Mazdutide
A once-weekly dual GLP-1/glucagon receptor agonist that became the first dual incretin approved for obesity, reaching market in China in 2025.
Mazdutide is an oxyntomodulin-analog dual agonist that activates both the GLP-1 and glucagon receptors with a single molecule, pairing GLP-1-driven appetite suppression with glucagon-driven increases in energy expenditure and hepatic fat oxidation. Discovered by Eli Lilly and licensed to Innovent Biologics for Greater China, it produced roughly 14-15% mean weight loss at 6 mg and ~20% at 9 mg across the GLORY and DREAMS Phase 3 programs and was approved by China's NMPA in 2025 for chronic weight management and type 2 diabetes. It is not FDA- or EMA-approved; only an earlier-stage US program exists.
Class
Synthetic oxyntomodulin-analog peptide (lipidated dual GLP-1/glucagon receptor agonist)
Half-life
~140-170 hours (5-7 days); once-weekly dosing
Routes
Subcutaneous injection
Category
Weight Loss & Metabolic
Researched benefits
What it's studied for
Substantial weight loss
In the GLORY-1 Phase 3 trial, 6 mg weekly produced ~14.4% mean weight loss over 48 weeks versus 0.3% for placebo in Chinese adults with overweight/obesity; the higher 9 mg dose in the GLORY-2 / DREAMS programs reached roughly 15-20%. This places mazdutide in modern-incretin territory, comparable to semaglutide.
Increased resting energy expenditure
The glucagon-receptor arm raises resting energy expenditure by roughly 5-8% above baseline (~100-200 extra kcal/day at rest) — a metabolic-rate contribution that pure GLP-1 agonists like semaglutide lack, which relies mainly on appetite suppression.
Improved hepatic (NAFLD/MASH) markers
Glucagon agonism stimulates hepatic fatty-acid beta-oxidation and reduces triglyceride synthesis, yielding 20-40% reductions in liver fat (MRI-PDFF) with improved ALT/AST in trials — often exceeding what weight loss alone would predict, a promising signal for fatty liver disease.
Glycemic control in type 2 diabetes
In the DREAMS type 2 diabetes program, mazdutide lowered HbA1c by approximately 2.0 percentage points alongside weight reduction. GLP-1 activity stimulates glucose-dependent insulin secretion and offsets glucagon's glucose-raising effect, keeping glycemic control at least as good as GLP-1 monotherapy.
Favorable lipid profile
Glucagon activity is associated with reductions in LDL cholesterol and triglycerides plus enhanced lipolysis in adipose tissue, contributing to broader metabolic-syndrome improvement beyond weight alone.
Mechanism
How it works
Mazdutide is a synthetic analog of oxyntomodulin, the natural L-cell gut hormone that shares its first 29 residues with glucagon and intrinsically activates both the GLP-1 and glucagon receptors. A single mazdutide molecule therefore engages two Gas-coupled receptors at once: the GLP-1 receptor (GLP1R) and the glucagon receptor (GCGR), both of which raise intracellular cAMP. Lipid conjugation (fatty-acid acylation, similar to semaglutide and liraglutide) drives albumin binding and extends the half-life to roughly 5-7 days, enabling once-weekly subcutaneous dosing.
The GLP-1 arm delivers the class-standard effects: glucose-dependent insulin secretion from pancreatic beta cells, suppression of glucagon release from alpha cells, appetite suppression and satiety signaling in the brainstem and hypothalamus, and slowed gastric emptying. The glucagon arm is the differentiating addition — it stimulates hepatic fatty-acid oxidation and lipolysis in adipose tissue, and increases whole-body energy expenditure.
The apparent paradox of adding glucagon (which normally raises blood glucose) to a metabolic drug is resolved by the counterbalancing GLP-1 activity: GLP-1 stimulates insulin and suppresses the glucagon-driven rise in glucose, so net glycemic control is preserved while the glucagon component contributes fat burning. The result is weight loss comparable to GLP-1 monotherapy plus a measurable 5-8% rise in resting energy expenditure and improved hepatic steatosis. Mazdutide has roughly balanced affinity at both receptors, contrasting with retatrutide's graduated GLP-1/GIP/glucagon activity.
Mazdutide differs mechanistically from the GIP-based incretins: tirzepatide is GIP + GLP-1 and retatrutide is GIP + GLP-1 + glucagon (triple), whereas mazdutide pairs GLP-1 with glucagon and no GIP. Careful design of the GLP-1-to-glucagon activity ratio is credited with keeping cardiac effects modest (heart-rate increases of only ~3-5 bpm in trials) despite the glucagon component.
Dosing protocols
Dosing & administration
Dosing reflects protocols reported in research and community literature for educational purposes. It is not medical advice or a recommendation. Most peptides here are not approved for human use.
Reconstitution
At approval mazdutide is expected as a pre-filled multi-dose pen (Innovent product). Compounded lyophilized powder is typically supplied in 5-10 mg vials reconstituted with bacteriostatic water — e.g. a 10 mg vial + 5 mL BAC water yields 2 mg/mL (a 6 mg dose = 3 mL, a substantial subcutaneous volume). Inject water slowly down the vial wall, swirl gently (never shake, which denatures the peptide), and let dissolve 2-3 minutes to a clear solution. Store lyophilized at 2-8C; reconstituted solution keeps ~28 days refrigerated; never freeze and protect from light. At higher doses consider a more concentrated reconstitution (e.g. 4 mg/mL) or splitting into two injection sites to reduce volume.
Beginner / Titration
- Dose
- 1.5 mg escalating to 6 mg (1.5 to 3 to 4.5 to 6 mg)
- Frequency
- Once weekly
- Timing
- Same day each week, any time of day (long half-life smooths effects)
- Duration
- Weeks 1-16 titration
- Route
- Subcutaneous
1.5 mg weeks 1-4, 3 mg weeks 5-8, 4.5 mg weeks 9-12, 6 mg weeks 13-16. Slow titration minimizes GI side effects, which cluster during dose escalation. Rotate injection sites (abdomen, thigh, upper arm) weekly.
Intermediate / Maintenance
- Dose
- 6 mg (most users); 9 mg if greater loss needed and tolerated
- Frequency
- Once weekly
- Timing
- Consistent weekly schedule
- Duration
- Months 4-12; most weight loss occurs in this phase
- Route
- Subcutaneous
Expected trajectory ~10-12% loss by month 6, ~14-15% by month 12 (matching Phase 3 data). Prioritize protein 1.6-2.0 g/kg ideal body weight and resistance training to preserve lean mass.
Advanced / Maximum
- Dose
- 9 mg (maximum studied)
- Frequency
- Once weekly
- Timing
- Consistent weekly schedule
- Duration
- 12+ months for resistant cases, T2D+obesity, or NAFLD focus
- Route
- Subcutaneous
9 mg is the practical ceiling balancing efficacy (~15-20% loss) against greater GI side effects. Used for inadequate response, complex type 2 diabetes, or hepatic-focused (NAFLD) protocols leveraging glucagon's hepatic effects.
Maintenance (after target)
- Dose
- 3-4.5 mg (reduced) or continued 6 mg
- Frequency
- Once weekly
- Timing
- Consistent weekly schedule
- Duration
- Indefinite / chronic
- Route
- Subcutaneous
Weight-loss drugs are chronic therapies; discontinuation typically causes 50-60% regain within 1-2 years. Options include continued full dose (strongest anti-regain data), reduced maintenance, switching agents, or gradual taper with intensive lifestyle support.
- Titrate in ~4-week increments; slow to 6-8 weeks if GI symptoms are significant. Most nausea occurs during escalation phases.
- Doses studied in the clinical program were 3 mg, 4.5 mg, 6 mg and 9 mg weekly under supervision. Dose-response: ~3% loss at 1.5 mg, ~6% at 3 mg, ~9-10% at 4.5 mg, ~12-14% at 6 mg, ~15% at 9 mg.
- Adjust concurrent medications: insulin often needs a 20-40% reduction and sulfonylureas may be discontinued to avoid hypoglycemia; separate levothyroxine and monitor warfarin INR.
- Best paired with lifestyle intervention: adequate protein, hydration (2-3 L/day, more important given raised energy expenditure), resistance training 3x/week, and 150 min/week cardio.
- Discontinue ~1 week before major surgery in some guidelines due to retained gastric contents (incretin effect); coordinate with the surgical team.
- Not a standalone solution and not a cure — it is a chronic weight-management therapy requiring sustained lifestyle change.
Evidence
Research & clinical studies (4)
GLORY-1: Mazdutide for weight reduction in Chinese adults with overweight or obesity
6 mg weekly mazdutide produced ~14.4-14.84% mean weight loss over 48 weeks versus 0.3% for placebo in Chinese adults with overweight/obesity.
GLORY-2 program: higher-dose (9 mg) mazdutide for chronic weight management
The 9 mg dose reached roughly 20.1% mean weight loss, extending efficacy beyond the 6 mg regimen.
DREAMS-1: Mazdutide in adults with obesity
9 mg weekly mazdutide produced ~15% mean weight loss at 48 weeks in Chinese adults with obesity, comparable to semaglutide's Western results.
DREAMS-2: Mazdutide in type 2 diabetes with obesity
Mazdutide reduced HbA1c by approximately 2.0 percentage points alongside meaningful weight reduction, supporting the type 2 diabetes indication.
Combinations
Stacking & blends
Mazdutide + GH-axis support
Preserve lean mass and target visceral/hepatic fat during weight loss
Tesamorelin targets visceral fat synergistically with mazdutide's hepatic effects, while CJC-1295/Ipamorelin support lean-mass retention. Timing is independent (GH agents in the evening, mazdutide any weekly time). Note: this is a community/off-label combination, not clinically validated.
Mazdutide + reproductive-axis support
Maintain testosterone/HPG function during rapid fat loss
Rapid weight loss can lower testosterone in men; gonadorelin, HCG, or enclomiphene help maintain the HPG axis. Off-label adjunct, not part of the approved regimen.
Mazdutide + recovery peptides
Support joint and tissue recovery during increased training
As activity increases alongside mazdutide, BPC-157 and TB-500 are used by the community for joint/tissue support; timing is independent. Not clinically studied with mazdutide.
Safety
Side effects & considerations
Commonly reported effects
Contraindications & cautions
- Personal or family history of medullary thyroid carcinoma (MTC)
- Multiple endocrine neoplasia type 2 (MEN2)
- Known hypersensitivity to mazdutide or components
- Pregnancy and breastfeeding
- Active eating disorders (anorexia nervosa, severe bulimia)
- Type 1 diabetes (not indicated)
- Known glucagonoma or pheochromocytoma
- History of pancreatitis (high caution)
- Severe gastroparesis, bowel obstruction, or inflammatory bowel disease (caution)
- Recent myocardial infarction or unstable angina (delay/avoid)
GI effects are generally mild, cluster during dose escalation, and improve with slow titration and dietary adjustment (avoid high-fat meals, small frequent meals). The glucagon arm raised theoretical concerns about heart rate and hepatic/cardiovascular effects, but Phase 2-3 Chinese trials showed only modest heart-rate increases (~3-5 bpm), no significant blood-pressure changes, and no cardiovascular safety signals. Hypoglycemia risk rises with concurrent insulin or sulfonylureas. Gallbladder disease risk increases during rapid weight loss. Long-term safety data is less mature than for semaglutide or tirzepatide given the newer development.
FAQ
Mazdutide — common questions
What is mazdutide and how is it different from semaglutide?
Mazdutide (IBI362/LY3305677) is a dual GLP-1 and glucagon receptor agonist built on the oxyntomodulin scaffold, discovered by Eli Lilly and licensed to Innovent Biologics for China. Unlike semaglutide, which targets only GLP-1 (appetite suppression and slowed gastric emptying), mazdutide adds glucagon activity that raises resting energy expenditure ~5-8% and promotes hepatic fat oxidation. It achieves similar weight loss (~15%) but with added metabolic-rate and fatty-liver benefits.
How effective is mazdutide for weight loss?
In the GLORY-1 Phase 3 trial, 6 mg weekly produced 14.4% mean weight loss at 48 weeks versus 0.3% placebo in Chinese adults; the 9 mg dose reached roughly 15-20% in the DREAMS/GLORY-2 programs. That is comparable to semaglutide (~15%) though less than tirzepatide (~22%) or retatrutide (~24% Phase 2), with complementary hepatic and energy-expenditure benefits.
Why add glucagon to a weight-loss drug — doesn't glucagon raise blood sugar?
Pure glucagon does raise glucose, but when combined with GLP-1 (which stimulates insulin and suppresses glucagon response) the net glycemic effect is balanced. What glucagon adds is ~5-8% higher resting energy expenditure, increased lipolysis, and hepatic fatty-acid oxidation that significantly improves NAFLD — the same dual activity seen with the natural hormone oxyntomodulin.
Is mazdutide FDA-approved or available in the US?
No. Mazdutide was approved by China's NMPA in 2025 for chronic weight management and type 2 diabetes, but it is not FDA- or EMA-approved. Innovent holds the China license and Eli Lilly retained ex-China rights but has prioritized retatrutide. An earlier-stage US program exists, but no US NDA has cleared.
How does mazdutide compare to retatrutide and tirzepatide?
All three are multi-receptor incretin agonists but with different receptor combinations: tirzepatide is GIP + GLP-1, retatrutide is GIP + GLP-1 + glucagon (triple), and mazdutide is GLP-1 + glucagon (no GIP). Retatrutide shows greater weight loss (~24% Phase 2), but mazdutide reached market first, in China, ahead of survodutide, the other dual GLP-1/glucagon contender.
What are the main side effects of mazdutide?
Mostly gastrointestinal — nausea (40-55% at full dose), vomiting, diarrhea, and decreased appetite — generally mild and concentrated during dose escalation. The glucagon component adds a modest ~3-5 bpm heart-rate increase. Rare but serious risks include pancreatitis, gallbladder disease during rapid weight loss, and the class thyroid MTC signal from rodent studies.
Does mazdutide help with fatty liver disease (NAFLD)?
Mazdutide shows strong NAFLD effects — 20-40% reductions in liver fat (MRI-PDFF) with improved ALT/AST, often exceeding what weight loss alone would predict, because glucagon-receptor activity directly stimulates hepatic fatty-acid oxidation. It is a promising option for patients with concurrent obesity and fatty liver, though availability is currently limited to China.
Will weight loss be maintained after stopping mazdutide?
Like all effective weight-loss drugs, discontinuation typically leads to significant regain (roughly 50-60% of lost weight within 1-2 years). Mazdutide is emerging as a chronic treatment rather than a finite course, similar to medications for hypertension. Long-term options include continued full dose, reduced maintenance dosing, or a gradual taper with intensive lifestyle support.
