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documented protocols

Thymosin beta-4: what is documented about dosing

The trial doses are on the public record and they belong to specific formulations in specific conditions. What does not exist is an established amount for anything else.

Last Reviewed Editorial policy Methodology

This compound is unusual in that some real numbers exist, because registered trials published their dose arms. Those numbers are reported here as what a trial administered, which is the only thing they are.

Not medical advice

This page reports what has been documented about a compound. It is not medical advice, not a diagnosis, not a dosing protocol, and not a recommendation to obtain or use anything described here. Talk to a licensed clinician about anything concerning your health. Read the full disclaimer.

Reviewed against editorial standards Updated

What this page reports, and what it does not

We report what has been documented. We do not prescribe what should be done.

Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.

No trial established an amount of Thymosin beta-4 for a person. Most of the rows below record what a published study gave to its animals or its cells, in the model that study built, with the species and the route named on the line. One row records that other figures circulate in community write-ups, and that this site does not republish them. Nothing here is a protocol, nothing here is scaled for a person, and this site publishes no preparation steps, no administration technique and no equipment. The reasoning is in the editorial policy.

Commonly cited protocols (extrapolated, not validated)

What published studies gave, in which species and by which route, and what circulates elsewhere. The source class is named on every row, and none of it is a clinical protocol
StudyWhat was givenFrequencyDurationNotes
NCT05485818, Phase 2 cardiac0.25, 0.5 and 2.0 micrograms per kilogram as separate armsNot reported in the registry recordNot reported in the registry record62 participants, acute myocardial infarction, results not posted
NCT05984134, Phase 2 cardiac0.5 and 1.0 micrograms per kilogram against placeboNot reported in the registry recordNot reported in the registry record90 participants, acute myocardial infarction, results not posted
NCT04555850, Phase 1bSingle intravenous doses of 0.5, 2.0 and 5.0 micrograms per kilogramSingle doseSingle dose30 healthy volunteers, results not posted
RGN-259 Phase 3 programme0.1% ophthalmic solutionNot reported hereNot reported hereThe concentration used across the published and registered eye trials

Commonly cited protocols (extrapolated, not validated) for the injected research-chemical market are not derived from any of the figures above. They circulate for TB-500, which is a different and much smaller molecule, and the amounts discussed there are not related to the microgram-per-kilogram arms of the registered trials by any published conversion.

Three things prevent the trial numbers above from becoming a dose for anything else. They belong to a specific recombinant preparation rather than to a research chemical of unverified identity. They were selected for a single acute condition under monitoring in hospital, immediately after a cardiac procedure. And none of the trials that used them has posted a result, so it is not established that any of the arms did anything, or that one was better than another.

The ophthalmic concentration is on a firmer footing because it comes from a published trial, and it is a concentration in an eye drop rather than an amount given to a body.

Nothing here is a dosing recommendation. Statements about dosing reflect community and research reports only.

Our takeThe honest summary is short. Real doses exist for a recombinant drug in hospital trials for one acute condition, and none of those trials has reported a result. For every other use, no amount has been established, and the figures circulating for the market are attached to a different molecule.,Talk to a licensed clinician about anything concerning your health.

Main routes people compare

Intravenous

The route used in every registered trial of the injected recombinant preparation, both the healthy-volunteer studies and the cardiac studies. It is given in hospital, under monitoring, by people who are not the person receiving it.

Topical ophthalmic

The formulation with the strongest published evidence, and the one used across the whole Phase 3 programme. It is an eye drop, and its concentration is not an amount given to a body.

Subcutaneous

The route associated with the research-chemical market. No registered trial of this protein used it, so nothing on the public record describes what it does by this route.

What is said about cycle length and timing

Only one duration appears in the published record: the cardiac trial's first dose was given within a defined window after the procedure, and the mouse work used seven days of treatment. There is no published cycle length for anything else, and there is nothing to base one on.

Talk to a licensed clinician about anything concerning your health.

What has been measured about safety

A reader weighing what other people report giving usually wants the other half of the record next. What has been measured about Thymosin beta-4, and what has never been studied reports what has actually been measured, in what system and over what period, and the questions no published study has put.

Frequently asked questions

Are there real published doses for thymosin beta-4?

Yes, for a specific recombinant preparation in registered hospital trials: microgram-per-kilogram intravenous arms in cardiac and healthy-volunteer studies, and a 0.1% ophthalmic solution. None of the cardiac or volunteer trials has posted results, so it is not established what those arms achieved.

Do the TB-500 dosing figures apply to this protein?

No published conversion connects them. TB-500 is a seven amino acid fragment and this is a 43 amino acid protein, and the figures discussed for the fragment are not derived from the registered trials of the protein.

Why does this page not give an amount to use?

Because no amount has been established for any use outside those trials, and this site reports what has been documented rather than prescribing what should be done.

References

  1. Zhang Y, Dong Q, Bian X, Qiao Z, Cui C, Yang N, Liu J, Fu R, Zhang J, Jia L, Wu C, Guo J, Lin W, Wang J, Fan J, Li Y, Liu F, Yang B, Jia X, Gao C, Bai M, He Y, Han C, Yin D, Dou K. Recombinant human thymosin beta 4 improves ischemic cardiac dysfunction in mice and patients with acute ST-segment elevation myocardial infarction after reperfusion. Cardiovasc Res. 2025. PMID 41229390 DOI 10.1093/cvr/cvaf223
  2. Sosne G, Kleinman HK, Springs C, Gross RH, Sung J, Kang S. 0.1% RGN-259 (Thymosin ß4) Ophthalmic Solution Promotes Healing and Improves Comfort in Neurotrophic Keratopathy Patients in a Randomized, Placebo-Controlled, Double-Masked Phase III Clinical Trial. Int J Mol Sci. 2022. PMID 36613994 DOI 10.3390/ijms24010554
  3. Gonzalez-Franquesa A, Stocks B, Borg ML, Kuefner M, Dalbram E, Nielsen TS, Agrawal A, Pankratova S, Chibalin AV, Karlsson HKR, Gheibi S, Björnholm M, Jørgensen NR, Clemmensen C, Hostrup M, Treebak JT, Krook A, Zierath JR, Deshmukh AS. Discovery of thymosin β4 as a human exerkine and growth factor. Am J Physiol Cell Physiol. 2021. PMID 34495765 DOI 10.1152/ajpcell.00263.2021
  4. Gao X, Liang H, Hou F, Zhang Z, Nuo M, Guo X, Liu D. Thymosin Beta-4 Induces Mouse Hair Growth. PLoS One. 2015. PMID 26083021
  5. Tan WKY, Purnamawati K, Pakkiri LS, Tan SH, Yang X, Chan MY, Drum CL. Sources of variability in quantifying circulating thymosin beta-4: literature review and recommendations. Expert Opin Biol Ther. 2018. PMID 29502471 DOI 10.1080/14712598.2018.1448382
  6. Pipes GT, Yang J. Cardioprotection by Thymosin Beta 4. Vitam Horm. 2016. PMID 27450736 DOI 10.1016/bs.vh.2016.04.004
  7. Hoch K, Volk DE. Structures of Thymosin Proteins. Vitam Horm. 2016. PMID 27450728 DOI 10.1016/bs.vh.2016.04.009
  8. Hannappel E. Thymosin beta4 and its posttranslational modifications. Ann N Y Acad Sci. 2010. PMID 20536447 DOI 10.1111/j.1749-6632.2010.05485.x
  9. 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. PMID 22074294 DOI 10.1517/14712598.2012.634793
  10. Sosne G. Thymosin beta 4 and the eye: the journey from bench to bedside. Expert Opin Biol Ther. 2018. PMID 30063853 DOI 10.1080/14712598.2018.1486818 PubMed types this as a Personal Narrative, and the author is also first author on the ReGenTree-funded Phase 3 cited above. Used here for programme history only.
  11. ReGenTree, LLC. Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-3. Phase 3, 700 participants actual, completed October 2021. Read through the ClinicalTrials.gov API on 23 August 2026: the record carries no results section. ClinicalTrials.gov. 2019. NCT03937882
  12. ReGenTree, LLC. Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-2. Phase 2/3, completed. ClinicalTrials.gov. 2016. NCT02974907
  13. ReGenTree, LLC. Assessment of the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution. Phase 3, recruiting as of 23 August 2026. ClinicalTrials.gov. 2022. NCT05555589
  14. RegeneRx Biopharmaceuticals. A Phase 1 Safety Study of the Intravenous Administration of Thymosin Beta 4. Withdrawn before enrolling any participant. ClinicalTrials.gov. 2009. NCT00743769
  15. RegeneRx Biopharmaceuticals. A Study of the Safety and Efficacy of Injectable Thymosin Beta 4. Phase 2, withdrawn before enrolling any participant. ClinicalTrials.gov. 2011. NCT01311518
  16. RegeneRx Biopharmaceuticals. Study of Thymosin Beta 4 in Patients With Pressure Ulcers. Phase 2, completed, no posted results. ClinicalTrials.gov. 2006. NCT00382174
  17. RegeneRx Biopharmaceuticals. Study of Thymosin Beta 4 in Patients With Venous Stasis Ulcers. Phase 2, completed, no posted results. ClinicalTrials.gov. 2009. NCT00832091
  18. RegeneRx Biopharmaceuticals. A Phase 2 Study on Effect of Thymosin Beta 4 on Wound Healing. Terminated. ClinicalTrials.gov. 2006. NCT00311766
  19. Beijing Northland Biotech. Co., Ltd. Safety and Efficacy Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction. Phase 2, 62 participants actual, completed, no posted results. Dose arms of 0.25, 0.5 and 2.0 micrograms per kilogram. ClinicalTrials.gov. 2022. NCT05485818
  20. Beijing Northland Biotech. Co., Ltd. Efficacy and Safety Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction. Phase 2, 90 participants actual, completed, no posted results. Dose arms of 0.5 and 1.0 micrograms per kilogram against placebo. ClinicalTrials.gov. 2023. NCT05984134
  21. Beijing Northland Biotech. Co., Ltd. A Phase 1b Study of Thymosin Beta 4 in Healthy Volunteers. 30 volunteers, completed, no posted results. Single intravenous doses of 0.5, 2.0 and 5.0 micrograms per kilogram. ClinicalTrials.gov. 2020. NCT04555850
  22. Beijing Northland Biotech. Co., Ltd. A Phase 1a Study of Thymosin Beta 4 in Healthy Volunteers. Completed, no posted results. ClinicalTrials.gov. 2020. NCT04555824
  23. Beijing Northland Biotech. Co., Ltd. Recombinant Human Thymosin Beta 4 for Injection (NL005) for Acute Myocardial Infarction. Phase 2c, 189 participants estimated, not yet recruiting as of 23 August 2026. Primary outcome is infarct size on cardiac magnetic resonance at 90 days. ClinicalTrials.gov. 2026. NCT07586865
  24. ReGenTree, LLC. Safety and Efficacy of Thymosin Beta 4 Ophthalmic Solution in Patients With Dry Eye. Phase 2, completed. ClinicalTrials.gov. 2011. NCT01387347
  25. Michigan Cornea Consultants. Comparative Study of Thymosin Beta 4 Eye Drops vs. Vehicle. Phase 2, completed. ClinicalTrials.gov. 2011. NCT01393132
  26. ReGenTree, LLC. A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4. Terminated. ClinicalTrials.gov. 2008. NCT00598871
  27. ReGenTree, LLC. Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome. Phase 2/3, completed. ClinicalTrials.gov. 2015. NCT02597803
  28. Hudson Biotech. TB-500 (Thymosin Beta 4 17-23 Fragment) in Adults With Stable Atherosclerotic Cardiovascular Disease. Read through the ClinicalTrials.gov API on 23 August 2026: the registered brief summary opens by stating that it is a fictional study and an example of a ClinicalTrials.gov-style record. It is the only registration naming TB-500. ClinicalTrials.gov. 2026. NCT07487363
  29. ReGenTree, LLC. Assessment of the Safety and Efficacy Study of RGN-259 Ophthalmic Solutions for Neurotrophic Keratopathy: SEER-1. Phase 3, terminated, 18 participants actual against 46 planned. This is the registration for the published trial cited above, and it is filed under the drug name RGN-259, which is why a search on the molecule name does not return it. ClinicalTrials.gov. 2015. NCT02600429
  30. World Anti-Doping Agency. The 2026 Prohibited List. Read in full on 23 August 2026. Section S2.3, Growth Factors and Growth Factor Modulators, names Thymosin-ß4 and its derivatives e.g. TB-500. The S2 class heading states that the class is prohibited at all times, in and out of competition, and that all substances in it are non-Specified. World Anti-Doping Agency. 2026. WADA 2026 Prohibited List