CompletedPhase 1Results posted

A Study of Tirzepatide (LY3298176) in Healthy Lactating Females

A Study to Evaluate Tirzepatide Concentrations in Breastmilk Following Administration of Single Dose of Tirzepatide by Subcutaneous Injection in Healthy Lactating Females

Lead sponsor

Eli Lilly and Company

Asset

Tirzepatide

Subcutaneous · GLP-1 / GIP dual

Listed sites

Recruiting sites

Actual enrollment

Study population

Healthy volunteers

Eligibility highlights

•BMI 18.5-40•Female•Healthy volunteers

Primary endpoint

•AUC of Tirzepatide in Breastmilk From Zero to Infinity (AUC [0-∞])

Registered trial locations

Locations reported to ClinicalTrials.gov for this trial snapshot. Site count is not enrollment count; per-site enrollment is not available from source.

Identifiers

Registered as

NCT IDNCT05978713

Org study ID18614

Secondary IDI8F-MC-GPINEli Lilly and Company

Timeline

Milestones

Study start2023-07-31actual

Study first posted2023-08-07actual

Primary completion2024-03-12actual

Study completion2024-03-12actual

Last update posted2025-04-27actual

Results first posted2025-04-27actual

Assets

Investigational agents

Tirzepatide

Who this study enrolls

Healthy volunteers

Who can enroll

Minimum age18 Years

SexFemale

Healthy volunteersAccepted

Inclusion criteria

•Participants who are overtly healthy females as determined by medical evaluation

•Female participants who delivered normal-term infant (at least 37 weeks gestation) and are at least 6 weeks postpartum at the time of screening

•Body mass index (BMI) between 18.5 and 40.0 kilograms per meter squared (kg/m²), inclusive

•Female participants who has well-established lactation and is breastfeeding her infant. Note: Breastfeeding must be discontinued prior to the administration of tirzepatide on Day 1 and not resumed for the remaining duration of the study until a follow-up visit (or for total of 29 days after tirzepatide dosing for participants who discontinue early).

Exclusion criteria

•Have a history of inadequate lactation (for multiparous females who have previously breastfed)

•Have confirmed type 1 or type 2 diabetes mellitus

•Regularly use known drugs of abuse or show positive findings on drug screen

Endpoints (2)

What's being measured

Protocol endpoints and posted registry outcome measures, grouped into outcome categories. Composite endpoints show their component event types. Standard codes (LOINC, SNOMED CT) are shown where available.

Safety / tolerability / PK

2 endpoints

Primary/registry result

Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve of Tirzepatide in Breastmilk From Zero to Infinity (AUC [0-∞])

Time frame:Predose, 3, 6, 9, 12, 16, 24, 36, 48, 72, 96, 120, 168, 336, 504, 672 hours post-dose

AUC₀-∞

concentration, descriptive

Posted result

Group	Geometric mean · nanogramhours per milliliter (ngh/mL)	95% CI
5 mg Tirzepatide	NA	-

Primary/protocol endpoint

Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve of Tirzepatide in Breastmilk From Zero to Infinity (AUC [0-∞])

Time frame:Predose, 3, 6, 9, 12, 16, 24, 36, 48, 72, 96, 120, 168, 336, 504, 672 hours post-dose

AUC₀-∞

concentration, descriptive

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2

Snapshot dateJuly 6, 2026

Endpoint classificationDelfa endpoint taxonomy v2 (May 13, 2026)

Results tableClinicalTrials.gov results section

Trial facts come from public ClinicalTrials.gov records. Endpoint categories are Delfa's classification of those records, not a ClinicalTrials.gov field. All figures reflect the July 6, 2026 snapshot.