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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
Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians Narrative review 2026 TB-4 and its derivative TB-500 promoted 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
Thymosin beta 4: An emerging therapeutic candidate for kidney diseases Review 2026 Tβ4 and its N-terminal metabolite Ac-SDKP are described 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
The regenerative peptide thymosin β4 accelerates the rate of dermal healing in preclinical animal models and in patients review 2012 Tβ4 accelerated healing of full-thickness punch wounds in normal, steroid-treated, diabetic and aged rodents
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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0.5mg

Only vendor stocking this size on the VialBase roster.

5mg

10mg

Size unspecified

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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. Mayfield CK, Bolia IK, Feingold CL, Lin EH, Liu JN, Rick Hatch GF, Gamradt SC, Weber AE. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. The American Journal of Sports Medicine (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. Di H, Huang J, Zhang D, Ni F, Zheng R, Geng H. Thymosin beta 4: An emerging therapeutic candidate for kidney diseases. Peptides (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. Treadwell, T., Kleinman, H.K., Crockford, D. et al.. The regenerative peptide thymosin β4 accelerates the rate of dermal healing in preclinical animal models and in patients. Annals of the New York Academy of Sciences (2012). PMID: 23050815
  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