Tirzepatide and gastric emptying in adults with T1D
What this study tests
A Lilly-sponsored phase 1 randomized placebo-controlled single-dose study (first posted 4 September 2026) of how tirzepatide affects stomach emptying in adults with T1D and overweight or obesity. It uses acetaminophen absorption PK to assess gastric emptying, per the registry; it is not a trial demonstrating improved long-term diabetes outcomes.
Editorial review: .
Registry checked: 2026-10-19. Registry’s own update: 2026-09-23.
Most recent recorded citation date: 2026-09-23. Only explicit date metadata is included; an undated citation may be newer. This does not mean every claim was reviewed on that date.
Trial status, labels and access can change between reviews. How we review the evidence · How to read the evidence
Evidence at a glance
- Who can enter the study?
- Adults aged 18–70 with T1D treated with insulin for at least a year, BMI at least 25 kg/m² and stable weight. The registry lists recruiting status (actual start 11 September 2026) and EU CTIS authorisation in Spain. Registered eligibility ↗Enrollment criteria describe who may enter. They do not establish who was analyzed or the denominator for a reported result.
- Reported benefit and results
- No results posted. The registry lists recruiting status (actual start 11 September 2026, updated 23 September 2026, checked 19 October 2026) and plans 18 participants, with estimated completion in December 2026. This pharmacology study cannot establish a general T1D treatment recommendation.Read the result sources and their limitations →
- Important harms
- Read the reported results, safety discussion and original sources. A separate harms summary is not available; this does not establish safety.
- Research access and approval
- Study regions: United States, European Union. A trial listing does not establish product approval or current recruitment at a particular site. Check the study’s current entry requirements.
- What remains uncertain?
- Read the full discussion and original sources for study limitations. Planned endpoints and completion dates are not results.
Research status alone does not establish approval, clinical benefit or local availability.
Primary endpoints
- Pharmacokinetics (PK): Time of Maximum Observed Drug Concentration (Tmax) of Acetaminophen — Predose on Day 1 through 36 hours post dose
- PK: Area Under the Concentration Versus Time Curve from Time Zero to Time t (AUC0-tlast) of Acetaminophen — Predose on Day 1 through 36 hours post dose
- PK: Maximum Observed Drug Concentration (Cmax) of Acetaminophen — Predose on Day 1 through 36 hours post dose
The full picture
What the study asks
A newly registered Lilly phase 1 study of how tirzepatide affects stomach emptying in adults with T1D and overweight or obesity. It uses acetaminophen absorption to assess gastric emptying; it is not a trial demonstrating improved long-term diabetes outcomes.
Who it involves
Adults aged 18–70 with T1D treated with insulin for at least a year, BMI at least 25 kg/m² and stable weight. The registry lists recruiting status (actual start 11 September 2026) and EU CTIS authorisation (2026-527062-72-00) in Spain. This is a summary; the full registry lists additional criteria.1
Design and timing
The registry lists 18 participants (estimated enrollment). Actual start: 2026-09-11. Primary completion: 2026-12 (estimated). Study completion: 2026-12 (estimated). Estimated dates can change and do not mean results are available.1
Evidence and limits
No results posted. Per the registry, estimated enrollment is 18 and estimated study completion is December 2026 (status: recruiting as of the 23 September 2026 registry update). This pharmacology study cannot establish a general T1D treatment recommendation.
Sources
- [1]A Study of Tirzepatide (LY3298176) in Participants With Type 1 Diabetes Mellitus and Overweight or Obesity (NCT07803744) · Trial registry · 2026-09-23 — Protocol and current registry status checked 19 October 2026 (recruiting; actual start 11 September 2026; EU CTIS 2026-527062-72-00 authorised in Spain 18 September 2026).
ClinicalTrials.gov. NCT07803744. Record checked 19 October 2026; last update posted 2026-09-23.