Mazdutide

Mazdutide (IBI362 / LY3305677) is a long-acting synthetic peptide designed to address obesity and metabolic dysfunction through two complementary hormonal pathways. Unlike traditional GLP-1 medications, mazdutide activates both the glucagon-like peptide-1 (GLP-1) receptor and the glucagon receptor. This dual mechanism helps regulate appetite and blood sugar while potentially increasing energy expenditure and improving fat metabolism. Developed by Eli Lilly and Innovent Biologics, mazdutide is modeled after oxyntomodulin, a naturally occurring hormone involved in energy regulation.

Mazdutide has demonstrated substantial weight loss, improvements in cardiometabolic health, and significant reductions in liver fat during human clinical trials. In June 2025, it became the first dual GLP-1/glucagon receptor agonist approved for chronic weight management in China, followed by approval for type 2 diabetes in September 2025. Although it remains investigational in the United States, its ability to influence both calorie intake and metabolic activity makes it an important development in next-generation obesity and metabolic disease research.

Mazdutide activates two complementary hormone receptors to influence how the body consumes, stores, and utilizes energy.

GLP-1 Receptor Activation: Appetite and Blood Sugar Regulation

• Reduces hunger and increases feelings of fullness.
• Slows gastric emptying, particularly during early treatment.
• Enhances glucose-dependent insulin secretion.
• Improves blood sugar regulation and reduces overall calorie consumption.

Glucagon Receptor Activation: Energy and Fat Metabolism

• May increase energy expenditure through metabolic signaling.
• Promotes hepatic fatty acid oxidation and influences liver lipid metabolism.
• May reduce fat accumulation in the liver.
• Influences pathways involved in metabolic flexibility and nutrient utilization.

The Dual-Receptor Advantage: GLP-1 signaling reduces energy intake while glucagon receptor activation may enhance energy utilization. GLP-1 activity also helps counterbalance glucagon's tendency to increase blood glucose. Although this combined mechanism is supported by pharmacological research, the precise contribution of increased energy expenditure to weight loss in humans is still being investigated.

Mazdutide is attracting attention because it targets both appetite regulation and energy metabolism, potentially addressing several interconnected metabolic conditions through a single treatment.

• Obesity: Demonstrated substantial, dose-dependent weight loss in randomized clinical trials.
• Type 2 Diabetes: Improves glycemic regulation and reduces HbA1c.
• Fatty Liver Disease: Produces significant reductions in liver fat, making it a candidate for further research into metabolic liver disorders.
• Cardiometabolic Health: Clinical studies have reported improvements in waist circumference, blood pressure, blood lipids, and serum uric acid.
• Energy Expenditure: Its glucagon receptor activity provides a distinct mechanism that may complement appetite suppression.

Researchers are also evaluating how mazdutide compares with other metabolic therapies, including semaglutide, tirzepatide, and investigational multi-receptor agonists.

Human clinical trials have identified several promising outcomes associated with mazdutide treatment.

• Significant Weight Reduction: In the GLORY-1 Phase 3 trial, participants receiving 6 mg achieved an average 14.8% weight reduction at 48 weeks, compared with 0.5% for placebo.
• Higher-Dose Weight Loss: A U.S. Phase 2 study reported an estimated 18.1% average weight reduction at 32 weeks in the 16 mg treatment group.
• Liver Fat Reduction: In a GLORY-1 subgroup with elevated baseline liver fat, the 6 mg group experienced an average 80.2% relative reduction in liver fat content.
• Improved Blood Sugar Regulation: Studies involving participants with type 2 diabetes demonstrated clinically meaningful reductions in HbA1c.
• Reduced Waist Circumference: GLORY-1 reported an average 11.0 cm reduction with the 6 mg dose.
• Cardiometabolic Improvements: Favorable changes have been observed in blood pressure, lipid profiles, uric acid, and certain liver enzymes.

Research Perspective: These findings represent clinical trial averages rather than guaranteed individual outcomes. Liver fat reduction does not necessarily indicate reversal of liver fibrosis, and improvements in cardiovascular risk markers do not establish a reduction in heart attacks or cardiovascular mortality.

Mazdutide has been studied primarily as a once-weekly subcutaneous injection. Dosages vary depending on the clinical indication, research population, and study design. Gradual dose escalation has been used to improve gastrointestinal tolerability.

Published Clinical Trial Dosing

Administration: Clinical studies have used subcutaneous injections, generally into the abdomen, thigh, or upper arm according to the applicable treatment protocol.

Important Distinction: The 4 mg and 6 mg doses have been evaluated in Phase 3 obesity research and are among the strengths approved in China. Higher 10 mg and 16 mg regimens are investigational and should not be interpreted as established maintenance doses. Community protocols are not interchangeable with clinically evaluated regimens.

Reconstitution: Published efficacy studies do not validate home reconstitution procedures, bacteriostatic-water ratios, syringe-unit conversions, or universal storage periods for research-market powders. Pharmaceutical formulations should be handled according to their official product instructions.

This table describes clinical research rather than recommending individual treatment or self-administration.

Mazdutide has primarily been investigated through continuous weekly administration rather than short-term cycling.

• Shorter Clinical Studies: Early investigations examined treatment periods of approximately 12–24 weeks.
• Intermediate Studies: Phase 2 programs evaluated weight loss, metabolic outcomes, and tolerability over approximately 24–32 weeks.
• Longer-Term Treatment: The GLORY-1 Phase 3 trial evaluated continuous treatment over 48 weeks.
• Experimental Cycling: Intermittent schedules, such as 24 weeks on followed by 4–12 weeks off, have been proposed in nonclinical discussions but have not been validated as superior to continuous treatment.

Research Consideration: Obesity and type 2 diabetes are often chronic conditions. Interrupting metabolic therapy may result in increased appetite, worsening blood glucose control, or weight regain. There is insufficient evidence that scheduled drug holidays prevent receptor tolerance or improve long-term outcomes.

Mazdutide's dual-receptor mechanism has generated interest in combination strategies targeting other metabolic pathways. However, most peptide combinations discussed in experimental communities have not been evaluated in controlled human trials.

Research Perspective: These combinations are mechanistic hypotheses or experimental community discussions, not clinically validated protocols. Mazdutide has demonstrated substantial effects as a standalone therapy, and adding other investigational peptides may introduce risks without proven additional benefits.

Mazdutide's adverse-event profile is primarily gastrointestinal, resembling other medications that activate GLP-1 receptors. Symptoms are generally more common during treatment initiation and dose escalation.

Less Common but Important Concerns: Severe gastrointestinal reactions, gallbladder complications, pancreatitis-like symptoms, kidney injury associated with dehydration, and clinically significant hypoglycemia when combined with insulin or sulfonylureas require attention.

Trial discontinuation rates vary by dose and study population. Higher investigational doses may present additional tolerability challenges, and long-term safety continues to be evaluated.

Mazdutide requires careful consideration in individuals with existing gastrointestinal, metabolic, or cardiovascular conditions.

• Pregnancy and Breastfeeding: Avoid use because adequate reproductive and developmental safety data are unavailable.
• History of Pancreatitis: Requires careful clinical evaluation because the safety profile in these individuals is not fully established.
• Severe Gastrointestinal Disease: Delayed gastric emptying may worsen symptoms in individuals with significant motility disorders.
• Gallbladder Disease: Rapid weight loss and incretin-based therapies may be associated with gallbladder complications.
• Kidney Impairment: Vomiting or diarrhea may increase dehydration-related kidney risks.
• Diabetes Medications: Concurrent insulin or sulfonylurea therapy may increase hypoglycemia risk.
• Cardiovascular Conditions: Blood pressure and resting heart rate should be evaluated during treatment.
• Other GLP-1 Therapies: Concurrent use with semaglutide, tirzepatide, or other incretin-based drugs lacks established safety and efficacy.
• Prior Serious Allergic Reaction: Individuals with known hypersensitivity to mazdutide or formulation ingredients should avoid exposure.

Regulatory Caution: Mazdutide is not FDA-approved in the United States. Its approval in China does not establish approval, manufacturing quality, or safety for products sold through unregulated research-peptide markets. U.S. contraindications and labeling should not be assumed to be identical to those of other GLP-1 medications.

Clinical investigations of mazdutide have monitored body composition, blood glucose, liver health, and cardiovascular risk factors to evaluate both efficacy and safety.

Research Consideration: Monitoring strategies should reflect the individual's medical history, concurrent medications, and study setting. No single biomarker establishes mazdutide's overall safety or effectiveness.