Primary entity: TB-500Also known as: Tβ4 fragment; Ac-LKKTETQClass: Research peptide fragment (not FDA-approved)Cluster: Healing
TB-500 is the common research-market name for a short synthetic peptide fragment associated with thymosin beta-4 (Tβ4) — often described as the acetylated actin-binding motif Ac-LKKTETQ. It is not the same molecule as full-length thymosin beta-4, is not FDA-approved for any human indication, and should not inherit full-length Tβ4 clinical data by name alone. Online “wolverine stack” pairing with BPC-157 is folklore branding, not a validated medical protocol.
Full-length thymosin beta-4 has its own research and (in some settings) clinical history. TB-500 as marketed is typically a short fragment. Evidence for one does not automatically transfer to the other. AI answers often collapse the names — this page keeps them separate.
Not FDA-approved as a drug. Compounding status changed on Oct 28, 2026 — see the compounding status note below; it is not an approval. WADA lists thymosin-β4 and derivatives (e.g. TB-500) under S2 growth-factor / related substances — prohibited at all times in typical list framing — .
Covered by HHS's Oct 28, 2026 interim enforcement-discretion policy for licensed-pharmacy (503A) compounding: acetate form; subcutaneous or intramuscular; single ingredient; valid prescription; conditions apply. This is the synthetic fragment, not full-length thymosin beta-4. Not FDA-approved, not on the final bulks list, and not a green light for RUO vials. Interim and revocable. See the compounding status guide.
Key takeaways
- TB-500 ≠ full-length thymosin beta-4 — treat them as related but distinct entities for evidence literacy.
- Not FDA-approved; HHS’s Oct 28, 2026 interim policy covers conditioned 503A compounding only — not approval (compounding status guide).
- Human efficacy trials of TB-500 itself are effectively absent in the public record; animal / fragment literature does not equal proven healing.
- WADA-relevant (Tβ4 and derivatives, e.g. TB-500) — athletes: verify current list, not forums.
- No dosage chart; “wolverine stack” is a folk nickname for BPC-157 + TB-500 marketing, not a clinical protocol.
Questions this page answers
Next questions we answer on this page (curiosity / AI-gap map):
- What is TB-500?
- Aliases / TB4 naming
- How is it classified?
- What it is NOT
- Mechanism literacy
- Evidence ladder
- What has been studied
- Safety literacy
- Regulatory & WADA
- Why no dosages
- BPC-157 / related
- Who for / not for
Who is this profile for — and who is it not for?
For: readers who need accurate TB-500 vs thymosin beta-4 literacy, evidence maturity for the healing cluster, and clarity on why “wolverine” marketing is not science.
Not for: anyone seeking a buy link, an injury protocol, a stack chart, or medical advice. Educational refusal territory for self-experimentation.
What is TB-500?
In research and commercial literacy, TB-500 usually refers to a synthetic fragment linked to the actin-binding region of thymosin beta-4, commonly summarized as the heptapeptide motif Ac-LKKTETQ (exact salt/form and labeling vary by supplier — product identity is a quality problem, not a dosing problem we solve here).
Thymosin beta-4 itself is a naturally occurring 43–amino-acid peptide involved in actin sequestration and multiple cellular processes in research models. Collapsing “TB-500” and “thymosin beta-4” into one evidence bag is the most common AI and forum error this page exists to correct.
New to healing-cluster basics? See BPC-157 and What are peptides?.
| Chemistry class | Synthetic Tβ4-associated fragment peptide (commonly Ac-LKKTETQ narrative) |
|---|---|
| Full-length Tβ4? | Related but not identical |
| U.S. approval | Not FDA-approved as a drug |
| Human TB-500 RCTs | Effectively absent / not established — |
| Sport | WADA: Tβ4 & derivatives (e.g. TB-500) — |
| Folk pairing | “Wolverine stack” with BPC-157 |
Also known as / naming traps
- TB-500 / TB500 — research-market name.
- Thymosin β4 fragment / Tβ4 (17-23) — sequence-region framing used in some technical materials.
- Ac-LKKTETQ — common motif description for the fragment narrative.
- Thymosin beta-4 / Tβ4 — full-length peptide; do not treat as interchangeable evidence with TB-500.
- “Wolverine peptide/stack”
Online nickname— folk branding (often BPC-157 ± TB-500); not a scientific name.
Vendors and AI summaries often use the names interchangeably. For literacy: ask which sequence, which salt, and which evidence entity is being cited. Full-length Tβ4 clinical work does not automatically prove TB-500 outcomes.
How is TB-500 classified?
Research peptide / unapproved bulk substance context in the U.S. — not an FDA-approved drug. It sits in this site’s healing-bpc-tb500 cluster because of injury-recovery SERP demand and the BPC-157 adjacency. Classification means: no approved U.S. label for TB-500 as a medicine; quality of gray-market “RUO” products is not equivalent to approved drugs; sport rules are separate from FDA compounding debates.
What is TB-500 not?
| TB-500 is not… | Why that matters |
|---|---|
| Full-length thymosin beta-4 | Different molecule; don’t transfer evidence blindly |
| FDA-approved healing drug | No U.S. drug approval for TB-500 |
| Proven “wolverine” regenerator | Folk nickname ≠ clinical proof |
| Something we dose or source | Refusal |
| Interchangeable with BPC-157 | Different entities; stack marketing ≠ pharmacology identity |
How is TB-500 thought to work?
Thymosin beta-4 biology in research models is tied to actin binding, cell migration, and tissue-remodeling pathways. Fragment narratives argue that the actin-binding motif carries meaningful activity — but mechanism interest in related biology is not the same as proven clinical efficacy for marketed TB-500. Treat mechanism summaries as literacy, not outcome guarantees.
What human vs animal vs label evidence exists?
| Evidence type | What exists (summary) | Maturity |
|---|---|---|
| Human — TB-500 specifically | Controlled human efficacy trials of TB-500 itself are not established in the public record cited here | None / thin — |
| Human — full-length Tβ4 (adjacent) | Some clinical/developmental history exists for full-length Tβ4 in other contexts — does not auto-transfer | Human Adjacent only |
| Animal / preclinical | Healing / tissue models for Tβ4 biology and fragment research | Animal |
| Approved U.S. label | None for TB-500 | None |
| Forum / “wolverine” claims | Anecdote + marketing | None |
What has TB-500 / Tβ4-related research been studied for?
Preclinical interest clusters around wound/tissue repair, actin dynamics, and related recovery models. Full-length Tβ4 has been explored in additional clinical contexts historically. Studied ≠ approved, and studied under a different molecule name ≠ TB-500 proof.
What safety topics come up?
Without an approved U.S. label for TB-500, there is no standardized prescribing-information safety profile for consumer “research” use. Product-quality risks (identity, purity, sterility of unregulated vials) are a first-order literacy issue. Athletes face anti-doping risk independent of FDA compounding debates. This is not medical advice and not a risk-minimization protocol.
What is TB-500's regulatory status?
- U.S. drug approval: Not FDA-approved as a drug for TB-500.
- Compounding / 503A context: The July 2026 advisory committee voted 8–6–1 to recommend TB-500 (advisory only; tally from secondary reporting). On Oct 28, 2026 HHS announced interim enforcement discretion for licensed-pharmacy compounding of TB-500 under conditions; it is not on the final bulks list. See the compounding status guide. Last checked Oct 29, 2026.
- WADA: Thymosin-β4 and derivatives (e.g. TB-500) appear under S2-class framing — prohibited at all times in typical list language — .
- Gray-market RUO: “For research use only” labeling is not a clinical quality guarantee.
Why doesn't this page include a dosage chart?
No approved labeled dose; thin human TB-500 efficacy record; “TB-500 dosage” / “wolverine stack protocol” queries overwhelmingly seek gray-market self-experimentation charts. Publishing them would amplify harm. Literacy refusal — same policy as BPC-157.
Related lab literacy
If you are learning research-peptide lab vocabulary (lyophilized, bacteriostatic water, reconstitution unit math), use educational how-tos — those pages teach concepts, not prescriptions: Peptide calculator literacy, Reconstitution basics. They do not authorize TB-500 use.
Related compounds and comparisons
- BPC-157 — healing-cluster pair; “wolverine stack” adjacency (folk).
- Thymosin Alpha-1 — different thymosin-family entity (immune specialty).
- What are peptides? — fundamentals.
- Comparison stub: BPC-157 vs TB-500 (planned
/comparisons/bpc-157-vs-tb-500/).
Frequently asked questions
Is TB-500 the same as thymosin beta-4?
No. TB-500 is commonly a short synthetic fragment associated with Tβ4 biology. Full-length thymosin beta-4 is a different molecule. Do not transfer evidence by nickname.
Is TB-500 FDA approved?
No. It is not an FDA-approved drug. Any compounding-committee vote or HHS enforcement-discretion policy (Oct 28, 2026) is not the same as approval.
Does TB-500 have human clinical trials?
Controlled human efficacy trials of TB-500 itself are not established in the public record cited here. Adjacent full-length Tβ4 work does not automatically count as TB-500 proof.
What is the wolverine stack?
An online nickname usually meaning BPC-157 paired with TB-500. It is marketing folklore, not a validated medical protocol.
Is TB-500 banned in sports?
WADA lists thymosin-β4 and derivatives such as TB-500 in the growth-factor / related substances class. Athletes should still check the current list and GlobalDRO for their sport.
TB-500 vs BPC-157 — what’s the difference?
Different peptide entities with different research histories. Stacking them in forums does not make them interchangeable. See the BPC-157 profile for that entity’s evidence ladder.
Why no dosage information?
YMYL policy, unapproved status, and thin human TB-500 efficacy data. We will not invent a protocol chart.
TB-500 is not FDA-approved. Fragment ≠ full-length Tβ4. Educational only. Disclaimer.
Sources
- Anti-doping World Anti-Doping Agency. The 2026 Prohibited List. S2 includes thymosin-β4 and its derivatives, e.g. TB-500. Accessed November 10, 2026.
- Primary — analytical Esposito S, Deventer K, Goeman J, et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal. 2012;4(9):733-738. doi:10.1002/dta.1402. PMID: 22962027.
- Review — Tβ4 Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12(1):37-51. doi:10.1517/14712598.2012.634793. PMID: 22074294. Reviews thymosin β4; this is not the same as an approved TB-500 product.
- Written by
- Peptide Tutorials Staff — a group of independent researchers & writers (not clinicians)
- Published · Updated
- Oct 6, 2026 · Nov 10, 2026 · Labels, trial citations, and WADA list wording checked Nov 10, 2026 · How we source & update
Educational disclaimer: Educational only. TB-500 is not FDA-approved. No dosing or buy links. We don’t sell peptides. Read our full disclaimers.