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RUO · Research Use Only⚠ Cancer Concern+2 more★ Popular

TB-500

A synthetic fragment of thymosin beta-4. We read all 60 studies. The protocol is below.

Updated 19 May 2026Read 13 minEvidence ●○○○○Citations 60
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Free — puts TB-500 on your decision board.

The TB-500 Report · $19

Everything you need to start: dose, sourcing, safety, our verdict.

One purchase · yours forever

Built from 60 cited studies.

Status
Research-only
Class
Cancer Concern
Evidence
1/ 5●○○○○
Randomized human trials (TB-500 fragment)
$19 ↓
Trials of full-length TB-4 (different molecule)
$19 ↓
Animal studies
$19 ↓
⚠ Cancer Concern
Read this if
  • you tore something, BPC-157 didn't fully resolve it, and your gym friends are stacking the two
  • you're an untested-sport athlete (powerlifting, strongman) and the WADA flag doesn't apply to you
  • you've worked with horses and recognize the equine-veterinary pedigree
Skip this if
  • you have a personal or family history of cancer — angiogenesis plus cell migration is the tumor toolkit
  • you compete in any tested sport — WADA-banned
  • you want randomized human data — there is essentially none
The 4 ways you can buy TB-500
Brand
✗
Not available
No FDA-approved TB-500; same regulatory zone as BPC-157.
Compounded 503A
⚠
Rx
$200–$400/mo where still sold
Some compounders ship under contested legal interpretations; pharmacies still selling are legally …
RUO (research-only)
✓
Sold 'for research only'
$80–$200/mo
The dominant supply; some vendors sell full Tβ4 at fragment prices, identity by mass spec is the o…
Gray market
✓
Unregulated overseas import
$15–$35/mo
Crypto/Wise pay, identity-uncertain; WADA-prohibited for tested athletes regardless of source.
Click any lane for the full Sourcing breakdown.
First 90 days · TB-500
Weeks 1–2
Nothing perceptible. The healing-acceleration effect — if it's going to work — isn't a week-one signal. If you 'feel something' immediately, that's expectation, not the peptide.
Weeks 4–8
Subtle improvement on the target injury if it's going to work. Range of motion, less morning stiffness, less acute pain on load.
Week 12 — decide
Honest decision point. Either the injury is materially better than the no-peptide trajectory would have been, or it isn't. The clinical literature in humans is thin enough that your n=1 trial IS the evidence base.
Quit if
  • Any unusual symptoms — especially relevant if you have a personal or family cancer history (angiogenesis mechanism for BPC-157, TB-500).
  • 12 weeks with no perceived improvement vs the no-peptide trajectory.
  • New pain or symptoms at injection site that don't resolve in 48 hours.
Identity

What it is.

TB-500 is a synthetic fragment of Thymosin Beta-4, a small protein found in nearly every tissue in the body. The full Thymosin Beta-4 molecule is involved in cell migration, wound repair, and new blood vessel formation. TB-500 is the marketed -shop version of the active region.

It's sold strictly as a research chemical (RUO) in the US. It's not approved for any human indication anywhere. The full protein has been studied in early human trials for things like chronic wounds and dry eye, but those are different molecules with different pharmacokinetics than what's being injected in gyms.

It sits in the same cultural slot as BPC-157 — "recovery " — and is often stacked with it. The animal data is real. The human data is not.

TL;DR

TL;DR. 30-second version.

The compressed verdict — what TB-500 actually is, what the human evidence shows, and the watch-for in three bullets. Locked.

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Mechanism

Mechanism.

Mechanism · in the TB-500 report

How the molecule actually works — receptor profile, downstream signaling, what to expect mechanistically.

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Evidence

Evidence. What we actually know in humans.

Evidence · in the TB-500 report

The trial breakdown — phase, n, primary endpoint, who funded, what hit, what didn't.

Get the report · $19 ↓
Human-Evidence Factbox
Randomized human trials (TB-500 fragment)
$19 ↓
Trials of full-length TB-4 (different molecule)
$19 ↓
Animal studies
$19 ↓
WADA status
$19 ↓
Horse-racing ban
$19 ↓
Years of off-label use
$19 ↓
Stack with BPC-157
$19 ↓
Major adverse events flagged
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Dose

Dose. The actual protocol.

Dose · in the TB-500 report

The specific protocol — dose, titration schedule, cycle pattern, frequency, route.

We read 60 studies to write this report.
Get the report · $19 ↓
Sourcing

Sourcing. Where the cohort actually buys.

Sourcing · in the TB-500 report

Sourcing breakdown — vendor methodology, red flags, our published test results, COA checklist.

We read 60 studies to write this report.
Get the report · $19 ↓
Safety

Safety. Side effects.

Safety · in the TB-500 report

The watch-for list — contraindications, drug interactions, monitoring labs, when to stop.

Get the report · $19 ↓
Editorial Position

Editorial position.

Editorial Position · in the TB-500 report

Our editorial position — explicit yes / no / depends, with the reasoning behind it.

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Citations

Citations.

  1. 01Goldstein AL, et al. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert opinion on biological therapy. 2012;12(1):37-51. PMID: 22074294.
  2. 02Bubb MR. Thymosin beta 4 interactions. Vitamins and hormones. 2003;66:297-316. PMID: 12852258.
  3. 03Rahman OF, et al. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions. Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews. 2026;10(1). PMID: 41490200.
  4. 04Hannappel E. beta-Thymosins. Annals of the New York Academy of Sciences. 2007;1112:21-37. PMID: 17468232.
  5. 05Sun HQ, et al. The beta-thymosin enigma. Annals of the New York Academy of Sciences. 2007;1112:45-55. PMID: 17495248.
+Show all 60 citations
  1. 06Chen X, et al. Identification of glutamine as a potential therapeutic target in dry eye disease. Signal transduction and targeted therapy. 2025;10(1):27. PMID: 39837870.
  2. 07Zeng PM, et al. Thymosin beta 4 as an Alzheimer disease intervention target identified using human brain organoids. Stem cell reports. 2025;20(9):102601. PMID: 40816274.
  3. 08Faa G, et al. Thymosin β(4) and β(10) Expression in Human Organs during Development: A Review. Cells. 2024;13(13). PMID: 38994967.
  4. 09Pipes GT, et al. Cardioprotection by Thymosin Beta 4. Vitamins and hormones. 2016;102:209-26. PMID: 27450736.
  5. 10Belsky JB, et al. Thymosin beta 4 regulation of actin in sepsis. Expert opinion on biological therapy. 2018;18(sup1):193-197. PMID: 29508629.
  6. 11Bock-Marquette I, et al. Thymosin beta-4 denotes new directions towards developing prosperous anti-aging regenerative therapies. International immunopharmacology. 2023;116:109741. PMID: 36709593.
  7. 12Low TL, et al. Thymosin beta 4. Methods in enzymology. 1985;116:248-55. PMID: 4088087.
  8. 13Maar K, et al. Thymosin Beta-4 Modulates Cardiac Remodeling by Regulating ROCK1 Expression in Adult Mammals. International journal of molecular sciences. 2025;26(9). PMID: 40362372.
  9. 14Sosne G. Thymosin beta 4 and the eye: the journey from bench to bedside. Expert opinion on biological therapy. 2018;18(sup1):99-104. PMID: 30063853.
  10. 15Kim J, et al. Potential role of thymosin Beta 4 in liver fibrosis. International journal of molecular sciences. 2015;16(5):10624-35. PMID: 26006229.
  11. 16Kim J, et al. Thymosin Beta 4 Is a Potential Regulator of Hepatic Stellate Cells. Vitamins and hormones. 2016;102:121-49. PMID: 27450733.
  12. 17Sosne G, et al. Thymosin beta 4: A potential novel adjunct treatment for bacterial keratitis. International immunopharmacology. 2023;118:109953. PMID: 37018981.
  13. 18Othman O, et al. Thymosin beta 4 prevents systemic lipopolysaccharide-induced plaque load in middle-age APP/PS1 mice. International immunopharmacology. 2023;117:109951. PMID: 36878045.
  14. 19Song K, et al. Thymosin beta 4 attenuates PrP(106-126)-induced human brain endothelial cells dysfunction. European journal of pharmacology. 2020;869:172891. PMID: 31877278.
  15. 20Kim S, et al. Thymosin Beta 4 Protects Hippocampal Neuronal Cells against PrP (106-126) via Neurotrophic Factor Signaling. Molecules (Basel, Switzerland). 2023;28(9). PMID: 37175330.
  16. 21Bako P, et al. Thymosin beta-4 - A potential tool in healing middle ear lesions in adult mammals. International immunopharmacology. 2023;116. PMID: 38706788.
  17. 22Zhang Y, et al. Recombinant human thymosin beta 4 improves ischemic cardiac dysfunction in mice and patients with acute ST-segment elevation myocardial infarction after reperfusion. Cardiovascular research. 2025;121(17):2747-2758. PMID: 41229390.
  18. 23Vasilopoulou E, et al. Loss of endogenous thymosin β(4) accelerates glomerular disease. Kidney international. 2016;90(5):1056-1070. PMID: 27575556.
  19. 24Tan WKY, et al. Sources of variability in quantifying circulating thymosin beta-4: literature review and recommendations. Expert opinion on biological therapy. 2018;18(sup1):141-147. PMID: 29502471.
  20. 25Wirsching HG, et al. Thymosin β 4 gene silencing decreases stemness and invasiveness in glioblastoma. Brain : a journal of neurology. 2014;137(Pt 2):433-48. PMID: 24355709.
  21. 26Jiang Y, et al. Potential role of thymosin beta 4 in the treatment of nonalcoholic fatty liver disease. Chronic diseases and translational medicine. 2017;3(3):165-168. PMID: 29063072.
  22. 27Zhang X, et al. Enhancing fat graft survival: thymosin beta-4 facilitates mitochondrial transfer from ADSCs via tunneling nanotubes by upregulating the Rac/F-actin pathway. Free radical biology & medicine. 2025;228:281-298. PMID: 39761767.
  23. 28Gao X, et al. Thymosin Beta-4 Induces Mouse Hair Growth. PloS one. 2015;10(6):e0130040. PMID: 26083021.
  24. 29Nachmias VT, et al. Thymosin beta 4 (T beta 4) in activated platelets. European journal of cell biology. 1993;61(2):314-20. PMID: 8223720.
  25. 30Low TL, et al. Chemical characterization of thymosin beta 4. The Journal of biological chemistry. 1982;257(2):1000-6. PMID: 7054160.
  26. 31Sosne G, et al. Thymosin Beta 4: A Potential Novel Therapy for Neurotrophic Keratopathy, Dry Eye, and Ocular Surface Diseases. Vitamins and hormones. 2016;102:277-306. PMID: 27450739.
  27. 32Larsson LI, et al. Localization of thymosin beta-4 in tumors. Annals of the New York Academy of Sciences. 2007;1112:317-25. PMID: 17495241.
  28. 33Smart N, et al. Thymosin beta-4 is essential for coronary vessel development and promotes neovascularization via adult epicardium. Annals of the New York Academy of Sciences. 2007;1112:171-88. PMID: 17495252.
  29. 34Zalvide JB, et al. Regulation of thymosin beta 4 mRNA levels during cell proliferation. Cell proliferation. 1995;28(2):85-91. PMID: 7534483.
  30. 35Lin C, et al. Thymosin beta-4 participate in antibacterial immunity and wound healing in black tiger shrimp, Penaeus monodon. Fish & shellfish immunology. 2023;141:109065. PMID: 37689229.
  31. 36Cierniewski CS, et al. Adhesive and proteolytic phenotype of migrating endothelial cells induced by thymosin beta-4. Annals of the New York Academy of Sciences. 2007;1112:123-39. PMID: 17495245.
  32. 37Badamchian M, et al. Thymosin beta(4) reduces lethality and down-regulates inflammatory mediators in endotoxin-induced septic shock. International immunopharmacology. 2003;3(8):1225-33. PMID: 12860178.
  33. 38Yu FX, et al. Thymosin beta 10 and thymosin beta 4 are both actin monomer sequestering proteins. The Journal of biological chemistry. 1993;268(1):502-9. PMID: 8416954.
  34. 39Davison G, et al. The potential use and abuse of thymosin β-4 in sport and exercise science. Journal of sports sciences. 2013;31(9):917-8. PMID: 23421910.
  35. 40Sosne G, et al. Thymosin beta-4 and the eye: I can see clearly now the pain is gone. Annals of the New York Academy of Sciences. 2007;1112:114-22. PMID: 17495249.
  36. 41Kuo CY, et al. Aberrant Expression of Thymosin Beta-4 Correlates With Advanced Disease and BRAF V600E Mutation in Thyroid Cancer. The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society. 2022;70(10):707-716. PMID: 36321670.
  37. 42Di H, et al. Thymosin beta 4: An emerging therapeutic candidate for kidney diseases. Peptides. 2026;195:171467. PMID: 41570941.
  38. 43Varghese S, et al. Rat thymosin beta 4 gene. Intron-containing gene and multiple retroposons. The Journal of biological chemistry. 1991;266(22):14256-61. PMID: 1650352.
  39. 44Kleinman HK, et al. Thymosin β4 Promotes Dermal Healing. Vitamins and hormones. 2016;102:251-75. PMID: 27450738.
  40. 45Li W, et al. In Vitro Study of Thymosin Beta 4 Promoting Transplanted Fat Survival by Regulating Adipose-Derived Stem Cells. Aesthetic plastic surgery. 2024;48(11):2179-2189. PMID: 38409346.
  41. 46Otero A, et al. Transcript levels of thymosin beta 4, an actin-sequestering peptide, in cell proliferation. Biochimica et biophysica acta. 1993;1176(1-2):59-63. PMID: 8452879.
  42. 47Shimamura R, et al. Expression of the thymosin beta 4 gene during differentiation of hematopoietic cells. Blood. 1990;76(5):977-84. PMID: 2393720.
  43. 48Kim J, et al. Thymosin beta-4 regulates activation of hepatic stellate cells via hedgehog signaling. Scientific reports. 2017;7(1):3815. PMID: 28630423.
  44. 49Rahaman KA, et al. Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro. Journal of chromatography. B, Analytical technologies in the biomedical and life sciences. 2024;1235:124033. PMID: 38382158.
  45. 50Ye C, et al. Therapeutic potential of thymosin beta 4 in a variety of diseases. Asian journal of surgery. 2024;47(11):4865. PMID: 38824027.
  46. 51Drum CL, et al. Thymosin Beta-4 Is Elevated in Women With Heart Failure With Preserved Ejection Fraction. Journal of the American Heart Association. 2017;6(6). PMID: 28611096.
  47. 52Choi J, et al. Thymosin Beta 4 Inhibits LPS and ATP-Induced Hepatic Stellate Cells via the Regulation of Multiple Signaling Pathways. International journal of molecular sciences. 2023;24(4). PMID: 36834849.
  48. 53Malinda KM, et al. Thymosin beta 4 stimulates directional migration of human umbilical vein endothelial cells. FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 1997;11(6):474-81. PMID: 9194528.
  49. 54Hannappel E, et al. Biosynthesis rates and content of thymosin beta 4 in cell lines. Archives of biochemistry and biophysics. 1985;240(1):236-41. PMID: 2990345.
  50. 55Yu FX, et al. Effects of thymosin beta 4 and thymosin beta 10 on actin structures in living cells. Cell motility and the cytoskeleton. 1994;27(1):13-25. PMID: 8194107.
  51. 56Zhu Z, et al. Thymosin beta 4 alleviates non-alcoholic fatty liver by inhibiting ferroptosis via up-regulation of GPX4. European journal of pharmacology. 2021;908:174351. PMID: 34280397.
  52. 57De La Cruz EM, et al. Thymosin-beta(4) changes the conformation and dynamics of actin monomers. Biophysical journal. 2000;78(5):2516-27. PMID: 10777749.
  53. 58Han HJ, et al. Thymosin beta 4-Induced Autophagy Increases Cholinergic Signaling in PrP (106-126)-Treated HT22 Cells. Neurotoxicity research. 2019;36(1):58-65. PMID: 30552633.
  54. 59Sanders MC, et al. Thymosin beta 4 (Fx peptide) is a potent regulator of actin polymerization in living cells. Proceedings of the National Academy of Sciences of the United States of America. 1992;89(10):4678-82. PMID: 1584803.
  55. 60Wang YY, et al. Thymosin Beta-4 Recombinant Adeno-associated Virus Enhances Human Nucleus Pulposus Cell Proliferation and Reduces Cell Apoptosis and Senescence. Chinese medical journal. 2015;128(11):1529-35. PMID: 26021512.
The TB-500 Report · $19

Everything you need to start.

Dose, sourcing, safety, our verdict. One purchase. Yours forever.

Built from 60 cited studies.

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