Research index
Neutral one-line summaries with a link to each primary source. Null and negative findings are listed alongside positive ones.
- Population pharmacokinetics of the GIP/GLP receptor agonist tirzepatide — The pharmacokinetic reference for this compound. A population model built from 19 pooled studies; the authors report a two-compartment model with first order absorption and elimination described the data, that the half-life was approximately 5 days, and that covariate analysis suggested dose adjustment based on demographics or subpopulations was unnecessary. Both authors are Eli Lilly employees and shareholders. source
- Effects of Renal Impairment on the Pharmacokinetics of the Dual GIP and GLP-1 Receptor Agonist Tirzepatide — A dedicated pharmacokinetic study in renal impairment, recorded here as part of the characterisation programme behind the approved product. Listed for completeness of the PK record rather than for any efficacy finding. source
- Effects of Hepatic Impairment on the Pharmacokinetics of the Dual GIP and GLP-1 Receptor Agonist Tirzepatide — The companion hepatic-impairment pharmacokinetic study. Same basis for inclusion as the renal study above. source
- Tirzepatide Immunogenicity on Pharmacokinetics, Efficacy, and Safety - Analysis of Data From Phase 3 Studies — An immunogenicity analysis pooled across phase 3 studies. Recorded because immunogenicity is one of the grounds FDA has cited when evaluating peptide bulk substances elsewhere in this repo, and because it is a property of a specific manufactured product rather than of a name. 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