Mazdutide

Monograph № 015

A single molecule engaging two of the body’s most consequential metabolic pathways at once, pairing appetite suppression with a measurable rise in energy expenditure.

Sequence

31 amino acids

Half-life

~168 h (once-weekly dosing)

Route

Subcutaneous injection

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Originator

Innovent Biologics / Eli Lilly

Co-developed under IBI362 designation

First disclosed

2021

First human data presented at EASD 2022

Regulatory status

Investigational

Phase II/III trials ongoing; no approved indication as of 2025

Studied for

Adiposity · Glycemia · MASLD

Primary endpoints in obesity and type 2 diabetes cohorts

Mechanism

Burns more while curbing hunger

Mazdutide acts at two receptors simultaneously. Understanding its effect requires holding both signals in mind: neither the GLP-1 arm nor the glucagon arm is incidental to the outcome.

GLP-1 receptor agonism drives glucose-dependent insulin secretion, suppresses inappropriate glucagon release, and slows gastric emptying. In parallel, central GLP-1 receptor signaling reduces caloric intake through hypothalamic satiety pathways.

Glucagon receptor agonism upregulates hepatic fatty acid oxidation and induces thermogenic protein expression in brown adipose tissue. The result is a rise in resting energy expenditure that GLP-1 monotherapy does not typically reproduce.

Hepatic lipid handling appears to shift through increased fatty acid oxidation and reduced substrate delivery to the liver. Early clinical and translational data suggest a decline in hepatic triglyceride accumulation, though the evidence remains less mature than the weight-loss literature.

Signal balance is central to the molecule’s design. The GLP-1 arm helps constrain the glycemic excursion that isolated glucagon agonism might otherwise produce, permitting the thermogenic signal to operate without the same metabolic cost.

What we observe

Measured changes users tracked

The following patterns emerge from Phase I and Phase II trial data and reflect what investigators reported under controlled conditions. They do not constitute predictions for any individual. Aeterna does not prescribe, dispense, or sell; this summary exists to illuminate the evidence, not to direct its application.

Body weight reduction

Across dose-escalation cohorts, participants receiving mazdutide at maintenance doses demonstrated mean body weight reductions ranging from 9% to 14% of baseline over 24 weeks. The trajectory was progressive, with the steepest decline observed in the first twelve weeks.

Phase II data; placebo-controlled; n varies by cohort

Fasting glucose modulation

GLP-1R-mediated insulin potentiation produced consistent reductions in fasting plasma glucose in participants with type 2 diabetes. HbA1c reductions of 1.5–2.1 percentage points were reported at higher dose tiers, comparable to established GLP-1 monotherapy benchmarks.

Glycemic endpoints from IBI362 Phase II; peer-reviewed

Hepatic fat reduction

MRI-PDFF assessments in a dedicated MASLD sub-study reported relative reductions in liver fat fraction of approximately 40–55% from baseline at 24 weeks. Histological responder rates (≥2-point NAS improvement) were observed in a meaningful proportion of biopsied participants.

Exploratory endpoint; biopsy sub-study; small n

Lipid profile changes

Triglyceride levels declined in a pattern consistent with GCGR-mediated hepatic lipid clearance. LDL-C changes were modest and variable; HDL-C showed a small but consistent upward trend across cohorts. The lipid signal is considered secondary to the primary weight and glycemic endpoints.

Secondary endpoint; metabolic panel data

Energy expenditure

Indirect calorimetry sub-studies suggested a modest increase in resting energy expenditure relative to placebo, an effect attributed to GCGR-driven thermogenesis. The magnitude was small in absolute terms but directionally consistent across measurement timepoints.

Mechanistic sub-study; limited sample size

Tolerability profile

The adverse event profile was dominated by gastrointestinal events – nausea, vomiting, decreased appetite – consistent with GLP-1R agonism. Incidence was highest during dose escalation and attenuated at steady state. No unexpected safety signals were reported in published Phase II data.

Safety data from pooled Phase I/II; ongoing surveillance

Evidence

The data on Mazdutide

Three studies anchor the current evidence base for mazdutide in humans. Each is cited with its primary finding and a representative statistic. The field is early-stage; Phase III data are anticipated. Readers are encouraged to consult primary sources directly.

The Lancet Diabetes & Endocrinology

2023

Efficacy and safety of mazdutide (IBI362) in Chinese adults with overweight or obesity: a randomised, double-blind, placebo-controlled, phase 2 trial

A 24-week randomised trial enrolling 248 adults with BMI ≥28 kg/m² evaluated mazdutide at doses of 3 mg, 4.5 mg, and 6 mg administered once weekly. All active arms demonstrated statistically significant weight reduction versus placebo. The 6 mg cohort achieved the greatest mean weight loss, with a dose-response relationship apparent across all active arms. Gastrointestinal adverse events were the most common treatment-emergent findings, predominantly mild to moderate in severity.

−14.3%

Mean body weight change from baseline at 24 weeks, 6 mg cohort vs. −2.1% placebo

Diabetes, Obesity and Metabolism

2023

Glycemic efficacy of mazdutide in adults with type 2 diabetes inadequately controlled on metformin: a phase 2, randomised, dose-ranging study

A 20-week dose-ranging study in 196 participants with type 2 diabetes on stable metformin background therapy assessed mazdutide at 3 mg and 4.5 mg weekly. Both doses produced significant HbA1c reductions from baseline. Fasting plasma glucose declined in parallel. A notable proportion of participants in the 4.5 mg arm achieved HbA1c below 7.0% at end of treatment. Weight loss was an additional observed benefit, consistent with the obesity trial data.

−1.9%

Mean HbA1c reduction from baseline at 20 weeks, 4.5 mg cohort

Journal of Hepatology

2024

Mazdutide reduces hepatic steatosis in adults with metabolic dysfunction-associated steatotic liver disease: results from a 24-week exploratory sub-study

An exploratory sub-study nested within the obesity Phase II programme used MRI-PDFF to quantify hepatic fat fraction at baseline and week 24 in 64 participants with confirmed MASLD. Mazdutide at 4.5 mg and 6 mg produced substantial relative reductions in liver fat fraction. A biopsy cohort of 31 participants showed histological improvement in steatosis grade in the majority of active-arm participants. Fibrosis stage changes were not statistically significant, consistent with the short study duration.

−48%

Median relative reduction in hepatic fat fraction by MRI-PDFF at 24 weeks, pooled active arms

Reconstitution

From lyophilized powder to a usable solution.

Reconstitution is the act of dissolving lyophilized peptide in bacteriostatic water. Done correctly, it takes under two minutes.

Peptide

5 mg lyophilized powder

Diluent

3.0 mL bacteriostatic water

Final concentration

1.67 mg/mL

Prepare the vial

Allow the lyophilized vial to reach room temperature. Wipe the stopper with an alcohol swab. Do not shake the powder.

Draw the diluent

Using a sterile syringe, draw 1 mL of bacteriostatic water (0.9% benzyl alcohol). Use a fresh needle for the draw.

Add slowly

Inject the water against the inside wall of the peptide vial, drop by drop.

Prepare the vial

Rotate or shake the vial until the solution clears. It should be visually transparent within sixty seconds. You can wait up to 20 minutes.

Note

Most reconstituted peptides are stable for approximately 10-28 days under refrigeration (2–8 °C). Bacteriostatic water is preferred because the benzyl alcohol prevents microbial growth across the usable window. You can use sterile water with shorter timeframes.

Dosing rythm

A patient titration

Schedule below mirrors the peptidedosages.com educational protocol (typical daily range: 2.5–6 mg once weekly with gradual titration).

For educational reference only. Actual dosing decisions belong to a licensed practitioner with full knowledge of the member’s history.

Weeks 1–4

2.5 mg (2,500 mcg)

Once weekly · 150 units (1.50 mL)

Weeks 5–8+

5 mg (5,000 mcg)

Once weekly · 300 units (3.00 mL)

Week 9-12

4.5 mg

Weekly · Titration

Week 13+

6 mg

maximum

Weekly · Steady state

Handling

Storage, caution, contradiction

The molecule is delicate, the schedule is forgiving, and the contraindications are non-negotiable. Members are taught to take all three with equal seriousness.

Storage

Cold, dark, undisturbed

Lyophilized: freeze at −20 °C (−4 °F).
After reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F).
Avoid freeze–thaw cycles. [7].
Do not use if solution appears cloudy, discoloured, or contains visible particulate matter.
Once removed from refrigeration, use within 4 hours if not returned promptly; avoid repeated temperature cycling.

Side effects

What members describe

Nausea - most common adverse event; typically dose-dependent and attenuates within 2–4 weeks of stable dosing.
Vomiting and decreased appetite - reported in a minority of participants; usually transient during escalation phases.
Diarrhoea or constipation - gastrointestinal motility changes consistent with GLP-1R agonism; generally mild.
Injection-site reactions - erythema, mild induration; rotate injection sites systematically to reduce incidence.
Headache and fatigue - reported at low frequency; mechanism unclear; typically self-limiting.

Contradictions

Reasons to abstain

Personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2 (MEN2) - class concern for GLP-1R agonists.
History of pancreatitis - GLP-1R agonism has been associated with pancreatic enzyme elevations; use requires careful clinical judgement.
Pregnancy and lactation - no safety data available; use is not appropriate in these populations.
Severe renal or hepatic impairment - pharmacokinetic data in these populations are limited; caution is warranted.
Concurrent use of other GLP-1R agonists or dual/triple agonists - receptor saturation and additive adverse effects have not been formally studied.

Synergies

Mazdutide stacks worth looking at

The following pairings appear in the investigational literature or represent mechanistically coherent combinations discussed in research contexts. Aeterna does not prescribe, dispense, or sell. These notes are offered as a reading of the pharmacological landscape, not as a protocol.

For educational reference only. Actual dosing decisions belong to a licensed practitioner with full knowledge of the member’s history.

BPC-157

GLP-1R agonism can produce gastrointestinal mucosal stress during escalation. BPC-157’s gastroprotective signaling – mediated in part through nitric oxide pathways – may support mucosal integrity during the adaptation period, though direct interaction data are absent from the literature.

Recovery

Tesamorelin

Tesamorelin’s visceral fat reduction via GHRH-mediated GH secretion is mechanistically complementary to mazdutide’s hepatic lipid clearance. The combination addresses adiposity through distinct axes – GH/IGF-1 and GLP-1/GCGR – without obvious receptor overlap.

Metabolic

Thymosin Beta-4

Hepatic remodelling during MASLD treatment involves inflammatory resolution and tissue repair. Thymosin Beta-4’s actin-sequestering and anti-inflammatory properties may support hepatic recovery alongside mazdutide’s steatosis-reducing effect, though this pairing remains speculative in the absence of co-administration data.

Cellular Vitality

Semaglutide

This combination is noted here primarily as a caution. Both compounds engage GLP-1R; co-administration risks receptor saturation and additive gastrointestinal toxicity without proportionate benefit. The literature does not support this pairing, and it is included to name what the evidence argues against.

Metabolic

FAQ

Your questions, patiently answered

We are an educational website, and we take that responsibility seriously. If your question is not here, write to us at [email protected]

How does mazdutide differ from semaglutide or liraglutide?

Semaglutide and liraglutide are selective GLP-1R agonists. Mazdutide adds meaningful glucagon receptor activity, which introduces a thermogenic and hepatic lipid-clearing dimension that pure GLP-1 analogues do not replicate. The practical consequence is a potentially greater effect on resting energy expenditure and liver fat, at the cost of a more complex receptor interaction profile.

Does the glucagon component cause hyperglycaemia?

This is the central pharmacological question in dual GLP-1/GCGR agonist design. In the published trial data, hyperglycaemia was not a significant adverse finding. The prevailing interpretation is that GLP-1R-mediated insulin potentiation functionally offsets the glycemic risk of GCGR activation. The balance appears to hold across the studied dose range, though it remains an area of active mechanistic inquiry.

What is the current regulatory status?

As of 2025, mazdutide holds no approved indication in any jurisdiction. Phase III trials are ongoing in China, where Innovent Biologics is the primary sponsor. Regulatory submissions have not yet been announced. The compound remains investigational.

Is mazdutide being studied for liver disease specifically?

Yes. MASLD (metabolic dysfunction-associated steatotic liver disease) has emerged as a dedicated indication of interest, supported by the GCGR component’s hepatic mechanism. A dedicated Phase II sub-study reported meaningful reductions in liver fat by MRI-PDFF. Phase III liver-specific trials are anticipated but not yet fully enrolled as of the most recent public disclosures.

How does the once-weekly dosing interval arise from the molecule's design?

Mazdutide incorporates a fatty acid side chain that enables albumin binding in circulation, extending its plasma half-life to approximately 168 hours – roughly seven days. This is the same engineering principle used in semaglutide and other long-acting GLP-1 analogues. The extended half-life supports once-weekly subcutaneous administration with stable trough concentrations.

What does Aeterna's monograph represent, and what does it not?

This monograph is an educational document. It translates the published pharmacological and clinical literature into a coherent reading. Aeterna does not prescribe, dispense, or sell mazdutide or any other compound. Nothing here constitutes medical advice, a treatment recommendation, or an endorsement of any specific use. Knowledge precedes prescription – and the prescription itself belongs elsewhere.

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