Peptide

TB-500

thymosin beta4 derivative (exact formulation dependent)

Evidence TierDWADA PROHIBITED

tuneTypical Dose

Not established

watchEffect Window

Weeks to 3 months for studied wound endpoints

lockCompliance

WADA PROHIBITED

Overview

Clinical Summary

TB-500 is a synthetic peptide fragment related to thymosin beta-4, studied for tissue repair and angiogenesis. It is used for injury recovery claims, but controlled human outcomes data are minimal.

Preclinical studies suggest enhanced wound healing, angiogenesis, and tendon repair, supporting interest in musculoskeletal recovery. Human evidence is minimal, with few controlled trials showing functional improvements. Minority research explores cardiac repair and anti-inflammatory effects in animal models. Safety, dosing, and long-term outcomes are not well characterized, limiting confidence in net benefit.

Actin/cell migration and wound-healing hypotheses. Clinical evidence is formulation- and route-dependent.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • None established for performance or systemic recovery
  • Topical thymosin beta4 wound healing signal in phase 2 venous ulcer trial

Secondary Outcomes

  • Short-term IV safety tolerability in healthy volunteers

Safety

Contraindications and Interactions

Contraindications

  • Pregnancy/lactation (angiogenic mechanism concern)
  • Active or history of cancer (promotes angiogenesis and cell migration)
  • Active systemic infection
  • Severe liver/kidney disease

Side effects

  • Injection-site reactions (redness, swelling, pain)
  • Headache, nausea, flushing (from phase I IV data)
  • Lethargy during loading phases (anecdotal)

Interactions

  • Immunosuppressants (theoretical additive immune modulation)
  • Anticoagulants (theoretical angiogenic interaction with hemostasis)
  • Other injectable peptides (compounded contamination and attribution risk)

Avoid if

  • Active or history of cancer
  • Competitive athletes (WADA S2 prohibited)
  • Unable to ensure aseptic injection technique
  • Chronic self-use without defined trial period

Evidence

Study-level References

tb-500-SRC-001Systematic absence review point

Evidence statement: no human performance RCT evidence found for TB-500 injection protocol in sports/trauma recovery (systematic absence)

Population: Unproven use-cases

Dose protocol: Not established

Key findings: No high-quality efficacy trials identified for intended TB-500 wellness use.

Notes: This is a structured evidence gap, not a positive efficacy finding.

Paper content

No high-quality efficacy trials identified for intended TB-500 wellness use.

tb-500-SRC-002Randomized, double-blind phase 2
Sourceopen_in_new

https://pubmed.ncbi.nlm.nih.gov/20536470/ doi:10.1111/j.1749-6632.2010.05490.x

Population: 73 adults with venous stasis ulcers

Dose protocol: Topical thymosin beta4, 0.03% optimized dose arm

Key findings: Topical Tbeta4 arm showed higher complete healing (~25%) by 3 months in moderate/smaller wounds.

Notes: Route/formulation mismatch with TB-500 injectable claims.

Paper content

Topical Tbeta4 arm showed higher complete healing (~25%) by 3 months in moderate/smaller wounds.

tb-500-SRC-003Randomized, placebo-controlled phase I
Sourceopen_in_new

https://pubmed.ncbi.nlm.nih.gov/20536472/ doi:10.1111/j.1749-6632.2010.05474.x

Population: 40 healthy adults, 4 cohorts of 10

Dose protocol: 42, 140, 420, 1260 mg single and 14-day IV

Key findings: Well tolerated, no serious adverse events, no dose-limiting toxicity.

Notes: Safety data not equivalent to efficacy proof for recovery claims.

Paper content

Well tolerated, no serious adverse events, no dose-limiting toxicity.

tb-500-SRC-004Preclinical pharmacokinetic and in vitro study.
Sourceopen_in_new

Rahaman KA, Muresan AR, Min H, Son J, Han HS, Kang MJ, Kwon OS. Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro. J Chromatogr B Analyt Technol Biomed Life Sci. 2024;1235:124033. doi:10.1016/j.jchromb.2024.124033. PMID:38382158.

Population: Rat model with in vitro human serum and fibroblast assays.

Dose protocol: Preclinical pharmacokinetic study in rats with in vitro human serum assays

Key findings: The metabolite Ac-LKKTE, not the parent TB-500 peptide, showed significant wound healing activity in fibroblast assays. Raises questions about whether commercially available TB-500 delivers the active species.

Notes: Preclinical only. Adds mechanistic nuance but no human efficacy data.

Paper content

This preclinical study developed analytical methods for TB-500 and its metabolites using high-resolution mass spectrometry. The key finding is that wound healing activity may be attributable to a specific metabolite (Ac-LKKTE) rather than the parent TB-500 peptide itself. Ac-LK was the most abundant metabolite in rat urine at early time points, but Ac-LKKTE was the only fragment showing significant wound healing activity in fibroblast assays. This has implications for understanding which molecular species are actually responsible for biological effects attributed to TB-500, and raises questions about whether commercially available TB-500 products deliver the active metabolite in meaningful amounts. No human pharmacokinetic or efficacy data were generated.

tb-500-SRC-005Narrative review of preclinical evidence.
Sourceopen_in_new

Di H, Huang J, Zhang D, Ni F, Zheng R, Geng H. Thymosin beta 4: An emerging therapeutic candidate for kidney diseases. Peptides. 2026;195:171467. doi:10.1016/j.peptides.2026.171467. PMID:41570941.

Population: Preclinical kidney injury models.

Dose protocol: Preclinical review of thymosin beta-4 in kidney disease models

Key findings: Thymosin beta-4 shows cytoprotective, anti-inflammatory, and antifibrotic effects in kidney injury models. Translational challenges including peptide instability remain.

Notes: Expands preclinical landscape for the parent molecule but provides no human kidney or recovery data.

Paper content

This review maps the preclinical evidence for thymosin beta-4 and its metabolite Ac-SDKP in kidney diseases. The peptide shows cytoprotective, anti-inflammatory, and antifibrotic effects across acute and chronic kidney injury models. The authors discuss bidirectional effects on fibrosis that appear to be model-dependent, and they acknowledge translational challenges including peptide instability and the need for comprehensive safety assessments. This review expands the known preclinical therapeutic landscape for thymosin beta-4 beyond wound healing but provides no human kidney disease data. It is relevant to TB-500 because it contextualizes the parent molecule's broader preclinical activity.

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