LTP·01learntopeptide
Healing & repairPeptideEvidence CCurated profile

TB-500

aka Thymosin Beta-4 fragment

A synthetic fragment of Thymosin Beta-4 investigated for actin regulation, cell migration, and tissue repair pathways.

Molecular wt
889.0g/mol
Formula
C38H68N10O14
CAS
885340-08-9
Half-life
4 h
estimated
Tmax
2 h
Route
Subcutaneous injection
PubChem
62707662

Sequence

One-letter7 residues

Ac-LKKTETQ-OH

Three-letter

Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH

Read this before quoting the sequence
IMPORTANT DISTINCTION: TB-500 is NOT thymosin beta-4. TB-500 is a synthetic, N-terminally acetylated 7-residue peptide corresponding to residues 17-23 (LKKTETQ) of thymosin beta-4 — the actin-binding region. Thymosin beta-4 itself is the full 43-residue protein (PubChem CID 45382195, C212H350N56O78S, MW 4963, CAS 77591-33-4). Ho et al. 2012 state plainly that 'the key ingredient of TB-500 is the peptide LKKTETQ with artificial acetylation of the N-terminus'. Efficacy data generated with full-length thymosin beta-4 should not be attributed to TB-500 without qualification.
Source ↗

Mechanism of action

TB-500, a synthetic version of Thymosin Beta-4, works by binding to actin, a protein that forms part of the cell's cytoskeleton. This interaction promotes cell migration and proliferation, essential for tissue repair. It also enhances angiogenesis by upregulating vascular endothelial growth factor (VEGF), facilitating new blood vessel formation. Additionally, TB-500 modulates inflammation by reducing pro-inflammatory cytokines.

What the evidence actually shows

Grade C

There are limited human trials directly investigating TB-500. Most evidence comes from animal studies and anecdotal reports, which suggest potential benefits in tissue repair and inflammation reduction. Human clinical trials are needed to confirm these effects and establish safety profiles.

Regulatory status

Status
Not approved as a medicine in any jurisdiction identified.
Clinical stage
No registered human clinical trials of TB-500 identified.
WADA
Prohibited at all times. WADA Prohibited List section S2.3 (Growth Factors and Growth Factor Modulators) names 'Thymosin-beta4 and its derivatives e.g. TB-500'.
UK
research_compound

In the UK, TB-500 is not approved for medical use and is considered a research compound. It is not licensed for human consumption.

Source ↗

Pharmacokinetics

Half-life
4 h
Tmax
2 h
Absorption
subcutaneous
Elimination
renal
Washout
3 days
Low-confidence pharmacokinetics
These figures are recorded as estimated rather than measured in a published PK study. Treat them as an order of magnitude. Anything downstream of them — accumulation, steady state, washout — inherits that uncertainty.

Dosing — what backs each figure

TB-500 is the N-terminally acetylated 17-23 fragment of thymosin beta-4 (Ac-LKKTETQ), not full-length Tbeta4, and it has no human clinical trial, no approved label and no published human dose. The only sourced dosing is preclinical: 60 mcg/kg/day intraperitoneally for 4 weeks in a rat Achilles tendon repair model.

PreclinicalAnimal studies — not a human dose

  • 60 micrograms/kg/day for 4 weeks postoperatively

    male Sprague-Dawley rat (12 weeks old, ~330 g), Achilles tendon transection and repair model · intraperitoneal · PMID 42542926

  • TB-500 administered to rats for pharmacokinetic and metabolite quantification (dose not stated in the abstract); the authors note that 'the biological effects of TB-500 have not been documented'

    rat · not stated in abstract · PMID 38382158

Animal doses do not convert to human doses by body weight alone. Route matters too — a compound dosed intraperitoneally in mice tells you little about subcutaneous use.

Commonly circulatedNot established by any study
Dose
Research literature commonly cites ~2 to 2.5 mg twice weekly loading then weekly maintenance
Frequency
2-3x weekly
Cycle
4-8 weeks loading, then maintenance· unsourced

Why this isn't evidence
There is no human trial of TB-500 at any dose, and the entire published TB-500 literature is analytical chemistry, doping-control detection and small rodent studies - the flat 2-2.5 mg loading/maintenance schedule and its 4-8 week cycle exist only in vendor and forum protocols.

This figure is shown because it is what circulates and what people search for — not because it is supported. Cycle lengths in particular tend to be convention copied between compounds rather than anything derived from a compound's own pharmacokinetics.

No established human dose
No approved label or completed human trial establishes a dosing regimen for this compound. Anything presented as a standard protocol for it — anywhere — is someone's convention rather than a finding.

Handling and storage

Lyophilized
Refrigerated (2–8 °C), stable ~24 months
Reconstituted
Refrigerated, use within 30 days
→ Reconstitution walkthrough→ Reconstitution calculator

Safety

Commonly reported
  • ·Injection site irritation
  • ·Mild headache
Rarely reported
  • ·Allergic reactions
  • ·Increased risk of bleeding
Contraindications
  • ·Active malignancy (theoretical)
  • ·Not for human therapeutic use — research chemical
Drug interactions
  • ·Anticoagulants: May increase bleeding risk due to enhanced angiogenesis.

Limited human data; injection-site reactions

Reported combinations

Reported as synergistic
  • ·BPC-157
  • ·"Collagen supplements"
Reported as antagonistic
  • ·NSAIDs: May reduce the peptide's anti-inflammatory effects.

Combination claims in this dataset are largely unsourced and should be treated as folk knowledge until a citation appears beside them.

References (4)

Data provenance

Chemistry and citations on this page were checked against primary sources on 2026-08-14. Values that could not be verified were left blank rather than filled with a plausible guess.

Could not verify
storage, reconstitution, halfLife

Research use only
This profile is educational reference material. It is not medical advice, not a prescription, and not an endorsement of self-administration. Compounds discussed here are research chemicals and most are not approved for human therapeutic use.

Related in Healing & repair

BPC-157
A synthetic pentadecapeptide derived from a protein found in gastric juice. Studied for tissue repair, tendon/ligament healing, and gut protection in preclinical models.
BPC-157 Arginate
BPC-157 Arginate is the arginine salt form of Body Protection Compound 157, a synthetic pentadecapeptide derived from a partial sequence of human gastric juice protein. This formulation pairs the BPC-157 peptide with arginine as a counter-ion, which proponents claim provides improved stability and enhanced oral bioavailability compared to the standard acetate salt form. The underlying peptide consists of 15 amino acids and has demonstrated cytoprotective, anti-inflammatory, and tissue-healing properties across numerous preclinical studies. It promotes angiogenesis, modulates nitric oxide pathways, and upregulates growth factor expression. The arginate form is marketed as offering better gastric survival and systemic absorption when taken orally, though direct head-to-head comparative data remains limited.
GV1001
A 16-amino acid peptide derived from the active site of human telomerase reverse transcriptase (hTERT). Originally developed as a cancer immunotherapy vaccine, now investigated for anti-inflammatory and anti-aging properties.