Tirzepatide and survodutide are both weekly injected peptides that act on the GLP-1 receptor, but each adds a different second target: tirzepatide the GIP receptor, survodutide the glucagon receptor. Tirzepatide has two US labels and a fixed dose ladder; survodutide has a finished phase 3 obesity trial and no approval. People comparing them want to know which works better and how the doses line up — the first has no trial answer yet, the second does. 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 tirzepatide and survodutide dosage pages; survodutide against the triple agonist is on survodutide vs retatrutide. For the molecules' outcomes in a magazine format, GLP1 Ledger's survodutide vs tirzepatide covers ground this page does not repeat.
The two dose records
| Tirzepatide | Survodutide | |
|---|---|---|
| Developer | Eli Lilly | Boehringer Ingelheim |
| Receptors | GIP + GLP-1 | Glucagon + GLP-1 |
| Status | Approved (Mounjaro, Zepbound) | Not approved |
| First step | 2.5 mg weekly for 4 weeks (label) | 0.3 mg weekly (phase 2) |
| Step size and interval | +2.5 mg, every ≥4 weeks | Two-week steps in phase 2; lengthened in phase 3 |
| Doses | 5, 10, 15 mg maintenance | 3.6, 6.0 mg (phase 3) |
| Half-life | About 5 days (label) | Not stated in the abstracts read |
| Molecular weight | 4,813 | 4,232 |
The tirzepatide ladder is printed on its labels; survodutide's phase 2 ladder was posted week by week on ClinicalTrials.gov (NCT04667377) — 0.3, 0.6, 0.9, 1.2, 1.8, 2.4, 3.3, 4.2 mg to 4.8 mg at week 17. Boehringer's phase 3 design paper lengthened those steps because gastrointestinal events clustered during escalation and allows holding a dose for 2 to 4 weeks, but does not print the table.
Two arithmetic points before any comparison. Survodutide's top phase 3 dose, 6.0 mg, is less than half tirzepatide's 15 mg maximum and sits between tirzepatide's 5 mg and 7.5 mg steps; and by PubChem's molecular weights a milligram of survodutide holds about 1.14 times as many molecules as a milligram of tirzepatide. Neither point says anything about effect, because the molecules act on different second receptors.
What each trial reported at each dose
| Trial and dose | Weight change | Placebo | Duration |
|---|---|---|---|
| SURMOUNT-1, tirzepatide 5 mg | −15.0% | −3.1% | 72 weeks |
| SURMOUNT-1, tirzepatide 10 mg | −19.5% | −3.1% | 72 weeks |
| SURMOUNT-1, tirzepatide 15 mg | −20.9% | −3.1% | 72 weeks |
| Survodutide phase 2, 4.8 mg | −14.9% | −2.8% | 46 weeks |
| SYNCHRONIZE-1, survodutide 3.6 mg | −12.2% | −5.4% | 76 weeks |
| SYNCHRONIZE-1, survodutide 6.0 mg | −13.0% | −5.4% | 76 weeks |
All from the published abstracts (PMID 35658024, 38330987, 42253238). The two phase 3 trials are the closest pair on this site's GLP-1 pages — both in adults without diabetes, both about a year and a half long — and the gap remains confounded. SYNCHRONIZE-1's placebo arm lost 5.4%, against SURMOUNT-1's 3.1%, and the survodutide figures use a treatment-regimen estimand that counts people who stopped. Tolerability is reported in different terms too: discontinuation for adverse events in SURMOUNT-1 was 4.3%, 7.1% and 6.2% on 5, 10 and 15 mg against 2.6% on placebo, while the SYNCHRONIZE-1 abstract gives gastrointestinal events in 80.9% and 89.7% against 47.9%.
The planned switch study
The one registered study naming both drugs is not a comparison. SYNCHRONIZE-START (NCT07855900) is an open-label phase 3b study of 350 adults in two cohorts: people starting survodutide for the first time, and people switching to it from semaglutide or tirzepatide. Its primary outcome is weight change at week 52. The record, updated on 2026-10-02, gives an estimated start of 2026-11-07 and does not state at what tirzepatide dose people switch or at what survodutide dose they begin. Until it reports, no data describe a tirzepatide-to-survodutide switch; the switching pages on this site for approved molecules, such as tirzepatide to semaglutide, rest on labels this pair lacks.
The doses in units, research vials
Neither 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 | 30 mg/mL |
|---|---|---|---|---|
| Survodutide 0.3 mg | 6 units | 3 units | 2 units | 1 unit |
| Survodutide 3.6 mg | 72 units | 36 units | 24 units | 12 units |
| Survodutide 6.0 mg | 120 units ✕ | 60 units | 40 units | 20 units |
| Tirzepatide 2.5 mg | 50 units | 25 units | 16.7 units | 8.3 units |
| Tirzepatide 5 mg | 100 units | 50 units | 33.3 units | 16.7 units |
| Tirzepatide 10 mg | 200 units ✕ | 100 units | 66.7 units | 33.3 units |
| Tirzepatide 15 mg | 300 units ✕ | 150 units ✕ | 100 units | 50 units |
✕ = more than one 1 mL syringe holds. Tirzepatide research vials in this site's data come in 10, 15 and 30 mg, survodutide in 5, 10 and 15 mg, so the 30 mg/mL column applies to tirzepatide only. The labelled products need none of this: a Zepbound single-dose vial holds the whole dose in 0.5 mL. The mg to units page sets out the formula; the calculator's tirzepatide and survodutide settings handle any vial and volume.
What is not established
No completed trial compares survodutide with tirzepatide, and no data describe switching between them. Survodutide has no regulator-reviewed dose, its phase 3 escalation table is unpublished, and no half-life figure was found in the abstracts read. Research-market vials sold under either name have no data of their own. The compounds are covered in Medibact's tirzepatide guide and survodutide guide. Nothing on this page is an instruction; dose and product belong with a clinician.
Sources and dates
Opened 2026-10-04: the Mounjaro label (Eli Lilly, DailyMed set id d2d7da5d-ad07-4228-955f-cf7e355c8cc0, published 2026-09-02), sections 11, 12.1 and 12.3; PubMed abstracts 35658024 (Jastreboff et al., NEJM 2022), 42253238 (le Roux et al., NEJM 2026) and 38330987 (le Roux et al., Lancet Diabetes Endocrinol 2024); ClinicalTrials.gov intervention search for survodutide AND tirzepatide and record NCT07855900; PubChem CIDs 166567236 and 171378821. The tirzepatide escalation schedule is as recorded on this site's tirzepatide pages from the Zepbound label (2026-09-18); the survodutide phase 2 escalation and phase 3 design paper as recorded on its survodutide page (2026-09-26). Unit and molecule arithmetic by this site. Corrections go to the contact page.