# TB-500 research dosing — Doses, routes, and pharmacokinetics in published literature > Published research doses for TB-500 and Thymosin Beta-4 by route and species, with pharmacokinetic context. Research-context only. Not human dosing guidance. Research-context only. Every number on this page comes from a peer-reviewed study or a registered clinical trial. None of it is a human use recommendation. ## The short version This page records what doses appeared in published research — not a schedule for any person to follow. TB-500 has no FDA label, no approved indication, and no human pharmacokinetic study of the seven-amino-acid synthetic [25][26]. The numbers on this page are study designs from cell culture, rodent models, and registered human trials of full-length Tβ4. Animal doses span a wide range: topical 5 μg for corneal and dermal studies [3][4], 150 μg IP every three days for cardiac epicardial mobilisation [7], 3.75 mg/kg IV as the modelled optimal in rat stroke [9]. Human Phase I trials used intravenous full-length Tβ4 up to 1,260 mg with no dose-limiting toxicities [13]. The "2–10 mg/week subcutaneous" range that circulates in vendor and research-chemical spaces is not anchored to any registered clinical trial [26]. None of the numbers here are a recommendation for use in people. ## Research doses by study, not by patient TB-500 is not approved for any human indication by any major regulator [25] [26]. There is no FDA label, no EMA dossier, and no published human pharmacokinetic study on the synthetic seven-amino-acid heptapeptide. Everything on this page is reproduced from peer-reviewed animal work or from registered human trials of full-length recombinant Thymosin Beta-4. The doses are study designs, not dosing schedules for use in people. **Dermal wound healing (rat, mouse).** Malinda 1999 used 5 μg of Tβ4 per wound in 50 μL PBS topically or intraperitoneally on 8 mm full-thickness rat punch wounds [3]. Philp 2003 used 0.1–5 μg per wound topically on db/db diabetic and aged mouse skin [5]. **Corneal repair (mouse).** Sosne 2002 used 5 μg in 5 μL PBS twice daily as topical ocular dosing after alkali burn [4]. **Cardiac repair and epicardial mobilisation (mouse).** Smart 2007 used 150 μg of Tβ4 intraperitoneally every three days for adult mouse epicardial mobilisation [7]. Bock-Marquette 2004 used an intraperitoneal bolus plus a four-week regimen, with companion intracardiac work in cardiomyocyte culture [6]. **Stroke recovery (rat).** Morris 2010 used 3.75 mg/kg intravenously as a single dose 24 hours post-stroke [8]. The 2014 dose-response identified 3.75 mg/kg as the optimum across a 0.5 / 3.75 / 18 / 36 mg/kg single-dose range, with sustained benefit at day 56 [9]. **Ligament repair (rat).** Xu 2013 used 1 μg of Tβ4 in fibrin sealant delivered locally to the transected medial collateral ligament gap [23]. **Human Phase I safety (US).** Ruff 2010 administered intravenous recombinant Tβ4 at single doses of 42, 140, 420, and 1,260 mg in 40 healthy adult volunteers, with a multiple-dose extension. No dose-limiting toxicities, no serious adverse events [13]. **Human Phase I safety (China).** Wang 2021 administered IV recombinant Tβ4 at single doses of 0.05, 0.25, 0.5, 2.0, 5.0, 12.5, and 25.0 μg/kg in 84 healthy adults, with a multiple-dose extension at 0.5–5.0 μg/kg/day for 10 days. Dose-proportional Cmax and AUC, no SAEs, no DLTs [14]. **Ophthalmic Phase II/III (RGN-259).** 0.1% RGN-259 ophthalmic solution dosed twice daily up to six times daily in the dry eye ARISE programme and at six times daily for 28 days in the neurotrophic keratopathy SEER programme [15] [22]. Vendor and underground research-chemical literature commonly reports subcutaneous dosing schedules of 2–10 mg per week for the TB-500 heptapeptide [26]. None of those numbers is derived from a registered clinical trial, none has a peer-reviewed safety basis, and none should be treated as scientifically grounded. ## Pharmacokinetics: what is published, what is not Published pharmacokinetic data exist almost exclusively for full-length recombinant Tβ4 in humans, not for the seven-amino-acid TB-500 fragment. In the US Phase I (Ruff 2010), plasma concentrations of IV recombinant Tβ4 declined biphasically with rapid distribution and terminal exposure measured over hours, with no obvious accumulation [13]. The Chinese Phase I (Wang 2021) confirmed dose-proportional Cmax and AUC across a 0.05–25 μg/kg single-dose range and across a 0.5–5 μg/kg/day × 10-day repeat-dose schedule [14]. For peptide-based therapeutics of this class, systemic-circulation half-life is typically very rapid — frequently 10–30 minutes for the unprotected peptide. For the synthetic seven-amino-acid TB-500 fragment, the only published primary-source pharmacokinetic and detection work is the equine doping-control LC-MS study by Esposito and colleagues in 2012 [16]. That work detected TB-500 in equine plasma at a lower limit of approximately 0.02 ng/mL and in urine at approximately 0.01 ng/mL after intravenous administration in horses, and explicitly noted that the heptapeptide was unstable in plasma. The commonly cited "1.5–3 hour half-life" figure for TB-500 in rodents originates from vendor and aggregated commercial sources, not from a primary peer-reviewed pharmacokinetic study [26]. The figure should be treated as low-confidence. The N-terminal acetyl cap on the TB-500 heptapeptide blocks aminopeptidase cleavage and improves solution stability versus unprotected LKKTETQ. Full-length Tβ4 is highly water-soluble and stable in plasma due to its largely unstructured, hydrophilic sequence. Both molecules are inactivated by gastric proteases, so oral administration is not pharmacologically meaningful — every published preclinical and clinical study uses parenteral routes (intravenous, intraperitoneal, subcutaneous, intracoronary, local) or topical routes (ocular, dermal). ## Routes studied in the published literature Across the rodent, porcine, equine, and human literature, eight routes of administration have been reported: - **Topical (dermal and corneal).** The clinically prioritised route. Malinda 1999 [3], Sosne 2002 [4], Philp 2003 [5], the RGN-259 ophthalmic programme [15] [22]. - **Intraperitoneal.** Standard rodent systemic dosing. Smart 2007 used IP at 150 μg every three days for epicardial mobilisation in mice [7]; Bock-Marquette 2004 combined IP with intracardiac for the seminal cardiac repair work [6]. - **Intravenous.** The route used in every published human Phase I and Phase II trial of full-length Tβ4. Ruff 2010 [13], Wang 2021 [14], RGN-352 [25], and the Morris stroke programme in rats [8] [9]. - **Subcutaneous.** Rodent dermal and equine doping-control work [16]. - **Local injection in fibrin scaffold.** Xu 2013 delivered 1 μg of Tβ4 directly to the rat MCL transection gap [23]. - **Intracoronary retroperfusion.** Used in the negative closed-chest porcine ischaemia–reperfusion study by Wei 2016 [17]. - **AAV-delivered intramyocardial overexpression.** Used in mouse cardiac fibrosis genetic models in the wider Tβ4 literature. - **Exosome-loaded biomaterial hydrogel.** The modern 2025 diabetic-wound delivery format used by Yu 2025 [20]. The published record establishes the parenteral and topical routes as the only pharmacologically meaningful options. No oral preparation of TB-500 or full-length Tβ4 has been demonstrated to survive gastric proteolysis at therapeutic concentrations [26]. ## What the dose numbers do not tell you A research dose is a study design. It records what investigators chose to administer to a particular species through a particular route to measure a particular endpoint. It does not establish a safe range in humans, an effective range in humans, a duration in humans, or an interaction profile in humans. None of those exists for the TB-500 heptapeptide. The five published human safety datasets are for full-length recombinant Tβ4 [13] [14] [15] [22] [25], a different molecule. The vendor-cited "2–10 mg per week subcutaneous" range for TB-500 is not anchored to any registered trial, any published pharmacokinetic study, or any peer-reviewed safety dataset [26]. Research-chemical-grade TB-500 is sold without GMP manufacturing, lot-release testing, endotoxin control, sterility assurance, or potency verification — contamination and purity risks routinely dwarf the peptide's pharmacology in unregulated use. Phase III RGN-259 trials missed prespecified primary endpoints [15] [22] even with full GMP manufacturing of the parent peptide; the gap between vendor copy and the regulator-grade evidence base is wide. This page surveys what has been studied. Nothing on this page is a recommendation, a protocol, or guidance for use in people. --- An independent editorial console for the peer-reviewed record — not a clinic, not a vendor, not medical advice.