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Peptide Evidence Registry

Tissue repair

TB-500 / Thymosin beta-4

A genuine biological protein with real research history, and a separate online product that is not quite the same thing.

L2Animal / lab studiesResearch / unapproved supplyUnclear
How settled this rating is:
very-low confidence in the current evidence rating
Routes studied:
Ophthalmic, Topical · Subcutaneous injection (marketed but never approved)
Also known as:
TB4, Tβ4, thymosin beta-4 fragment
Last reviewed:
2026-09-18
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Evidence passport

TB-500 / Thymosin beta-4

A one-screen evidence identity for this compound. These fields describe research maturity, confidence and legal status. They are not a safety guarantee, efficacy percentage or recommendation.

Reviewed 2026-09-18
Evidence level
L2Animal / lab studies
Confidence
Very low confidence in rating
Regulatory status
Research / unapproved supply
Development status
Unclear

Evidence strength

Human efficacy evidence18 of 100 evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Human safety evidence20 of 100 evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

The 0-100 values rate the strength and maturity of evidence, not how effective or safe the compound is.

Evidence base
Mostly animal and laboratory research
Furthest established stage
Not established
Human research maturity
Preclinical for musculoskeletal claims; limited clinical study in narrow indications
Source curation
Sources fully curated

Routes recorded

OphthalmicTopicalSC injection· unapproved

Most of this evidence comes from animals and cells

The supporting research for TB-500 / Thymosin beta-4 is predominantly preclinical (Level 1–2). That is a legitimate starting point for science and a poor basis for personal decisions. Human results are not simply a scaled-up version of mouse results.

Overview

Human efficacy evidence strength18 of 100 evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Preclinical (animal / lab) evidence strength72 of 100 evidence strength

Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.

Human safety evidence strength20 of 100 evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

How to read these scores

Every number here rates the evidence, not the compound. They are editorial 0-100 strength ratings, not percentages, and not a rating out of five stars.

  • Human efficacy evidence strength — Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
  • Preclinical evidence strength — Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.
  • Human safety evidence strength — Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number. A score of 80 does not mean “80% safe”.
  • Evidence level (L0-L5) — the strongest type of study behind the compound, from anecdote (L0) to large replicated human trials (L5). It is a description of the study evidence, not a quality, safety or recommendation rating.
  • Confidence — how likely we think it is that this rating changes as new research lands. Low confidence means the picture is unsettled, not that the compound is bad.

None of these ratings is medical advice, a safety guarantee, or a recommendation to use anything. How we grade evidence.

How far human research has progressed: Preclinical for musculoskeletal claims; limited clinical study in narrow indications

Routes & formulations

Studied / approved routes

OphthalmicTopical

Marketed / research routes — never approved

SC injection· unapproved

Clinical study of thymosin beta-4 used ophthalmic and topical/dermal formulations in narrow indications. 'TB-500' sold online is typically an injectable fragment — an unapproved route and product with no controlled human evidence. Evidence for one route or molecule does not transfer to the other.

Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.

Peptide lifecycle

  1. Discovery

  2. Preclinical

  3. Phase I

  4. Phase II

  5. Phase III

  6. Approved

UnclearFurthest stage not established in our curated record

Thymosin beta-4 has been studied clinically in narrow ophthalmic and wound indications; there is no established development programme for the 'TB-500' fragment sold online.

What it is

Thymosin beta-4 is a naturally occurring actin-binding protein involved in cell migration and wound repair. 'TB-500' usually refers to a shorter synthetic fragment sold as a research chemical. The distinction matters and is routinely blurred in marketing.

What people claim

  • Accelerates soft-tissue and tendon healing
  • Reduces scar tissue
  • Improves flexibility and recovery in athletes

What the evidence actually says

Thymosin beta-4 has credible cell-biology and animal evidence for wound healing and cell migration, and has been studied clinically in narrow indications such as dry eye and certain wounds. Controlled human evidence for sports injury recovery — the reason most people search for it — does not exist.

Related evidence

Useful next reads based on this compound — not recommendations.

Human evidence

  • Clinical studies of thymosin beta-4 in specific ophthalmic and dermal wound indications; not translatable to tendon-repair marketing.
  • No controlled human trials supporting athletic injury-recovery claims for TB-500.
  • The September 2026 BPC-157 clinical-note preprint (not peer reviewed) documented TB-500 co-use in 12.9% of 1,039 confirmed BPC-157 users. That records co-use in clinical notes only: it does not identify what material was used, whether the peptides were combined in one vial, or that any outcome was caused by TB-500 or by the combination. No evidence level moves on the strength of it.

Preclinical evidence

  • Animal models of cardiac, dermal and corneal repair.
  • Cell studies of actin sequestration, migration and angiogenesis.

Animal and cell findings are Level 1–2 evidence.

Mechanism and pathways

  • Binds G-actin, regulating cytoskeletal dynamics and cell migration.
  • Promotes endothelial cell migration and angiogenesis.
  • Modulates inflammatory signalling in injury models.

Safety and unknowns

  • No systematic human safety dataset for the injectable research-chemical form.
  • Banned by anti-doping authorities; a positive test carries real consequences.
  • Unapproved supply quality is a distinct risk from the molecule's own pharmacology.

Cancer relevance

This section covers questions raised by how the compound works in the body, plus anything regulators and trial teams keep an eye on. It is not a statement that this compound causes cancer — for most compounds here, no human data exist in either direction.

Theoretical / mechanistic concern only

Thymosin beta-4 promotes angiogenesis and cell migration, and elevated expression has been described in some tumour contexts. That is a mechanistic and observational concern worth naming honestly; it is not proof that administering it causes cancer in humans. There is no human evidence either way.

Regulatory status

Regulatory decisions apply to specific jurisdictions, products, formulations and indications. An approval elsewhere is not automatically an approval in your country.

Check the regulatory note and linked primary sources for jurisdiction-specific details.

Not an approved medicine for injury recovery. Thymosin beta-4 has been studied clinically in specific ophthalmic and wound contexts; 'TB-500' as sold online is typically a synthetic fragment marketed outside medical supply. FDA's Pharmacy Compounding Advisory Committee considered thymosin beta-4-related substances in July 2026 for possible inclusion on the 503A Bulks List. Its recommendations are non-binding: this is a compounding-policy process, not FDA drug approval, validation of efficacy claims or blanket legalisation. It is also prohibited in sport.

Evidence grade

L2Animal / lab studiesVery low confidence in rating

Documented compound-specific animal or laboratory outcome findings, without qualifying human evidence for the assessed benefit.

What would change our rating?

  • Controlled human trials in musculoskeletal injury.
  • Human safety and pharmacokinetic data for the fragment actually sold as TB-500.

References and sources

Source transparency

A provenance snapshot of this profile. Counts show what kinds of sources are cited, not how much scientific weight each source deserves.

Sources fully curated
Last editorial review
2026-09-18
Recently reviewed · 28 days ago
Linked curated sources
4
Sources still pending
0
External specialist reviews
0
None recorded for this profile
Regulatory / label: 3Preprint — not peer reviewed: 1

Review provenance

Registry editorial review: Colin Jackson-White, creator and editor, who is not a doctor or clinician. External specialist review is credited only when a named reviewer has completed a review of this exact profile.

Literature-discovery and AI tools may help locate or challenge candidate evidence, but they are not counted as evidence sources here. Registry judgements are tied to the underlying papers, trial records, regulator documents and official study records.

Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.

Evidence change history

These entries record changes to our assessment of the published evidence — not changes to the compound itself.

No recorded changes yet. Baseline position set on 2026-09-18.

Related claims we’ve checked — in full

Claim verdict

Tissue repair

Partly supportedL2Animal / lab studies

“TB-500 and thymosin beta-4 are the same thing.”

This verdict applies to the exact claim above. It is not a verdict on the compound overall, a safety guarantee, or a recommendation to use it.

Registry verdict

Partly supported — related, but not interchangeable, and marketing blurs it deliberately.

Why this verdict

  • Thymosin beta-4 is the full naturally occurring protein with a genuine research history.
  • 'TB-500' typically denotes a shorter synthetic fragment sold as a research chemical.
  • Citing thymosin beta-4 clinical work to sell TB-500 for tendon repair is a category error.