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healing · recovery

TB-500

Also known as: Thymosin Beta-4, TB4, Tβ4, Timbetasin
FDA: Not FDA-approved WADA: Prohibited
Last updated · 2026-06-19

TB-500 is a synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid peptide found in virtually all human and animal cells. It is the primary actin-sequestering molecule in mammalian cells and plays a central role in cell migration, wound healing, and tissue repair. Unlike BPC-157, which works best when injected near the injury site, TB-500 is fully systemic — inject it anywhere and it travels to sites of injury throughout the body. Originally isolated from thymus extract in the 1960s, Tβ4 is encoded by the X-linked TMSB4X gene and is one of the most highly conserved peptides in nature.

This content is for educational and research purposes only. VialBase does not provide medical advice. Consult a healthcare professional before using any peptide.

Molecular weight 4,963.44 Da
Half-life ~14 days
CAS number 885340-08-9
Route Subcutaneous · Intramuscular · Topical subcutaneous preferred
Where to buy TB-500 →BioLongevity Labs · save 15% code VIALBASE
📋 Full TB-500 dosage chart — reconstitution, tiered protocols & unit math → ⚠️ TB-500 side effects — common, serious & how to reduce them →
02

Dosing

DOSE RANGE 2000–5000 mcg
FREQUENCY 2x weekly
CYCLE LENGTH 4-8 weeks loading, 4 weeks maintenance

Systemic — inject anywhere, not site-specific like BPC-157

03

Mechanism

Upregulates actin, promotes cell migration via Akt/mTOR pathway, reduces inflammation, stimulates angiogenesis, modulates NF-κB

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Research summary

Study Type Year Key Finding
Therapeutic peptides: molecular signaling networks in orthopaedic medicine Narrative review 2026 TB-500 and TB-4 promote angiogenesis and tissue repair in preclinical models
A revised model of nuclear actin import: Importin 9 competes with cofilin, profilin, and RanGTP for actin binding Basic research 2026 Importin 9 competes with cofilin, profilin, and RanGTP for actin binding
The Tβ4-Ac-SDKP Axis in Kidney Disease: Renoprotective Efficacy Review Review 2026 Tβ4 and its metabolite Ac-SDKP act as dynamic mediators of renal injury and repair
Comparative Proteomic Analysis of the Secretome of Control and BRAF/MEK Inhibitor-Resistant Melanoma Cells Proteomic analysis 2026 Thymosin Beta-4 identified in secretome of BRAF/MEK inhibitor-resistant melanoma cells
Reparative Outcomes in Corneal Infection: Linking Adjunctive Tβ4 Treatment to Nerve Regeneration and Visual Function. Animal study 2026 Bacterial keratitis was induced in C57BL/6 mice by inoculating wounded corneas with Pseudomonas aeruginosa (ATCC strain 19660); four topical regimens (PBS, Tβ4 monotherapy, ciprofloxacin monotherapy, and adjunctive Tβ4 + ciprofloxacin) were given three times daily starting 24 hours post infection.
PEGylated thymosin β4 is a thiol-site-specific prodrug treating myocardial infarction in vivo. Preclinical in vivo study 2026 A modified prokaryotic expression system was developed to produce recombinant Tβ4 (rTβ4), which was then converted to the prodrug PEG-rTβ4 by single, thiol-site-specific PEGylation.
TB-500 (Thymosin Beta-4) for Cardiovascular Disease / ASCVD — — —
Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair animal study 2004 Thymosin beta-4 promotes cardiac cell survival after ischemia
Thymosin beta 4 promotes corneal wound healing and decreases inflammation in vivo following alkali injury animal study 2002 Tβ4 accelerated corneal wound healing after alkali burn
Thymosin beta 4 speeds corneal wound healing and decreases inflammation in the clinical setting review 2016 RGN-259 (Tβ4 eye drops) advanced through clinical trials for corneal healing
Thymosin β4, a multi-functional actin-sequestering protein involved in tissue repair review 2012 Comprehensive review of Tβ4 tissue repair mechanisms
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Stacking & interactions

Local + systemic healing synergy

Enhanced wound healing and tissue remodeling

GH-mediated recovery amplification

Stacks containing TB-500

Marquee

Glow Stack

GHK-Cu + BPC-157 + TB-500

 Marquee

KLOW Stack

GHK-Cu + KPV + BPC-157 + TB-500

 Marquee

Wolverine Stack

BPC-157 + TB-500

Athletic Recovery

BPC-157 + TB-500 + CJC/Ipamorelin

Recovery & Repair

BPC-157 + TB-500 + GHK-Cu

Tendon Armor

BPC-157 + TB-500 + Pentadecapeptide

28-day resets featuring TB-500

06

Sourcing

Current prices

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5mg

10mg

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Also vetted at
What bloodwork do I need?

Reference ranges are general guidelines. Consult your physician for interpretation.

PRE-CYCLE
  • CMP
  • CBC
  • CRP
DURING CYCLE
  • CBC
  • CRP
POST-CYCLE
  • CMP
  • CBC
Safety & Regulatory Status
FDA STATUS Not FDA-approved. Not on the 503A bulks list and not in any FDA interim category. An FDA advisory committee (PCAC) recommended it for the 503A bulks list on 2026-07-23; FDA has not adopted that recommendation and compounding TB-500 is not permitted.
WADA STATUS Prohibited (S0 — non-approved substances, effective 2011)

Regulatory status for TB-500 may change. Verify current status with your jurisdiction before use. This is not legal or medical advice.

Frequently Asked Questions

What is TB-500?
TB-500 is a synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid peptide found in nearly all human and animal cells and the main actin-sequestering molecule in mammalian cells. It plays a central role in cell migration, wound healing, and tissue repair. Unlike BPC-157, which works best near the injury site, TB-500 is fully systemic. It is not FDA-approved.
How does TB-500 work?
TB-500 binds G-actin to regulate the cytoskeleton, enabling cells to migrate rapidly to injury sites via the PI3K/Akt pathway. It also stimulates angiogenesis (new blood-vessel formation), reduces inflammation by modulating NF-κB signaling, and has antifibrotic effects through its Ac-SDKP metabolite. Together these actions support tissue repair and regeneration across multiple tissue types.
How is TB-500 dosed?
Commonly cited research protocols use a loading phase of about 2–5 mg twice weekly for 4–6 weeks, followed by roughly 2 mg once weekly for maintenance. Because TB-500 is systemic, it can be injected subcutaneously anywhere and does not require site-specific dosing like BPC-157. These figures reflect research protocols, not medical advice — consult a clinician.
What does the research on TB-500 show?
Thymosin Beta-4 is one of the most-studied peptides (over 1,000 PubMed entries), but most evidence is preclinical (animal models). It accelerated full-thickness wound closure in animal studies (Malinda et al., J Invest Dermatol 1999, PMID 10469335). The main human data come from Phase 2 corneal eye-drop trials (RGN-259). Cardiac, renal, and hair findings remain preclinical, so the human evidence tier is limited.
What is the difference between TB-500 and BPC-157?
Both are healing peptides often stacked together, but they act differently. TB-500 is fully systemic — injected anywhere, it travels to injury sites body-wide for tissue remodeling, angiogenesis, and cell migration. BPC-157 works best injected locally near the injury for targeted repair. Combining them is the most popular injury-recovery stack because they cover both systemic and local healing pathways.
What are the side effects of TB-500?
Published data report a generally favorable safety profile, with occasional transient head rush or lightheadedness, mild injection-site reactions, and temporary fatigue during loading. A theoretical concern is tumor promotion, since TB-500 promotes cell migration and angiogenesis, so people with active cancer should exercise extreme caution. Long-term human safety data are limited.
Is TB-500 FDA-approved?
No. TB-500 is not FDA-approved. It is also not on the 503A bulks list — the list of bulk drug substances compounding pharmacies may use — and it does not appear in any of FDA's interim Category 1, 2, or 3 lists. On July 23, 2026 an FDA advisory committee (PCAC) voted to recommend adding TB-500 to the 503A bulks list; FDA's own scientific reviewers had recommended against it. That vote is advisory and non-binding, FDA has not adopted it, and compounding TB-500 is not currently permitted. Any change would come through notice-and-comment rulemaking. WADA has prohibited it under category S0 (non-approved substances) since 2011, so athletes cannot use it. It is not a DEA-controlled substance.

References

  1. Various. Therapeutic peptides: molecular signaling networks in orthopaedic medicine. Orthopaedic Review (2026). PMID: 41476424
  2. Keplinger AJ, Srinivasan PA, Christensen SM, Suarez C, Ruthenburg AJ. A revised model of nuclear actin import: Importin 9 competes with cofilin, profilin, and RanGTP for actin binding. Journal of Biological Chemistry (2026). PMID: 41478570
  3. Various. The Tβ4-Ac-SDKP Axis in Kidney Disease: Renoprotective Efficacy Review. Renal Review (2026). PMID: 41570941
  4. Simiczyjew A, Surman M, Kot M, Przybyło ME, Nowak D. Comparative Proteomic Analysis of the Secretome of Control and BRAF/MEK Inhibitor-Resistant Melanoma Cells. Journal of Proteome Research (2026). PMID: 41742019
  5. Ebrahim AS, Liu L, Carion TW, et al.. Reparative Outcomes in Corneal Infection: Linking Adjunctive Tβ4 Treatment to Nerve Regeneration and Visual Function.. Investigative ophthalmology & visual science (2026). PMID: 42283548
  6. Peng H, Chai Y, Gong C, et al.. PEGylated thymosin β4 is a thiol-site-specific prodrug treating myocardial infarction in vivo.. Bioengineering & translational medicine (2026). PMID: 42394899
  7. TB-500 (Thymosin Beta-4) for Cardiovascular Disease / ASCVD.
  8. Bock-Marquette, I., Saxena, A., White, M.D. et al.. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature (2004). PMID: 15565145
  9. Sosne, G., Szliter, E.A., Barrett, R. et al.. Thymosin beta 4 promotes corneal wound healing and decreases inflammation in vivo following alkali injury. Experimental Eye Research (2002). PMID: 11950239
  10. Sosne, G., Dunn, S.P., Kim, C.. Thymosin beta 4 speeds corneal wound healing and decreases inflammation in the clinical setting. Expert Opinion on Biological Therapy (2016). PMID: 27537216
  11. Goldstein, A.L., Hannappel, E., Sosne, G. et al.. Thymosin β4, a multi-functional actin-sequestering protein involved in tissue repair. Expert Opinion on Biological Therapy (2012). PMID: 22074294