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PeptideHormone

TB-500

A synthetic thymosin β4 fragment marketed for recovery; preclinical evidence.

Research peptidePreclinicalUnapprovedBased on Thymosin β4Compare with Tβ4 Compare lineage

A synthetic fragment sold under the name of the protein it came from. The parent biology is genuine; the fragment's own human evidence is not yet there.

Identity

Class
N-acetylated thymosin β4 fragment (7 aa; Ac-LKKTETQ)
Source
Synthetic; based on thymosin β4
Receptor
No established receptor; fragment effects cannot be assumed equivalent to thymosin β4

Key properties

Evidence floorCommunityCOMM1
Half-life (native)
Poorly characterized in humans
COMMHalf-life is poorly characterized in humans. The figure is indicative of order-of-magnitude, not an established value.

Approximate values for the native hormone; engineered analogs are often deliberately larger and far longer-acting. Each figure carries its own provenance tier, and the floor is the weakest of them - the Standard.

Mechanism

FDA's 2026 evaluation describes TB-500 as Ac-LKKTETQ, the N-acetylated fragment corresponding to residues 17–23 of thymosin β4. Commercial naming is inconsistent. Findings for the full-length 43-amino-acid peptide or unacetylated LKKTETQ cannot establish the fragment's clinical effects. Human recovery benefits are not established.

Reference notes

  • TB-500 is derived from thymosin β4 but is not identical to the full endogenous peptide.
  • Its claims lean on thymosin β4 biology; direct human evidence for TB-500 is limited.
  • It is a 'research peptide' product — read the evidence honestly.

Regulatory status

United States · reviewed September 2026
UnapprovedTB-500 is sold outside the approved-drug system as research-use-only material, with no FDA approval for human use.
Basis
A synthetic Tβ4 fragment with no drug development history; sold research-use-only. In July 2026 the Pharmacy Compounding Advisory Committee voted 8–6 with one abstention to recommend adding it to the 503A list, against FDA staff advice; the vote is non-binding and the status stands pending rulemaking.

Status describes the molecule as a drug substance under US law and is an editorial reading of the public record — approvals, trial registrations, and the FDA 503A bulk-substances list. It is not legal advice and it changes; the review date above is the last time the table was checked. Other jurisdictions are noted only where they differ materially.

Common questions

What is TB-500?
A synthetic thymosin β4 fragment marketed for recovery; preclinical evidence. Structurally it is N-acetylated thymosin β4 fragment (7 aa; Ac-LKKTETQ).
How does TB-500 work?
FDA's 2026 evaluation describes TB-500 as Ac-LKKTETQ, the N-acetylated fragment corresponding to residues 17–23 of thymosin β4. Commercial naming is inconsistent. Findings for the full-length 43-amino-acid peptide or unacetylated LKKTETQ cannot establish the fragment's clinical effects. Human recovery benefits are not established.
How strong is the evidence for TB-500?
PeptideHormone grades TB-500 at the "Preclinical" evidence tier — the evidence is largely animal or in-vitro, with human data thin or absent. It is catalogued as a community research peptide outside the approved-drug system, and the tier is an editorial judgment about the public literature that can change as the science does.
What is the half-life of TB-500?
The reported circulating half-life of TB-500 is Poorly characterized in humans.
Is TB-500 FDA-approved?
No — as of September 2026, TB-500 is sold outside the approved-drug system as research-use-only material, with no FDA approval for human use. A synthetic Tβ4 fragment with no drug development history; sold research-use-only. In July 2026 the Pharmacy Compounding Advisory Committee voted 8–6 with one abstention to recommend adding it to the 503A list, against FDA staff advice; the vote is non-binding and the status stands pending rulemaking. Status is US-centric and can change; check the FDA record for the current position.

In the literature

Live registry counts · retrieved
Registered trialsREF
11 recruiting
  • Ph 11
  • Ph 21
  • Ph 30
  • Ph 40
Open on ClinicalTrials.gov
PubMed recordsREF
26
Since 202210 · 38%
Open on PubMed

Searched as TB-500. Counts are search hits from the primary registries, not a curated set and not a grade – a measure of how much work exists on TB-500, not how it turned out.

Selected literature

Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.

  1. 1.Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance · Sports medicine (Auckland, N.Z.), 2026 · PMID 41966639
  2. 2.Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians · The American journal of sports medicine, 2026 · PMID 41476424

External references

TB-500 in the public knowledge graph — the same entity resolved across the authoritative chemistry and protein databases.