TB-500 (Thymosin Beta-4 Fragment) Half-Life & Pharmacokinetics — Research Guide (2026)

Research-use only. This guide summarises published pharmacokinetic (PK) data on TB-500 (Thymosin Beta-4 Fragment) for laboratory research and educational reference. Nothing on this page is medical advice or a recommendation for human use.

TB-500 (Thymosin Beta-4 Fragment) is classified as a Synthetic fragment of the parent protein Thymosin Beta-4 (Tβ4). Its pharmacokinetic profile — serum half-life, time to peak (Tmax), route-of-administration behaviour, clearance pathway and bioavailability — directly shapes how researchers schedule dosing, interpret PD endpoints and design steady-state experiments.

At-a-Glance Pharmacokinetics

| Parameter | TB-500 | | --- | --- | | Classification | Synthetic fragment of the parent protein Thymosin Beta-4 (Tβ4) | | Serum half-life | Serum half-life is reported in the range of 2–3 hours for the active fragment, with the full Tβ4 parent showing slightly longer elimination kinetics. | | Tmax | Tmax of 1–2 hours following subcutaneous or intramuscular administration in published rodent studies. | | Validated routes | Subcutaneous and intramuscular routes dominate the published literature; intravenous routes have been used in tissue-repair animal models. | | Bioavailability | High subcutaneous bioavailability (>80%) in animal PK studies; oral bioavailability is negligible. | | Clearance | Renal clearance of low-molecular-weight degradation products; the actin-bound pool is recycled through normal cytoskeletal turnover. |

Serum Half-Life

Serum half-life is reported in the range of 2–3 hours for the active fragment, with the full Tβ4 parent showing slightly longer elimination kinetics.

Tissue vs Serum

Tissue retention is extended via actin-binding and integration into the G-actin sequestration pool, producing a functional duration of action well beyond serum clearance.

The functional implication is that steady-state PK is reached at approximately 4–5 half-lives. For TB-500, that informs how quickly researchers can expect plasma exposure to stabilise across repeat dosing.

Time to Peak (Tmax)

Tmax of 1–2 hours following subcutaneous or intramuscular administration in published rodent studies.

Tmax is the parameter that most directly governs acute pharmacodynamic readouts. For GH-axis peptides this dictates blood-sampling timing for stimulated GH; for incretin analogues it shapes the post-prandial glucose challenge window.

Routes of Administration

Subcutaneous and intramuscular routes dominate the published literature; intravenous routes have been used in tissue-repair animal models.

Bioavailability across routes: High subcutaneous bioavailability (>80%) in animal PK studies; oral bioavailability is negligible.

Clearance & Metabolism

Renal clearance of low-molecular-weight degradation products; the actin-bound pool is recycled through normal cytoskeletal turnover.

Key Pharmacokinetic Takeaways

• 17–amino-acid fragment of the larger Tβ4 protein; the fragment is the active research entity
• Pharmacokinetic duration is decoupled from serum half-life because of actin binding
• Twice-weekly loading protocols are common in published animal repair models
• Reconstituted vials retain potency for ~14–28 days refrigerated under standard handling

Frequently Asked Questions

What is the half-life of TB-500? Serum half-life is reported in the range of 2–3 hours for the active fragment, with the full Tβ4 parent showing slightly longer elimination kinetics.

How quickly does TB-500 reach peak concentration? Tmax of 1–2 hours following subcutaneous or intramuscular administration in published rodent studies.

Which routes of administration are validated in published research? Subcutaneous and intramuscular routes dominate the published literature; intravenous routes have been used in tissue-repair animal models.

Does TB-500 accumulate with repeat dosing? Renal clearance of low-molecular-weight degradation products; the actin-bound pool is recycled through normal cytoskeletal turnover. Steady-state is typically reached at 4–5 half-lives in published multi-dose studies.

Is oral bioavailability meaningful for TB-500? High subcutaneous bioavailability (>80%) in animal PK studies; oral bioavailability is negligible.

Related Research

• Reconstitution & storage protocols — see the TB-500 reconstitution guide for vial handling that preserves the PK profile described above.
• Dosing protocols research — see the TB-500 dosing protocols article for how PK parameters translate into scheduling decisions.
• Mechanism of action — see the TB-500 mechanism guide for the receptor-level basis of the PD effects driven by the PK profile.

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*Sources cited inline are drawn from published preclinical and clinical pharmacokinetic literature. This article is for laboratory research and educational use only and does not constitute medical advice.*