Thymosin Beta-4 dosage and evidence

What is Thymosin Beta-4?

How does Thymosin Beta-4 work?

It grabs actin, a protein that shapes the cell's inner frame. That helps cells move, helps new blood vessels grow and calms swelling where there is an injury.

What have studies in people found about Thymosin Beta-4?

Thymosin beta 4's real record in people is eye drops, and they mostly failed. Two large final-stage dry eye trials, of 601 and 700 patients, found the drops did no better than a dummy solution. No published study tests the injected peptide for an injury. The TB-500 fragment sold as a healing peptide has no finished human trial at all.

• Dry eye, 700 people (NCT03937882): they used the drops or a dummy solution. At day 15, eye surface damage and eye discomfort had improved by the same amount in both groups.
• Dry eye, 601 people (NCT02974907): they used 0.1% drops or a dummy solution. At day 29, eye discomfort and surface damage were no better on the drug. On discomfort the drug group was very slightly worse.
• Dry eye, 72 people: they used the drops or a dummy solution for 28 days. Neither main measure differed at day 29. On extra measures, discomfort in a room with deliberately dried air was 27% lower on the drug, and damage on parts of the eye surface improved.
• Cornea wounds that would not heal: 6 of 10 people on the drops healed fully at 4 weeks, against 1 of 8 on the dummy solution. That gap was too small to rule out chance. One eye damage score improved at day 43, and no serious side effects were seen. The trial (NCT02600429) was stopped after 18 people for what the registry calls a business decision.
• Severe dry eye (already cited on this page): 9 patients had 35% less discomfort and 59% less surface damage than on the dummy solution at day 56.
• A third large dry eye trial, 317 people (NCT02597803), finished in July 2016 and has never posted results.
• Doses into a vein exist only as early studies with no results posted. In China, 54 healthy volunteers got single rising doses (finished June 2018), and 30 got repeated doses (finished July 2019). A 62-patient heart attack study finished in November 2021 and a 90-patient follow-up in May 2023. None has posted results.
• TB-500, the short fragment actually sold under that name, entered its first registered human trial in February 2026 (NCT07487363). It is an early dose study in 80 adults with stable heart artery disease, due to finish in February 2028.

What this does not tell you: Every good result here comes from a drop placed on an eye. How well an eye drop is tolerated says nothing about the safety of repeated shots under the skin. And dry eye and cornea results have nothing to do with tendon, muscle or ligament repair, which is what the injection market sells. The cornea healing result comes from 18 people in a trial stopped early, and it could not rule out chance. TB-500 is not thymosin beta 4. It is a short piece of it, and no finished trial has given it to a person. The skin wound trials summed up in the 2012 review on this page found faster healing only among patients who healed. That is not the same as more patients healing.

What do people who took Thymosin Beta-4 report?

This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.

• The first thing to understand about this discussion is that forums do not separate full-length thymosin beta-4 from the shorter TB-500 fragment sold under that name. The two are used interchangeably in almost every thread, so no self-report in this material can be read as being about the full-length peptide specifically.
• Described use is a shot under the skin, usually into the belly. The repeated reasoning offered is that injecting near the injury is not needed, because the peptide is assumed to act through the whole body. That assumption is stated as settled in these threads rather than argued for.
• Dose patterns described include vials split into roughly 3 mg portions given a few times a week, figures in the range of several milligrams weekly, and much smaller daily amounts in the hundreds of micrograms. The schedules come from board convention, and different posters describe very different amounts without much reconciliation.
• Where people report improvement it is for a joint or tendon problem, described as beginning within the first few injections and as clearer after about a week, and it is almost always described alongside BPC-157 rather than on its own, which makes attribution impossible.
• Negative reports exist and take a specific form: people who ran a course and got nothing, who then attribute it to the vial rather than the compound, in one case describing what they believed was inert liquid from a previous supplier. Counterfeit and mislabelled product is the standing explanation offered for failure, which is worth noticing as a pattern rather than accepting as an answer.
• Cost is raised concretely, with figures in the low hundreds of dollars for a short course, and vendor recommendations circulate freely. Side effect discussion is thin beyond headache, nausea and fatigue being listed as possibilities, and a separate long-running thread exists purely about whether a compound that promotes tissue growth could promote tumour growth, which remains unresolved in the discussion itself.

Sources: Peptide and injury threads on ExcelMale, plus a long-running safety thread on LongeCity, found by site-restricted search and read in September 2026. Nothing above is attributed to any specific post and no post is reproduced.

The state of the research

The evidence, in charts

The studies we cite

• Study in people2015
  Thymosin beta 4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial

  Eye drops helped severe dry eye in a study of nine people, which is far too few to rely on. Patients used either the thymosin beta 4 drops or drops without it, and nobody involved knew which. After eight weeks, discomfort was down 35% and damage to the surface of the eye down 59% compared with the plain drops. Nine patients is a handful. These are drops on the eye, not an injection, so they say nothing about the injectable peptide sold online.

  Small placebo-controlled Phase 2 (9 patients): RGN-259 eye drops cut ocular discomfort 35% and corneal staining 59% versus vehicle at day 56.

  PMID 25826322 Cornea
• Study in people2012
  The regenerative peptide thymosin beta 4 accelerates the rate of dermal healing in preclinical animal models and in patients

  In two mid stage trials, thymosin beta 4 closed stubborn skin ulcers faster in the people whose ulcers closed at all. The gain was close to a month of healing time. The rest of this paper is animal work, which tells you nothing reliable about people. The human result is limited in an important way. It counts only the patients who healed, so it cannot tell you whether more people healed overall. These were wounds treated on the skin.

  Summarizes animal wound models and two Phase 2 trials in venous stasis and pressure ulcers where Tbeta4 sped healing by almost a month in patients who healed.

  PMID 23050815 Annals of the New York Academy of Sciences
• Study in people2018
  Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome : ARISE-2

  A large trial of thymosin beta 4 eye drops found nothing. It gave 601 people with dry eye either the drops or an identical dummy solution. A month in, eye discomfort and the staining that shows surface damage were no better on the drug. On discomfort the drug group was fractionally worse. This is one of the two biggest tests this peptide has ever been given, and it came out flat.

  601 patients, 0.1% RGN-259 against placebo. Registry-posted primary results at day 29: ocular discomfort plus 0.07 versus minus 0.04, corneal fluorescein staining plus 0.07 versus minus 0.01, on scales where higher is worse.

  NCT02974907 ClinicalTrials.gov, ReGenTree, LLC
• Study in people2021
  Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-3

  The biggest trial of these eye drops came out flat as well. Seven hundred people with dry eye used the drops or a dummy solution, and after two weeks both groups had improved by the same amount. Everybody getting better together is what you see when the improvement is not coming from the drug. A trial this size would have shown a real difference if one existed.

  700 patients. Registry-posted primary results at day 15: inferior corneal staining minus 0.41 on drug against minus 0.46 on placebo, ocular discomfort minus 0.4 on both arms. The two groups moved together.

  NCT03937882 ClinicalTrials.gov, ReGenTree, LLC
• Study in people2016
  Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-1

  This trial finished ten years ago and has never said what it found. It assigned 317 people with dry eye in the first of three large tests of these drops, and it closed in July 2016. Nothing has been posted to the public registry since. A completed trial that reports nothing is itself a finding. Its two sister trials did report, and both came out flat.

  317 patients randomized in the first of the three Phase 3 dry eye trials, completed July 2016. No results have been posted to the registry.

  NCT02597803 ClinicalTrials.gov, ReGenTree, LLC
• Study in people2015
  Thymosin beta 4 ophthalmic solution for dry eye: a randomized, placebo-controlled, Phase II clinical trial conducted using the controlled adverse environment (CAE) model

  The main measures in this small trial came out even. Seventy two people with dry eye used the drops or a dummy solution for four weeks, and neither of the two things the trial was built to measure separated. In a chamber where the air was dried out deliberately, the drug group reported less discomfort, and staining in parts of the cornea improved. Those were extra measures, not the test the trial had set itself.

  72 subjects randomized 1:1 for 28 days: neither primary endpoint separated from placebo. Secondary endpoints showed 27% lower discomfort during the chamber challenge (p = 0.0244) and improved central and superior corneal staining.

  PMID 26056426 Clinical Ophthalmology
• Study in people2022
  0.1% RGN-259 (Thymosin beta 4) Ophthalmic Solution Promotes Healing and Improves Comfort in Neurotrophic Keratopathy Patients in a Randomized, Placebo-Controlled, Double-Masked Phase III Clinical Trial

  The most encouraging human result for this peptide comes from eighteen people. Adults with a cornea wound that would not close used the drops or a dummy solution. Six of ten healed fully on the drug against one of eight on the dummy. Eighteen people is too few to separate that gap from chance, and the authors say so. The trial was stopped early, not for safety, but because the sponsor made a business decision.

  Complete healing at 4 weeks in 6 of 10 treated subjects against 1 of 8 on placebo, which did not reach significance (p = 0.0656). The parent trial, SEER-1, was terminated after 18 subjects for a business decision.

  PMID 36613994 International Journal of Molecular Sciences
• Study in people2026
  TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD

  Nobody has yet finished testing TB-500 in people. The fragment sold under that name entered its first registered human trial in February 2026, an early safety and dose study in 80 adults with stable heart artery disease. It is expected to finish in February 2028. Until then, every claim made for the injectable healing peptide rests on animal work and on trials of a different, longer molecule.

  The first registered human trial of the fragment sold as TB-500: a Phase 1/2 randomized, double-blind, placebo-controlled dose escalation in 80 adults with stable atherosclerotic cardiovascular disease, recruiting since February 2026 with estimated completion in February 2028.

  NCT07487363 ClinicalTrials.gov, Hudson Biotech
• Review of studies2005
  Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues

  A review of how thymosin beta-4 holds loose actin inside cells. It covers its roles in healing skin and eye wounds, and in repair after blood flow is cut off.

  Reviews Tbeta4 as the major G-actin sequestering peptide and its roles in dermal and corneal wound healing and post-ischemic repair.

  PMID 16099219 Trends in Molecular Medicine
• Animal study2004
  Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair

  In mice after a blocked heart artery, thymosin beta-4 helped heart muscle cells survive and the heart work better.

  After coronary ligation in mice, Tbeta4 activated ILK/Akt, improved early cardiomyocyte survival and cardiac function.

  PMID 15565145 Nature