At a glance
Effects
- Body weight reduction: Phase 2 trials in Chinese adults with obesity reported up to ~20% body weight loss at 9 mg over 60 weeks, and up to −11.2 kg in Western patients with T2DM at higher doses in Phase 1b studies [1][7].
- Glycaemic control (HbA1c): Phase 2 trials reported HbA1c reductions of −1.46% to −2.23% across dose ranges in patients with type 2 diabetes, outperforming placebo and comparable to dulaglutide [7].
- Appetite suppression: GLP-1 receptor activation slows gastric emptying and promotes satiety signalling, reducing food intake [2][5].
- Increased energy expenditure: Glucagon receptor activation drives thermogenesis and fat oxidation, adding a metabolic burn component not present in GLP-1-only drugs [5][8].
- Waist circumference and cardiometabolic markers: Phase 2 data demonstrated improvements in waist circumference, BMI, and multiple cardiometabolic risk factors alongside weight loss [1].
- Potential uric acid reduction: Patent filings document an additional use for uric acid (hyperuricaemia) reduction, noted in investigational studies [9].
GLP-1 / Glucagon receptor dual agonist (incretin-class peptide)
~8 days (fatty-acyl modified; once-weekly dosing)
Subcutaneous injection (abdomen), once weekly
Approved in China (Xinermei®, 2025); NOT FDA-approved — Phase 2 in USA
IBI362 (Innovent) / LY3305677 (Eli Lilly)
About Mazdutide
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- Est. delivery
- 3–7 business days · EU tracked
Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.
What it is
Mazdutide (also known as IBI362 or LY3305677) is a once-weekly, subcutaneously injected investigational peptide drug developed by Innovent Biologics and licensed to Eli Lilly [1][2]. It belongs to the emerging class of dual GLP-1/glucagon receptor agonists and is approved in China (as Xinermei®) for obesity and type 2 diabetes, while still in Phase 2 trials in the United States [3][4].
How it works
Mazdutide simultaneously activates two distinct receptor systems: the GLP-1 receptor (GLP-1R), which suppresses appetite and stimulates insulin secretion, and the glucagon receptor (GCGR), which boosts energy expenditure and fat oxidation [1][5]. Unlike single-target GLP-1 agonists such as semaglutide, this dual action means weight loss is driven by both reduced caloric intake and increased caloric burn [2][5]. The molecule has been structurally modified with a fatty-acyl moiety to extend its half-life to approximately 8 days, allowing convenient once-weekly dosing [3][6].
Risks & side effects
Most important: The most important risk class is the potential for pancreatitis and thyroid C-cell tumours, a concern shared across all GLP-1 receptor agonists as a class effect [6][10]. No cases of pancreatitis or thyroid C-cell carcinoma were observed in mazdutide clinical trials to date, but long-term surveillance data remain limited, and anyone with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia Type 2 (MEN2) must not use this drug [6][10].
Common
Serious
- Pancreatitis (class warning for GLP-1 receptor agonists; not observed in mazdutide trials to date but cannot be excluded) [6][10]
- Hypoglycaemia (especially when combined with insulin or sulfonylureas) [7]
- Gallbladder disease / cholelithiasis (class risk associated with rapid weight loss on incretin therapies) [8]
- Heart rate increase (observed with incretin-class drugs; cardiovascular long-term data for mazdutide are still being collected) [8]
Safety & harm reduction
- Fasting blood glucose and HbA1c (especially in patients with diabetes or pre-diabetes) [7]
- Body weight and BMI at each visit [1]
- Liver function tests (long-term hepatic effects under investigation) [2]
- Serum lipase / amylase if abdominal pain occurs (pancreatitis surveillance) [10]
- Thyroid function and neck palpation in patients with thyroid risk factors [6]
- Heart rate and blood pressure (incretin-class cardiovascular signal) [8]
- Renal function in patients with GI side effects causing dehydration [8]
- Insulin and insulin secretagogues (sulfonylureas): additive hypoglycaemia risk — dose reduction of the concomitant agent may be required [7]
- Oral medications with narrow therapeutic index: delayed gastric emptying may alter absorption timing (e.g. warfarin, oral contraceptives) [8]
- Other weight-loss agents or incretin-based therapies: combination not studied; avoid concurrent use [8]
- Mandatory dose escalation: Start at a low dose (e.g. 2.5–3 mg/week) and titrate upward every 4 weeks to the target dose to minimise gastrointestinal side effects [11]
- Administer as a subcutaneous injection into the abdomen once weekly, on the same day each week [6]
- Rotate injection sites to reduce local reactions [6]
- Discontinue and seek medical attention if persistent severe abdominal pain occurs (possible pancreatitis) [10]
- Long-term safety monitoring required: cardiovascular outcomes, hepatic effects, and thyroid surveillance data are still being collected [2][8]
Dosage context
Dosages used in published clinical trials (not a prescription or recommendation): Phase 1b and Phase 2 studies used once-weekly subcutaneous doses ranging from 3 mg to 10 mg, delivered via structured escalation schedules (e.g. 3 mg weeks 1–4 → 6 mg weeks 5–8 → 9 mg weeks 9–12) [11]. A high-dose Phase 1 study tested up to 16 mg weekly and reported tolerability [12]. Phase 2 obesity trials used doses up to 6 mg over 24 weeks; Phase 1b extended to 9–10 mg [1][11]. These are investigational ranges from controlled trials — no approved dosing regimen exists outside China, and self-administration outside a clinical context carries uncharacterised risks.
Sources
- 1.Nature Communications — Phase 2 RCT (obesity, Chinese adults)
- 2.MuseChem — Mazdutide IBI362 overview
- 3.PeptideJournal — GLP-1/Glucagon dual agonist profile
- 4.FindHonestCare — FDA approval timeline & status
- 5.PatchMD — Mazdutide GLP-1 & glucagon receptor overview
- 6.ThePrEPtide — Mazdutide contraindications & half-life
- 7.Diabetes Care (ADA) — Phase 2 RCT, T2DM (PMC)
- 8.WJG Net — Mazdutide safety & side-effect comparison review
- 9.Patsnap Synapse — Therapeutic class analysis
- 10.Frontiers in Endocrinology — Adolescent case report
- 11.PMC / ScienceDirect — Phase 1b, 9 mg & 10 mg safety trial
- 12.Diabetes Obesity & Metabolism (Wiley) — High-dose Phase 1, up to 16 mg
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.