# TB-500 Dosage in the Research Literature: Routes, Doses, and Half-Life > TB-500 dosage as it appears in research: the doses and routes used in animal and Phase 1 studies of thymosin beta-4, the half-life question, and why community loading protocols have no clinical basis. What was administered, to which species, by which route — reported as research context, never as a recommendation. No dose here is intended for human use. ## TB-500 dosage in the research literature TB-500 dosage in the research literature is reported almost entirely for full-length thymosin beta-4, across a wide range, and always in animals or in a single human Phase 1 protocol — never as a validated regimen for the heptapeptide. This section describes what was administered to which species; it does not recommend a dose for any person, and the compound is not intended for human consumption [16]. Animal studies dosed thymosin beta-4 broadly: roughly `6-12 mg/kg` in cardiac and neurological rodent models; `2`, `12` and `18 mg/kg` intraperitoneally in the embolic-stroke dose-response study, with a modeled optimal dose of `~3.75 mg/kg` [4]; and `150 µg` twice weekly intraperitoneally for six months in the mdx muscular-dystrophy study [11]. Picogram-to-nanogram amounts are bioactive in vitro — about `~10 pg` was active in keratinocyte migration assays [3]. The single human protocol dosed synthetic thymosin beta-4 intravenously at `42`, `140`, `420` and `1260 mg` (single dose, then daily for 14 days) [6]. Non-clinical "loading then maintenance" protocols that circulate in athletic and peptide-research communities are not derived from controlled human trials and have no published clinical validation [16]. The non-monotonic stroke result — benefit at `2` and `12 mg/kg` but not `18 mg/kg` — directly undercuts the assumption that more is better [4]. ## Can TB-500 be taken orally? The research routes studied for thymosin beta-4 are predominantly intraperitoneal, intravenous, and topical or ophthalmic [16]. Oral dosing of the TB-500 peptide is not supported by controlled efficacy data. As a short peptide it would face the same gastrointestinal proteolysis that limits oral delivery of most peptides, and no study below used an oral route. The compound is supplied for laboratory research use and is not intended for human consumption [16]. ## Routes studied, and what they tell you Four routes appear in the literature, and each maps to a different evidence weight. Intraperitoneal injection is the predominant route in rodent efficacy studies — the wound, stroke, and muscle work all used it [3][4][11]. Intravenous administration is the route of the human Phase 1 safety study of full-length Tβ4 and of some cardiac models [6]. Topical and ophthalmic delivery carries the corneal and dermal wound evidence, including the dry-eye randomized trials of `RGN-259` [5]. Subcutaneous and intramuscular routes are common in community research use but do not appear in controlled human efficacy trials [16]. Reconstitution is straightforward in handling terms: the peptide is supplied as a lyophilized powder for research use, reconstituted in bacteriostatic or sterile water and kept refrigerated [16]. As a short acetylated peptide it is more chemically robust than the full-length protein but is still subject to proteolysis and freeze-thaw degradation, and identity and purity of research-grade material are a recurring concern [16]. ## TB-500 half-life and pharmacokinetics [TB-500 half-life and pharmacokinetics](/dosage) are not characterized for the heptapeptide: no validated human pharmacokinetic half-life exists for the TB-500 fragment [16]. The only controlled human PK data are for full-length thymosin beta-4, where the intravenous Phase 1 study found dose-proportional pharmacokinetics with half-life increasing as dose increased [6]. The other body of PK work on TB-500 is analytical, not clinical: anti-doping LC-MS methods characterize TB-500 and its metabolites in equine plasma and urine for detection purposes, not to establish human pharmacokinetics [16]. So the practical answer is that there is no established human half-life for the molecule sold as TB-500 — the proportional-PK finding belongs to the parent protein given intravenously [6]. ## Why the dose numbers do not transfer to people Three features of this literature block a clean jump from research dose to human regimen. The first is species and molecule: the milligram-per-kilogram figures are rodent doses of the `~4963 Da` protein, not human doses of the `~889 Da` fragment, and allometric scaling between the two is not validated for this compound [16]. The second is the non-monotonic dose-response: in the embolic-stroke study, `2` and `12 mg/kg` improved outcomes while `18 mg/kg` did not, so the data themselves show that a higher dose is not reliably a better one [4]. The third is the absence of a human efficacy endpoint for the fragment — without a completed controlled trial, there is no dose at which the seven-mer has been shown to do anything in a person [11]. This is why community "loading then maintenance" schedules are presented here as community practice, not validated dosing: they are not derived from controlled human trials and have no published clinical validation [16]. Reporting them as protocols would imply a level of evidence the record does not contain. ## Handling, stability, and material quality On the chemistry of the material itself, the record is more concrete. TB-500 is supplied as a lyophilized (freeze-dried) powder for research use, reconstituted in bacteriostatic or sterile water and kept refrigerated [16]. As a short acetylated peptide it is more chemically robust than the full-length protein, but it remains subject to proteolysis and freeze-thaw degradation, so repeated thawing and warm storage degrade it [16]. The larger practical caveat is identity and purity. In unregulated supply, peptide identity, purity, and the correct sequence — and critically whether a vial contains the fragment or the full-length protein — are not guaranteed, which also complicates interpreting any anecdotal result [16]. A reader weighing a tissue-repair claim cannot assume the material a claim is based on matches the molecule in the published studies. None of this is dosing guidance; it is the chemistry context the literature attaches to the compound. --- TB-500 Store runs the thymosin beta-4 literature as a single luminous pipeline — the Ac-LKKTETQ fragment traced from actin binding to tissue repair, every full-length-protein substitution flagged in line, the empty human-trial node left lit, and FDA's 503A standing read before anything else; a research repository, not a clinic, a vendor, or a prescription.