigh, or upper arm using an insulin syringe or auto-injector pen.

Rotate injection sites weekly. Inject at consistent day/time. No dose adjustment needed for site selection.

Reconstitution Guide

Solvent / Vehicle

Bacteriostatic water (0.9% benzyl alcohol) for lyophilized powder; pre-filled solutions require no reconstitution

Process

If lyophilized: inject solvent slowly down the vial wall, gently swirl (do not shake), wait until fully dissolved. If pre-filled pen: follow device instructions.

Concentration

For a 10 mg vial: add 2 mL bacteriostatic water = 5 mg/mL. Each 0.1 mL = 0.5 mg.

Storage (Reconstituted)

Refrigerate at 2-8C, use within 28 days.

Storage (Lyophilized)

Store at -20C, protect from light and moisture. Stable at room temperature short-term only.

Timing Notes

Inject on the same day each week. No specific timing requirement relative to meals. Allow 4 weeks at each dose level before escalating.

Pharmacokinetics

Half-Life	Extended half-life of approximately 6.1 to 28.1 days (dose-dependent) due to fatty-acyl modification, supporting once-weekly dosing.
Absorption	Slow subcutaneous absorption; median time to peak plasma concentration (Tmax) approximately 72 hours after injection.
Distribution	Distributed systemically following subcutaneous absorption. Crosses blood-brain barrier to a degree consistent with GLP-1R agonists (hypothalamic appetite centers).
Metabolism	Metabolized via peptide bond hydrolysis and fatty acid chain oxidation. Cleared renally and hepatically.
Molecular Structure	Fatty-acyl modified oxyntomodulin analogue peptide. Proprietary sequence not publicly disclosed. Approximately 30-50 amino acids with C18/C20 fatty acid side chain for albumin binding and extended half-life.

Monitoring & Risk Management

Monitoring guidelines based on available data

Ongoing Monitoring Steps

Body weight and waist circumferenceConfirm progressive weight loss; watch for excessive rapid loss (>1% per week beyond early stages).Check: Monthly
Blood glucose / HbA1cMonitor for hypoglycemia if co-administered with insulin or secretagogues. Track HbA1c trajectory.Check: Every 8-12 weeks
GI symptom severityPersistent vomiting or inability to tolerate oral intake warrants dose pause or reduction.Check: Weekly during escalation
Amylase and lipase (pancreatitis markers)Elevations 3x upper limit of normal or severe epigastric pain radiating to back warrants immediate discontinuation.Check: Every 3 months or if abdominal pain occurs

Critical Warning Signs

Severe abdominal pain radiating to the back, with or without vomitingDiscontinue mazdutide immediately. Seek emergency care. Rule out pancreatitis.Urgency: IMMEDIATE
Neck lump, difficulty swallowing, hoarseness (thyroid nodule symptoms)Discontinue and consult endocrinologist for thyroid evaluation including ultrasound and calcitonin level.Urgency: Within 24-48 hours
Severe persistent nausea and vomiting preventing hydration for 24+ hoursHold dose escalation, reduce to previous tolerated dose, consider antiemetics. IV hydration if unable to maintain oral intake.Urgency: Within 24-48 hours
Symptomatic hypoglycemia (shakiness, sweating, confusion)Treat hypoglycemia with fast-acting carbohydrates. Review concurrent insulin or secretagogue use. Reduce co-medications if confirmed hypoglycemia.Urgency: IMMEDIATE

Health & Research Goals

Mazdutide (IBI362 / LY3305677)