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tb-500

names a 7-amino-acid fragment of thymosin beta-4, but the vial you buy is a coin toss: fragment, full-length protein, or mislabeled. the COA mass is the only thing that knows.

tier A · healing · banned USEF 2014

verdict

the name means a 7-amino-acid fragment of thymosin beta-4, but vendor vials routinely contain the full 43-amino-acid protein instead, and the label does not tell you which. the molecule is real and the human proof is not.

if you're asking whether the fragment reproduces full thymosin beta-4 biology — the active site is preserved. half-life, tissue distribution, and pharmacology of a 7-aa peptide are not the same as a 43-aa protein. animal evidence (mostly on the full protein) is consistent for actin regulation, cell migration, angiogenesis, and wound healing. whether the fragment everyone is buying carries that biology forward at clinically relevant doses is the open question.

if you're asking about the wolverine stack (TB-500 + BPC-157) — this is the standard peptide-clinic healing pairing. zero controlled head-to-head data on either compound alone or the combination. user reports describe slower onset than BPC-157 with effects that build over weeks. BPC-157 skews toward gut and tendon; TB-500 reports skew toward muscle and broader soft-tissue. coherent story, persistent reports, no controlled trial.

if you're asking what the human evidence actually looks like — thin, and getting thinner. the full protein reached phase 3 in eye disease and missed: neurotrophic keratopathy (SEER-1, p=0.0656), dry eye (ARISE-3), and the european trial (SEER-3) again in june 2026. the injectable cardiac program (RGN-352) never enrolled a patient. nothing, fragment or protein, is approved anywhere. the parent biology is real; the human efficacy proof has not closed.

based on published evidence and disclosed clinical practice. not medical advice.

why A-tier

not actually thymosin β-4. it's a 7-amino-acid fragment of it, the actin-binding LKKTETQ sequence at positions 17-23. sold in the 2000s through the Australian equine veterinary market before crossing into human gray-market use. now widely discussed as BPC-157's companion in the "wolverine stack." the name refers to the actin-binding LKKTETQ fragment, but vendor vials frequently contain the full 43-amino-acid protein instead, and only the COA mass resolves which. either way the grade is the same. the preclinical base across skin, cornea, heart, and brain is large and reproducible, which keeps it above the lower tiers. but the human program has missed its pivotal phase 3 trials (SEER-1, ARISE-3, and SEER-3 in june 2026) and nothing is approved anywhere, which keeps it below S. A-tier: real biology, unfinished proof.

the core tension

the name and the vial disagree. 'TB-500' denotes the 7-amino-acid LKKTETQ fragment, but independent mass-spec of vendor products finds the contents inconsistent with the labels: some vials hold the fragment, many hold the full 43-amino-acid protein at ~4963 Da, and the same CAS number rides on both. only a third-party COA with a measured mass resolves it. and whichever you have, the human evidence is the same: a deep preclinical base, a clinical program that has now missed its phase 3s, and no approval anywhere.

what it is

TB-500 is a synthetic heptapeptide: Ac-LKKTETQ-OH, the actin-binding active site of thymosin beta-4 (a 43-amino-acid endogenous protein), acetylated at the N-terminus for stability. people call it 'thymosin beta-4' interchangeably. that's wrong. in this catalog, TB-500 means the short LKKTETQ-related peptide sold in research-peptide markets. most academic clinical literature is on the full 43-aa protein. don't collapse the two. no FDA-approved human or veterinary product exists.

what it does

the claimed mechanism follows the parent protein: actin sequestration, angiogenesis, cell migration, anti-inflammatory signaling, faster wound healing. whether a 7-aa fragment reproduces a 43-aa protein's biology is a fair question. the active site is preserved. half-life and tissue distribution are not. animal evidence (mostly on the full protein) is consistent. published human RCT data on the fragment specifically: zero.

origin

distributed in the 2000s by Medivet (New South Wales, Australia) for the equine veterinary market. racehorse injury recovery. Hong Kong Jockey Club Racing Laboratory published the first detection method in 2011. WADA banned it (class S2) the same year. there is no 'TB-500 lab' the way there's a Sikiric lab for BPC-157. it's a peptide sequence with a veterinary past, not a deliberate therapeutic program.

why researchers are interested

the 'wolverine stack', TB-500 plus BPC-157, became the standard peptide-clinic healing story. no head-to-head data on either compound or the combination. lifters and athletes research it for muscle and broader soft-tissue recovery. BPC-157's reputation skews more toward gut and tendon. user reports describe slower onset than BPC-157, with effects that build over weeks. the full-protein clinical track in ophthalmology (bacterial keratitis, neurotrophic keratopathy) anchors the parent biology in real human disease.

does it work

probably, with a large asterisk. the mechanism is plausible. animal evidence for full thymosin beta-4 supports the regenerative biology. community reports for musculoskeletal recovery are consistent. but the human program built on the full protein has missed its pivotal phase 3 trials: neurotrophic keratopathy (SEER-1, p=0.0656), dry eye (ARISE-3), and the european trial (SEER-3) in june 2026. the injectable cardiac program (RGN-352) never enrolled a patient. nothing is approved anywhere. and the heptapeptide the name refers to has no controlled human trial of its own. A-tier on mechanism and consistent reports. not S, because S requires drug-tier evidence the molecule does not yet have.

claims vs the data

  • TB-500 is the same thing as thymosin beta-4 — depends on the vial — the NAME 'TB-500' denotes the 7-aa LKKTETQ fragment, chemically distinct from the 43-aa protein. but independent mass-spec finds many vendor vials labeled 'TB-500' actually contain full-length thymosin beta-4 (~4963 Da), and the same CAS number is used for both. 'is it Tβ4' is answered by the COA mass, not the label.
  • heals soft tissue injuries — weak — animal studies and veterinary use suggest wound healing acceleration. human controlled data nonexistent.
  • works synergistically with BPC-157 — unverified — the "wolverine stack" combination is common in peptide clinics but has no formal head-to-head comparison to either compound alone.
  • WADA-banned because it works — partially true — WADA banned TB-500 based on animal evidence of anabolic potential and widespread equine use. effect size in humans is not established.
  • safer than steroids — weak — no documented serious adverse events in the limited human use. but "no documented AEs" with minimal human data doesn't equal "safer."
  • accelerates wound recovery by 2-3x — overreach — typical veterinary study numbers. does not translate 1:1 to human injury recovery.
  • TB-500 injury recovery is clinically proven — weak — The broader thymosin beta-4 biology is real, and TB-500 metabolism/detection work is legitimate, but direct clinical injury-recovery evidence for retail TB-500 remains thin. The claim is plausible, not proven.

key facts

  • molecular formula: C₄₃H₇₅N₁₃O₁₇
  • molecular weight: 889.0 g/mol (heptapeptide)
  • amino acids: 7 (N-acetylated LKKTETQ)
  • half-life: ~0.5 to 2 hours (human phase-1 PK, PMID 34346165; dose-dependent), same as full thymosin beta-4 when that is what the vial holds; the bare heptapeptide clears faster
  • type: synthetic fragment of thymosin β-4
  • CAS: 77591-33-4
  • 7 aa vs full tβ-4 (43 aa)
  • 2011 banned by WADA
  • 2011 hong kong doping detection method
  • 0 FDA-approved indications

frequently asked questions

What is TB-500?

TB-500 is a market term used inconsistently. In this reference it means the short N-acetylated LKKTETQ thymosin beta-4-related fragment, while much of the academic clinical literature is on full-length thymosin beta-4. It is sold as a research chemical for tissue-repair and anti-inflammatory applications, primarily in the sports recovery community.

What does TB-500 do?

TB-500 has demonstrated wound-healing, tissue-repair, and angiogenic effects in preclinical studies, primarily through actin regulation and cell migration. Community users report accelerated recovery from muscle and tendon injuries. Human clinical trial evidence remains limited.

How is TB-500 typically administered?

TB-500 shows up in injectable research-peptide culture, usually under the tissue-repair banner. The clinical literature that actually exists is mostly on full-length thymosin beta-4 in topical ophthalmic or wound settings. There is no FDA-approved human TB-500 dosing framework.

What are the side effects of TB-500?

Community reports of TB-500 are generally clean, users rarely report systemic side effects. Occasional injection-site soreness and transient fatigue are the most commonly cited adverse events. Because human clinical trials are limited, the long-term side effect profile is not fully characterized.

Is TB-500 FDA approved?

No. TB-500 is not FDA-approved for any indication. It is classified as a research chemical and is prohibited in competition under the WADA code (S2 category, peptide hormones, growth factors, and related substances).

How much does TB-500 cost?

TB-500 has no clinical retail price as it is not a prescription drug. On the research-chemical market it tends to price higher than most peptides due to synthesis complexity. Some wellness clinics have sold compounded TB-500 packages, but the pricing story is not a validation story.

related peptides

  • bpc+tb blend — the wolverine blend, TB+BPC in one vial
  • bpc-157 — paired as the local/angiogenic half
  • glow — contains TB-500 as a blend component
  • klow — contains TB-500 as a blend component

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.