Mazdutide and retatrutide share a company and a first step. Both carry Eli Lilly compound codes (LY3305677 and LY3437943); Innovent Biologics developed mazdutide with Lilly through trials in China, where it was approved in 2025, while Lilly has finished its own phase 3 obesity trials of retatrutide. Both phase 3 programmes start at 2 mg once weekly and climb in four-week steps. Where they part is the number of receptors, the top dose and the regulatory status. This page sets the two dose records side by side (read 2026-10-04) and does the syringe arithmetic. It compares; it recommends neither.
The single-compound records are on the mazdutide and retatrutide dosage pages; the other glucagon-GLP-1 pairing is on survodutide vs retatrutide.
The two dose records
| Mazdutide | Retatrutide | |
|---|---|---|
| Code names | LY3305677, IBI362 | LY3437943 |
| Receptors | Glucagon + GLP-1 | GIP + GLP-1 + glucagon |
| First step | 2 mg weekly | 2 mg weekly |
| Step interval | 4 weeks | 4 weeks |
| Phase 3 doses | 4 mg, 6 mg (GLORY-1); 9 mg (GLORY-2) | 4 mg, 9 mg, 12 mg |
| Highest dose published | 16 mg (phase 1 escalation) | 12 mg |
| Trial population | Chinese adults only | Multinational |
| Approval | China, 2025 | None; filing planned Q1 2027 |
GLORY-1's ClinicalTrials.gov record (NCT05607680) gives the mazdutide steps: the 4 mg arm took 2 mg for four weeks, then 4 mg; the 6 mg arm took 2 mg, then 4 mg, then 6 mg from week 9. Lilly's 2026 releases describe the same pattern for retatrutide, continuing through 6 and 9 mg to reach 12 mg. On paper the first two steps of each ladder are identical — 2 mg for four weeks, then 4 mg — and the ladders separate only above that.
Identical milligrams are still not identical doses. The molecules act on different receptor sets, and mazdutide's 4 mg is its middle phase 3 dose while retatrutide's 4 mg is its lowest.
What each trial reported at each dose
| Trial and dose | Weight change | Placebo | Duration |
|---|---|---|---|
| GLORY-1, mazdutide 4 mg | −11.00% | +0.30% | 48 weeks |
| GLORY-1, mazdutide 6 mg | −14.01% | +0.30% | 48 weeks |
| GLORY-2, mazdutide 9 mg | −16.65% | −1.50% | 60 weeks |
| Retatrutide phase 2, 12 mg | −24.2% | −2.1% | 48 weeks |
| TRIUMPH-1, retatrutide 4 mg | −19.0% | −2.2% | 80 weeks |
| TRIUMPH-1, retatrutide 9 mg | −25.9% | −2.2% | 80 weeks |
| TRIUMPH-1, retatrutide 12 mg | −28.3% | −2.2% | 80 weeks |
GLORY-1 is from the NEJM abstract (PMID 40421736); GLORY-2 (JAMA 2026, PMID 42251595) and the phase 1 16 mg figure are as recorded on this site's mazdutide page; retatrutide phase 2 is from the NEJM abstract (PMID 37366315) and TRIUMPH-1 from Lilly's release of 2026-05-21. The 48-week rows are the only like-for-like duration in the table: mazdutide 6 mg at −14.01% and retatrutide 12 mg at −24.2%, in different populations and different trials.
Population is the first confound. GLORY-1 enrolled Chinese adults with a mean weight of 87.2 kg and a mean BMI of 31.1; the TRIUMPH trials enrolled people with obesity across many countries. Its placebo arm also gained weight (+0.30%) where TRIUMPH-1's lost 2.2%. Discontinuation for adverse events in GLORY-1 was 1.5% (4 mg) and 0.5% (6 mg) against 1.0% on placebo; in TRIUMPH-1, Lilly reports 4.1% (4 mg), 6.9% (9 mg) and 11.3% (12 mg) against 4.9%.
The doses in units, research vials
Neither molecule's research-vial form is covered by a label. Units on a U-100 syringe = mg ÷ mg/mL × 100:
| Dose | 5 mg/mL | 10 mg/mL | 15 mg/mL |
|---|---|---|---|
| 2 mg (either, first step) | 40 units | 20 units | 13.3 units |
| 4 mg (either) | 80 units | 40 units | 26.7 units |
| Mazdutide 6 mg | 120 units ✕ | 60 units | 40 units |
| Mazdutide or retatrutide 9 mg | 180 units ✕ | 90 units | 60 units |
| Retatrutide 12 mg | 240 units ✕ | 120 units ✕ | 80 units |
✕ = more than one 1 mL syringe holds. 15 mg/mL is a 15 mg vial with 1 mL. Above 4 mg the two molecules need different vial arithmetic: a 10 mg vial covers two and a half weeks at mazdutide's 4 mg but cannot supply a single 12 mg retatrutide amount. The mg to units page sets out the formula; the calculator's mazdutide and retatrutide settings handle any vial and volume.
What is not established
No trial compares mazdutide with retatrutide. Mazdutide's dose record is entirely from Chinese adults, and no regulator outside China has reviewed it; the Chinese label itself was not opened for this site. TRIUMPH-1 is known from Lilly's release, not a peer-reviewed paper. No mazdutide half-life figure appears in the abstracts read; retatrutide's is about six days (PMID 39724554). Research-market vials sold under either name have no data of their own. The one registered study that runs mazdutide beside tirzepatide is described on the mazdutide–tirzepatide comparison. The compounds are covered in Medibact's mazdutide guide and retatrutide guide. Nothing on this page is an instruction; dose and product belong with a clinician.
Sources and dates
Opened 2026-10-04: PubMed abstracts 40421736 (Ji et al., NEJM 2025), 37366315 (Jastreboff et al., NEJM 2023) and 39724554 (Tetelbaun et al., Cardiology in Review); ClinicalTrials.gov intervention search for mazdutide AND retatrutide (zero records) and record NCT06143956; PubChem CID 167312357 and a name search for retatrutide (no record). GLORY-1's step schedule (NCT05607680), GLORY-2, the phase 1 16 mg study and the approval dates are as recorded on this site's mazdutide page (2026-09-28); the TRIUMPH figures and Lilly's filing plan as recorded on its retatrutide page from Lilly's releases of 2026-05-21 and 2026-07-23. Unit figures are arithmetic by this site. Corrections go to the contact page.