TB-500 dosage: what was administered, to which species, by which route

TB-500 Dosage in the Research Literature

TB-500 dosage in the research literature is, like the efficacy data, mostly a record of full-length thymosin beta-4 doses, and it spans a wide range by model. In rodent cardiac and neurological studies, doses ran roughly 6 to 12 mg/kg; the embolic-stroke dose-response study tested 2, 12, and 18 mg/kg intraperitoneally, with a modeled optimal near 3.75 mg/kg ^[4]. The mdx muscular-dystrophy study used 150 µg twice weekly intraperitoneally for 6 months.

Human dosing exists only for the parent protein and only intravenously: the Phase 1 study administered 42, 140, 420, and 1260 mg — a single dose, then daily for 14 days ^[6]. At the other extreme, picogram-to-nanogram amounts are bioactive in vitro, with ~10 pg active in keratinocyte-migration assays ^[3]. None of this is a human-use schedule for the TB-500 fragment, and the "loading then maintenance" protocols circulating in athletic communities are not derived from controlled human trials and have no published clinical validation.

TB-500 Half-Life: What the Research Shows

No validated human pharmacokinetic half-life exists for the TB-500 heptapeptide. The only relevant human PK is from the intravenous full-length Tβ4 Phase 1 study, in which pharmacokinetics were dose-proportional and half-life increased with dose ^[6].

Anti-doping LC-MS work has characterized TB-500 and its metabolites in equine plasma and urine, but that is detection chemistry, not a human PK profile. So the honest half-life statement for the fragment is that it has not been measured in humans.

Can TB-500 be taken orally?

The studied routes are intraperitoneal, intravenous, and topical/ophthalmic. As a peptide, TB-500 is subject to gastrointestinal proteolysis, and no oral research dosing is validated. Oral administration is not a route the literature supports for the fragment.

Routes studied

Intraperitoneal injection predominates in rodent efficacy studies ^[3][4]. Intravenous dosing appears in the human Phase 1 of full-length Tβ4 and in some cardiac models ^[6][2]. Topical and ophthalmic routes carry the corneal and dermal wound work and the dry-eye RCTs of Tβ4 / RGN-259 ^[7]. Subcutaneous and intramuscular routes circulate as community research-use routes but are not drawn from controlled human efficacy trials.

Material handling is consistent across the literature: TB-500 is supplied as a lyophilized powder for research use, 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 still degrades with proteolysis and freeze-thaw cycling, and identity and purity of research-grade material are a recurring concern.

Why "more" is not a dosing strategy here

The community "loading then maintenance" pattern assumes a dose-response that the animal data do not support. The clearest counterexample is the rat embolic-stroke study: 2 and 12 mg/kg improved neurological outcomes, but 18 mg/kg did not, and the modeled optimal sat near 3.75 mg/kg ^[4]. Higher was not better; in that model it was worse than the middle of the range.

That non-monotonic shape matters for anyone reading dosing folklore. A protocol built on the premise that escalating the amount escalates the benefit is contradicted by the one dedicated dose-response study in the file ^[4]. It is another reason this page reports doses as study facts rather than as a ladder to climb.

Material quality and why it complicates dosing talk

Even setting aside the human-data gap, a stated "dose" of research-grade TB-500 assumes the vial contains what the label says. Identity, purity, and the correct sequence — full-length protein versus the Ac-LKKTETQ fragment — are a recurring concern in unregulated supply, and that uncertainty also complicates interpreting any anecdotal result.

Handling adds further variability: the peptide is supplied lyophilized, reconstituted in bacteriostatic or sterile water, and degraded by proteolysis and repeated freeze-thaw cycles. Between an unverified starting amount and post-reconstitution degradation, a nominal figure in a forum may not correspond to what was actually delivered — one more reason a number from the literature does not transfer to a person.

Why no human dosing is stated here

There are no completed controlled clinical trials of the TB-500 heptapeptide for any indication. Human clinical data exist only for full-length synthetic thymosin beta-4 — the IV Phase 1 safety study and topical ophthalmic trials ^[6]. Because the fragment has no validated quantitative profile of its own and is not an approved medicine, this page reports what was administered in studies and to which species, and it does not translate any figure into a human protocol. The regulatory side of that boundary is covered in the TB-500 legal status and 503A compounding access file.