Peptide Encyclopedia / Tirzepatide
EncyclopediaTirzepatide is a 39-amino-acid peptide that activates both the GIP and GLP-1 receptors, given as a once-weekly injection. FDA approval covers Mounjaro for type 2 diabetes and Zepbound for chronic weight management and obstructive sleep apnea, backed by the SURPASS and SURMOUNT trials, with a boxed warning for thyroid C-cell tumors. Below you'll find reported dosing, reconstitution, safety, and legal status. Educational only, not medical advice.
| Also known as | Mounjaro, Zepbound, LY3298176 |
| Half-life | 5 days |
| Regulatory status | FDA-approved. |
FDA-approved. Approved as Mounjaro for type 2 diabetes mellitus (initial U.S. approval 2022) and as Zepbound for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity (approved November 8, 2023), and subsequently for moderate-to-severe obstructive sleep apnea in adults with obesity. Manufactured by Eli Lilly. Carries an FDA boxed warning for thyroid C-cell tumors.
Tirzepatide is a 39-amino-acid synthetic peptide that selectively binds to and activates both the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor, the targets for native GIP and GLP-1. It is acylated with a C20 fatty diacid moiety that enables albumin binding to prolong its half-life. It enhances first- and second-phase insulin secretion and reduces glucagon, both in a glucose-dependent manner, while lowering fasting and postprandial glucose, decreasing food intake, and reducing body weight. Pharmacokinetics (half-life Approximately 5 days, supporting once-weekly subcutaneous dosing.): Steady state is reached after approximately 4 weeks of once-weekly administration. Tirzepatide is eliminated by proteolytic cleavage of the peptide backbone and metabolism of the C20 fatty diacid moiety. Its long half-life is attributable to albumin binding conferred by the fatty diacid.
Supported by the Phase 3 SURPASS program (type 2 diabetes) and SURMOUNT program (obesity). In SURPASS-2, tirzepatide (5, 10, 15 mg) was noninferior and superior to semaglutide 1 mg for HbA1c reduction at 40 weeks in patients with type 2 diabetes. In SURMOUNT-1, a 72-week trial in adults with obesity, tirzepatide produced substantial sustained weight reduction (up to ~20.9% at the 15 mg dose) versus placebo. Reported use: Per FDA labeling, the reported regimen is once-weekly subcutaneous injection. Mounjaro is initiated at 2.5 mg once weekly for 4 weeks, then increased to 5 mg, with further increases in 2.5 mg increments after at least 4 weeks as needed up to a maximum of 15 mg once weekly. Zepbound follows a similar titration schedule for weight management. This reflects label-directed clinical use and is not prescriptive guidance.
Boxed warning: tirzepatide causes dose-dependent thyroid C-cell tumors (including medullary thyroid carcinoma) in rats; human relevance is not determined. The most common adverse reactions are gastrointestinal (nausea, diarrhea, vomiting, constipation, abdominal pain). Other labeled risks include acute pancreatitis, gallbladder disease, acute kidney injury (related to volume depletion from GI losses), hypoglycemia when used with insulin or sulfonylureas, diabetic retinopathy complications, and hypersensitivity reactions..
Personal or family history of medullary thyroid carcinoma (MTC), Multiple endocrine neoplasia syndrome type 2 (MEN2), Known serious hypersensitivity to tirzepatide or any excipient.
Insulin secretagogues (e.g., sulfonylureas) or insulin: increased risk of hypoglycemia; dose reduction may be needed, Oral medications: delayed gastric emptying may affect absorption of concomitant oral drugs, Oral hormonal contraceptives: reduced effectiveness possible; non-oral contraception or barrier method advised per label
Log every dose and injection site, get the reconstitution and units math automatically, follow your cycle, and record how you feel, then export a provider report. Tirzepatide tracker, free to start.
PepWise is an informational and educational tracking tool, not medical advice and not a medical device. Tirzepatide may be experimental, restricted, or prescription-only; many research peptides are not FDA-approved. Consult a licensed healthcare provider before starting, changing, or stopping any protocol. Operated by STC Consulting, Inc.
