The purpose of this study is to compare the amount of tirzepatide that gets into the blood stream and how long it takes the body to get rid of it, when given as a solution formulation via an autoinjector versus a conventional prefilled syringe. The tolerability of tirzepatide will also be evaluated and information about any adverse effects experienced will be collected.

Screening is required within 28 days prior to the start of the study. For each participant, the total duration of the clinical trial will be about 14 weeks, including screening.

Inclusion Criteria:

• Healthy males or females of nonchildbearing potential as determined by medical history, physical examination, and other screening procedures
• Are between the body mass index (BMI) of 18.0 and 32.0 kilograms per meter squared (kg/m²), inclusive, at screening
• Are agreeable to receiving study treatment by injections under the skin

Exclusion Criteria:

• Have known allergies to tirzepatide or related compounds
• Have a personal or family history of medullary thyroid carcinoma or have multiple endocrine neoplasia syndrome type 2
• Have a history or presence of pancreatitis (history of chronic pancreatitis or idiopathic acute pancreatitis), elevation in serum amylase or lipase or 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 a prior history of malignant disease(s) in the past 5 years prior to screening
• Smoke more than the equivalent of 10 cigarettes per day
• Is a known user of drugs of abuse

All randomized participants.

Up to 72 days

All participants who received at least one dose of study drug.