TB-500 dosage, as the studies actually administered it.

TB-500 Dosage in the Research Literature

There is no validated human dose of TB-500. What exists is a record of what investigators administered in defined experiments, almost all using the full-length protein. Reading TB-500 dosage in the research literature means reading those experiments — not a human protocol.

Animal studies dosed full-length thymosin beta-4 across a wide range: roughly 6 to 12 mg/kg in cardiac and neurological rodent models, and 2 to 18 mg/kg intraperitoneally in the embolic-stroke dose-response study, which modeled an optimal dose near 3.75 mg/kg ^[4]. The mdx muscular-dystrophy study used 150 µg intraperitoneally twice weekly for six months ^[5]. In vitro, picogram-to-nanogram amounts are bioactive — about 10 pg drove keratinocyte migration ^[3].

Human dosing data is limited to one Phase 1 study of full-length synthetic Tβ4, given intravenously at 42, 140, 420, and 1,260 mg — a single dose, then daily for 14 days ^[6]. One caution the corpus underlines: the '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 ^[5]. The non-monotonic stroke result — where 18 mg/kg underperformed 12 mg/kg — is a direct argument against the assumption that more is better ^[4].

What the human dose record does and does not establish

The single human dosing dataset deserves to be read precisely, because it is often stretched. In a randomized, placebo-controlled Phase 1 study, synthetic full-length thymosin beta-4 was given intravenously to 40 healthy volunteers in four cohorts of ten — a single dose, then daily for 14 days, at 42, 140, 420, or 1,260 mg. It was well tolerated, with only infrequent mild-to-moderate adverse events and no dose-limiting toxicities or serious adverse events ^[6].

What that establishes is short-term intravenous tolerability of the protein in healthy adults, up to 1,260 mg. What it does not establish is efficacy for any indication, anything about the 889 Da fragment, or anything about subcutaneous or intramuscular administration, which is how research-use communities typically handle TB-500 ^[6]. A Phase 1 study is a safety-and-PK exercise by design; reading it as evidence that the compound works, or that a community injection schedule is safe, asks it to carry weight it was never built for.

The corpus is blunt about the protocols that circulate. 'Loading then maintenance' schedules common in athletic and peptide-research communities are not derived from controlled human trials and have no published clinical validation ^[5]. The non-monotonic stroke data is the cleanest counter-evidence to the loading instinct: 12 mg/kg beat 18 mg/kg in rats, so escalating the dose can lose the effect rather than amplify it ^[4]. None of this is a dosing recommendation; it is a description of what the literature contains and what it does not.

Routes studied and reconstitution context

Routes in the literature track the experimental question. Intraperitoneal injection predominates in rodent efficacy studies, because it delivers a controlled systemic dose conveniently in small animals. Intravenous administration appears in the human Phase 1 of full-length Tβ4 and in some cardiac models. Topical and ophthalmic routes appear in corneal and dermal wound work and in dry-eye trials of clinical-grade Tβ4 (RGN-259), a formulation developed specifically for the eye. Subcutaneous and intramuscular routes appear as community research-use routes, not as routes validated in controlled human efficacy trials ^[5]. The route is not interchangeable with the result: a wound-healing finding from topical application says little about what a systemic injection would do.

As supplied for research, TB-500 is a lyophilized (freeze-dried) powder, reconstituted in bacteriostatic or sterile water and kept refrigerated. As a short acetylated peptide it is more chemically robust than the full-length protein, but it is still subject to proteolysis and freeze-thaw degradation ^[5]. The identity and purity of research-grade material is a recurring concern: in an unregulated supply chain, whether a vial actually contains the correct sequence — and whether it is the fragment or mislabeled full-length protein — is not guaranteed, which also complicates interpreting any anecdotal result ^[5].

TB-500 Half-Life and Pharmacokinetics

There is no validated human pharmacokinetic half-life for the TB-500 heptapeptide. That is the precise, honest statement, and it is the most important fact on this page. Community charts that print a specific half-life figure for the fragment are reporting something the published human literature does not contain.

What is documented is adjacent, and the distinction is worth holding. In the intravenous full-length Tβ4 Phase 1 study, half-life increased with dose — the pharmacokinetics were dose-proportional across the 42 to 1,260 mg range ^[6]. That is a real PK result, but it is for the 4,963 Da protein, not the 889 Da fragment, and dose-proportional behavior in the protein does not transfer automatically to the heptapeptide. Separately, anti-doping LC-MS work has characterized TB-500 and its metabolites in equine plasma and urine — but that work exists to detect the substance in a doping context, not to establish human pharmacokinetics ^[5]. So the fragment is well-described analytically (it can be found and measured) and undescribed pharmacokinetically in humans (how long it persists, how it clears) — two different things that are easy to conflate, and frequently are.

How long does it take for TB-500 to work for injury healing?

There is no validated human timeline. In a rat wound model, topical or intraperitoneal thymosin beta-4 raised re-epithelialization by about 42% at four days and about 61% at seven days versus saline ^[3]. Animal timelines do not establish a human dosing schedule, and the fragment's human kinetics are uncharacterized ^[6].