Mazdutide and tirzepatide are both two-receptor drugs built around GLP-1, and both carry Eli Lilly's name: tirzepatide is Lilly's own, and mazdutide (LY3305677) was developed by Innovent Biologics with Lilly and launched in China. Their dose ladders look alike, a low first step and four-week climbs, and their molecules weigh almost the same. Where they differ is the second receptor, the regulatory reach and the size of the effect measured so far. This page sets the two records side by side (read 2026-10-07) and does the syringe arithmetic. It compares; it recommends neither.
The single-compound records are on the mazdutide and tirzepatide dosage pages; mazdutide's other comparison is mazdutide vs retatrutide.
The two dose records
| Mazdutide | Tirzepatide | |
|---|---|---|
| Code names | IBI362, LY3305677 | LY3298176 |
| Receptors | Glucagon + GLP-1 | GIP + GLP-1 |
| Molecular weight (PubChem) | 4,476 | 4,813 |
| First step | 2 mg weekly (GLORY-1) | 2.5 mg weekly (label) |
| Step interval | 4 weeks | at least 4 weeks |
| Maintenance doses studied or labelled | 4, 6 mg (GLORY-1); 9 mg (GLORY-2) | 5, 10, 15 mg |
| Highest published dose | 16 mg (phase 1 escalation) | 15 mg (label maximum) |
| Approval | China, 2025 | FDA (Zepbound, Mounjaro) |
Both ladders climb in four-week steps, and both leave the starting dose as a tolerance step rather than a treatment dose. The mazdutide ladder is shorter: two steps to 6 mg in GLORY-1 against up to five to 15 mg on the tirzepatide label.
The results, each against its own placebo
| Trial | Drug and dose | Length | Weight change | Placebo |
|---|---|---|---|---|
| GLORY-1 (610 adults, China) | Mazdutide 4 mg / 6 mg | 48 weeks | −11.00% / −14.01% | +0.30% |
| GLORY-2 (307 adults, BMI ≥30, China) | Mazdutide 9 mg | 60 weeks | −16.65% | −1.50% |
| SURMOUNT-1 (2,539 adults) | Tirzepatide 5 / 10 / 15 mg | 72 weeks | −15.0% / −19.5% / −20.9% | −3.1% |
At the one dose both have near it, the numbers are close: mazdutide 4 mg gave −11.00% at 48 weeks and tirzepatide 5 mg −15.0% at 72 weeks. Trial length, population (GLORY-1 enrolled Chinese adults with a mean weight of 87.2 kg) and placebo response all differ, so the gap is not a measured difference between the drugs.
The nearest thing to a common yardstick is a network meta-analysis, which links trials through their shared placebo arms. The 2026 BMJ Medicine analysis of 58 trials in adults without diabetes estimated −19.28% for tirzepatide and −13.16% for mazdutide against placebo, with overlapping uncertainty for several comparisons and the authors' caution about "limited head-to-head evidence". It also ranked mazdutide first for tolerability, measured as treatment discontinuation, a point the single trials do not show directly.
Mazdutide does have a head-to-head result, against semaglutide rather than tirzepatide: Innovent's DREAMS-3 (349 adults with type 2 diabetes and obesity, 32 weeks) reported −10.29% on mazdutide 6 mg against −6% on semaglutide 1 mg and an HbA1c change of −2.03% against −1.84% (as reported by HCPLive, 2025-10-28).
The one study with both drugs
ClinicalTrials.gov held three records naming both drugs on 2026-10-07, and only one tests them in parallel. NCT07000955, sponsored by Innovent, randomises 98 Chinese adults with moderate to severe obesity to mazdutide escalated from 2 mg to 15 mg weekly over 44 weeks or placebo (both blinded), with tirzepatide 2.5 mg to 15 mg as an open-label arm. It is a tolerability and pharmacokinetic study at the higher mazdutide dose, not a powered efficacy comparison, and its estimated completion is 2027-05-14. The other two records are a post-bariatric-surgery study using GLP-1 drugs in general and Lilly's obesity master protocol, which tests each drug in its own sub-study.
A milligram against a milligram
Unlike most pairs on this site, these two are close enough in size that milligrams compare roughly molecule for molecule: tirzepatide is about 7.5% heavier, so 4 mg of mazdutide is about 0.89 µmol and 4 mg of tirzepatide about 0.83 µmol. That does not make equal milligrams equal doses. The two drugs bind different second receptors with different potencies, and their trials settled on different milligram ladders for that reason.
Each figure as syringe units
| Amount | 5 mg/mL | 10 mg/mL | 15 mg/mL |
|---|---|---|---|
| Mazdutide 2 mg | 40 units | 20 units | 13.3 units |
| Mazdutide 4 mg | 80 units | 40 units | 26.7 units |
| Mazdutide 6 mg | 120 units | 60 units | 40 units |
| Mazdutide 9 mg | 180 units | 90 units | 60 units |
| Tirzepatide 2.5 mg | 50 units | 25 units | 16.7 units |
| Tirzepatide 5 mg | 100 units | 50 units | 33.3 units |
| Tirzepatide 10 mg | 200 units | 100 units | 66.7 units |
| Tirzepatide 15 mg | 300 units | 150 units | 100 units |
The concentrations are the ones a 10 mg vial with 2 mL or 1 mL of water, or a 15 mg vial with 1 mL, would give. At 5 mg/mL everything above 5 mg overflows a 1 mL syringe. Tirzepatide at the label's compounded concentrations is laid out in both directions on tirzepatide units; the arithmetic for any vial and volume is on the mazdutide calculator and the tirzepatide calculator.
What is not established
No result compares the two drugs in one trial, and the one registered study that includes both is unblinded for tirzepatide and unfinished. Mazdutide's phase 3 record is entirely in Chinese adults; no label for it exists outside China, and no source gives a conversion from one drug's milligrams to the other's. The compounds are covered in Medibact's Mazdutide guide and Tirzepatide guide. Nothing on this page is an instruction; product and dose belong with a prescriber.
Sources and dates
Opened 2026-10-07: ClinicalTrials.gov records NCT07000955 and NCT06143956 and the intervention search for both drugs; the BMJ Medicine network meta-analysis (Chen et al. 2026, PMID 42688617, PMC13536023, full text); HCPLive's report on DREAMS-3 (2025-10-28); PubChem records for mazdutide and tirzepatide. Carried from this site's pages, each with its read date: the GLORY-1 and GLORY-2 figures (PMID 40421736, 42251595; mazdutide page, 2026-09-28), the phase 1 16 mg figure (PMID 40832785) and the Zepbound label and SURMOUNT-1 figures (tirzepatide page, 2026-09-18; label version published 2026-09-02). Units and molar arithmetic by this site. Corrections go to the contact page.