Tirzepatide
Properties
| Substance class | A synthetic peptide that activates two receptors: the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor. FDA's approved label describes the structure directly - tirzepatide "is based on the GIP sequence and contains aminoisobutyric acid (Aib) in positions 2 and 13, a C-terminal amide, and Lys residue at position 20 that is attached to 1,20-eicosanedioic acid via a linker". That last feature, a 20-carbon diacid on a linker, is the acylation that underlies its long circulating persistence. | source |
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| Mechanism | Described by FDA in its own announcement as acting "by activating receptors of hormones secreted from the intestine (glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)) to reduce appetite and food intake". A peer-reviewed population pharmacokinetic analysis calls it a "first-in-class glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist". This entry records how the mechanism is described in cited work; it is not a claim about any particular material. | source |
| Approval status | APPROVED, and this is the fact that separates tirzepatide from every other compound documented on this network. FDA's substance record lists tirzepatide as an INN, a USAN and a JAN, with a WHO Drug Dictionary entry, and names both marketed brands, Mounjaro and Zepbound. Its development code was LY-3298176. Read what that does and does not mean: an approval attaches to a specific product made to a specific specification by its marketing authorisation holder. It does not attach to a substance by name, and it does not travel to material sold under the same name outside that product. | source |
| Approval for obstructive sleep apnea | On December 20, 2024 FDA approved Zepbound for moderate to severe obstructive sleep apnea in adults with obesity, describing it as "the first drug treatment option for certain patients with obstructive sleep apnea". The approval is for use "in combination with a reduced-calorie diet and increased physical activity". Recorded as a regulatory fact about a named product on a named date. | source |
| Shortage history | Tirzepatide injection had been in shortage since 2022 on increased demand. FDA determined the shortage resolved and states that it "confirmed with the drug's manufacturer that their stated product availability and manufacturing capacity can meet the present and projected national demand". The determination was first made 2024-10-02 and then remanded for reevaluation on 2024-10-22 in the course of litigation, before FDA announced the position again on 2024-12-19. | source |
| Compounding enforcement dates | The dates that closed the lawful compounded-tirzepatide lane. Following the 2024-12-19 announcement, FDA stated it did not intend to take action over violations arising from conditions that depend on the drug's inclusion on the shortage list until 2025-02-18 for a state-licensed pharmacy or physician compounding under section 503A, and until 2025-03-19 for outsourcing facilities under section 503B. FDA adds that it "may still take action regarding violations of any other statutory or regulatory requirements, such as to address findings that a product may be of substandard quality or otherwise unsafe". | source |
| Fda 503b bulks list status | Proposed for exclusion. On 2026-04-30 FDA announced a proposal to exclude semaglutide, tirzepatide and liraglutide from the 503B bulks list, having concluded there is no clinical need for outsourcing facilities to compound them from bulk substances. FDA states that "a determination of clinical need is based on patient safety and medical necessity under the law", and the Commissioner is quoted: "When FDA-approved drugs are available, outsourcing facilities cannot lawfully compound using bulk drug substances unless there is a clear clinical need." | source |
| Half life | ~5 days | source |
| Pharmacokinetics provenance | The half-life figure comes from a population pharmacokinetic model built from 19 pooled studies, which reports that "The half-life of tirzepatide was ~5 days and enabled sustained exposure with once-weekly subcutaneous dosing", and that a two-compartment model with first order absorption and elimination described the data well. Both authors are employees and shareholders of Eli Lilly and Company, disclosed in the paper. That does not make the figure wrong; it is the provenance a reader should have. The measurement describes the approved product in supervised studies. | source |
| Molecular formula | C225H348N48O68 | source |
| Molecular weight | 4813.53 Da | source |
| Molecular data independent cross check | Unusually for this network, the molecular data has two independent sources that agree. FDA's approved label states "The molecular weight is 4813.53 Da and the empirical formula is C225H348N48O68". PubChem's record for CID 166567236 independently gives the same formula and a molecular weight of 4813. The CAS number matches across FDA's substance record and PubChem. On most compounds in this repo the molecular data rests on a single registry entry. | source |
| Cas number | 2023788-19-2 | source |
| Unii | OYN3CCI6QE | source |
| Other names | FDA's substance record gives the preferred name TIRZEPATIDE and records it as an INN, a USAN and a JAN with a WHO Drug Dictionary entry, listing the brand names Mounjaro and Zepbound and the development code LY-3298176. PubChem's synonym list for the same structure adds the CAS number and both trade names. An assigned nonproprietary name records that naming bodies have named the molecule; here, unlike elsewhere in this repo, it sits alongside an actual marketing authorisation. | source |
| Duplicate registry records | A conflation trap worth knowing. A PubChem query by the name "tirzepatide" returns CID 166567236, but a second record, CID 168009818, carries the identical empirical formula C225H348N48O68. Two records with one formula means a figure quoted from "the PubChem entry" does not identify which entry it came from. Look the compound up by CAS or by structure, and check the CID against FDA's substance record, rather than trusting a name lookup. | source |
| Appearance of the approved product | READ THE SUBJECT OF THIS SENTENCE. FDA's approved label describes ZEPBOUND as "a clear, colorless to slightly yellow, sterile solution for subcutaneous use". That is a description of a finished, marketed solution manufactured to a filed specification - not of lyophilised powder, and not of anything sold as research material. No published characterisation of the appearance of non-pharmaceutical tirzepatide supply was located during data entry. | source |
| Excipients of the approved product | The approved solution is not the peptide alone. FDA's label lists, for each single-dose pen or vial, sodium chloride (4.1 mg), sodium phosphate dibasic heptahydrate (0.7 mg) and water for injection alongside the tirzepatide. Recorded because "tirzepatide" as a marketed product and "tirzepatide" as a bulk substance are not the same material, and the formulation is part of what the approval covers. | source |
| Storage | STORAGE FOR THE APPROVED PRODUCT, WHICH IS A SOLUTION. FDA's label directs: "Do not freeze ZEPBOUND. Do not use ZEPBOUND if frozen. Protect ZEPBOUND from heat and light. Store ZEPBOUND in the original carton to protect from light." Single-dose pens and vials are stored refrigerated at 2°C to 8°C (36°F to 46°F), and "If needed, each single-dose pen or single-dose vial can be stored unrefrigerated at temperatures not to exceed 30°C (86°F) for up to a total of 21 days", after which the label directs discarding it. These conditions were established for that formulation in that packaging. They are not a stability statement about a lyophilised powder, and no published stability study of non-pharmaceutical tirzepatide supply was located during data entry. | source |
What the research does not show
- The single most important limitation on this page. Every efficacy, safety, pharmacokinetic and stability figure recorded here was generated with the approved product, manufactured to a filed specification by its marketing authorisation holder. None of it is a measurement of material sold under the same name outside that channel. An approval attaches to a product, not to a word. source
- No independent content or purity analysis of non-pharmaceutical tirzepatide supply was located during data entry. For retatrutide such an analysis exists and found label content ranging from about half to nearly double. Nothing equivalent was found for tirzepatide, so the honest position is that the composition of material sold as research tirzepatide is simply unmeasured in the published record, not that it has been measured and found adequate. source
- The published record describes what tirzepatide does when given as an approved medicine under supervision. It does not establish what any unapproved preparation does, and this site makes no such claim.
- The half-life, formula and storage figures describe physical and pharmacological properties. They are not evidence of benefit, and nothing on this site should be read as a recommendation to use this or any substance.
- The lawful route by which a compounding pharmacy could prepare tirzepatide during the shortage has largely closed: enforcement discretion ended 2025-02-18 under section 503A and 2025-03-19 under section 503B, and on 2026-04-30 FDA proposed excluding the substance from the 503B bulks list entirely. Any description of compounded tirzepatide written before those dates may describe a situation that no longer holds. source
Storage and handling
STORAGE FOR THE APPROVED PRODUCT, WHICH IS A SOLUTION. FDA's label directs: "Do not freeze ZEPBOUND. Do not use ZEPBOUND if frozen. Protect ZEPBOUND from heat and light. Store ZEPBOUND in the original carton to protect from light." Single-dose pens and vials are stored refrigerated at 2°C to 8°C (36°F to 46°F), and "If needed, each single-dose pen or single-dose vial can be stored unrefrigerated at temperatures not to exceed 30°C (86°F) for up to a total of 21 days", after which the label directs discarding it. These conditions were established for that formulation in that packaging. They are not a stability statement about a lyophilised powder, and no published stability study of non-pharmaceutical tirzepatide supply was located during data entry. source
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