CompletedPhase 1Results posted

A Study of the Effect of Tirzepatide on How the Body Handles Birth Control Pills in Healthy Female Participants

Effect of Tirzepatide on Oral Contraceptive Pharmacokinetics in Healthy Female Subjects

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•Female•Healthy volunteers

Primary endpoints

•Period 1 and Period 2, Pharmacokinetics (PK)•Period 1 and Period 2, PK

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 IDNCT04172987

Org study ID17103

Secondary IDI8F-MC-GPGREli Lilly and Company

Timeline

Milestones

Study first posted2019-11-21actual

Study start2020-02-26actual

Primary completion2021-02-09actual

Study completion2021-02-09actual

Last update posted2023-03-27actual

Results first posted2023-03-27actual

Assets

Investigational agents

Tirzepatide

Who this study enrolls

Healthy volunteers

Who can enroll

Minimum age18 Years

Maximum age45 Years

SexFemale

Healthy volunteersAccepted

Inclusion criteria

•Overtly healthy females as determined by medical history, physical examination, and other screening procedures

•Have a body mass index (BMI) equal to or above 18.5 kilograms per meter squared (kg/m²), at screening

•Are not intending to start a family within 2 months after the study

Exclusion criteria

•Have known allergies to either tirzepatide or ethinylestradiol or norgestimate or related compounds

•Have a medical condition or medical history that precludes the taking of combined oral contraceptives

•Have a history or presence of pancreatitis (history of chronic pancreatitis or idiopathic acute pancreatitis), elevation in serum amylase or lipase or gastrointestinal (GI) disorder (eg, relevant esophageal reflux or gall bladder disease) or any GI disease which impacts gastric emptying (eg, gastric bypass surgery, pyloric stenosis, with the exception of appendectomy) or could be aggravated by glucagon-like peptide-1 (GLP-1) analogs or dipeptidyl peptidase IV (DPP-IV) inhibitors

•Have used hormonal implants or received hormonal injections in the past 12 months

•Unwilling to comply with smoking restrictions during the study

•Is a known user of drugs of abuse

Endpoints (8)

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

8 endpoints

Primary/registry result

Period 1 and Period 2, Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve (AUC) Within 1 Dosing Interval (AUC[0-tau]) of Ethinylestradiol (EE)

Time frame:Period 1 and Period 2: Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

AUC₀-∞

concentration, descriptive

Posted result

Group	Geometric mean · picogram hour per milliliter (pg*h/mL)	95% CI
OC (0.035 mg EE and 0.25 mg NGM)	966	-
OC (0.035 mg EE and 0.25 mg NGM) + 5 mg Tirzepatide	811	-

Primary/registry result

Period 1 and Period 2, PK: Maximum Concentration (Cmax) of EE

Time frame:Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

Cmax

concentration, descriptive

Posted result

Group	Geometric mean · picogram per milliliter pg/mL	95% CI
OC (0.035 mg EE and 0.25 mg NGM)	119	-
OC (0.035 mg EE and 0.25 mg NGM) + 5 mg Tirzepatide	49.6	-

Primary/registry result

Period 1 and Period 2, PK: Area Under the Concentration Versus Time Curve (AUC) Within 1 Dosing Interval (AUC[0-tau]) of Norelgestromin (NGMN)

Time frame:Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

AUC₀-∞

concentration, descriptive

Posted result

Group	Geometric mean · pg*h/mL	95% CI
OC (0.035 mg EE and 0.25 mg NGM)	19900	-
OC (0.035 mg EE and 0.25 mg NGM) + 5 mg Tirzepatide	14600	-

Primary/registry result

Period 1 and Period 2, PK: Cmax of Norelgestromin (NGMN)

Time frame:Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

Cmax

concentration, descriptive

Posted result

Group	Geometric mean · pg/mL	95% CI
OC (0.035 mg EE and 0.25 mg NGM)	2070	-
OC (0.035 mg EE and 0.25 mg NGM) + 5 mg Tirzepatide	892	-

Primary/protocol endpoint

Period 1 and Period 2, Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve (AUC) Within 1 Dosing Interval (AUC[0-tau]) of Ethinylestradiol (EE)

Time frame:Period 1 and Period 2: Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

AUC₀-∞

concentration, descriptive

Primary/protocol endpoint

Period 1 and Period 2, PK: Maximum Concentration (Cmax) of EE

Time frame:Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

Cmax

concentration, descriptive

Primary/protocol endpoint

Period 1 and Period 2, PK: Area Under the Concentration Versus Time Curve (AUC) Within 1 Dosing Interval (AUC[0-tau]) of Norelgestromin (NGMN)

Time frame:Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

AUC₀-∞

concentration, descriptive

Primary/protocol endpoint

Period 1 and Period 2, PK: Cmax of Norelgestromin (NGMN)

Time frame:Predose, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16, 24, 48 hours postdose

Cmax

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.