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Thymosin beta-4 · Dose evidence · updated 8 October 2026

Thymosin beta-4 dosage: what studies actually used

The short answer

Human trials of thymosin beta-4 used eye drops, mostly at 0.1%, wound gels of 0.01% to 0.1%, and IV doses: 42 to 1,260 mg in a US safety study, and 0.05 to 25 µg/kg of a recombinant version in China891011. No product containing it is approved, so no dose is established for any use, and we found no registered trial that tested it on muscle, tendon or ligament injuries or gave it by injection under the skin or into muscle1213. These are doses of the full 43-amino-acid protein, not of TB-500, its 7-amino-acid fragment14. This page reports those doses and is not dosing advice.

Not dosing advice. This page reports doses that studies and approved labels used, with their sources. It does not recommend a dose, and we do not give mixing, injection or unit-conversion instructions. Gray-market vials often do not contain what their label says. How we report doses.

Every dose studied in people

StudyWhoPeopleDose and routeWhat happened
ARISE-3 (NCT03937882), randomized Phase 3 trial Adults with dry eye 700 0.1% RGN-259 drops in both eyes four times a day, or placebo drops
Eye drops · 14 days		 Results posted on 28 August 2026 show the main staining score down 0.41 points on the drops and 0.46 on placebo at day 15, and discomfort down 0.4 in both groups, with no statistical test8. The company said the trial did not meet its primary outcome measures, and no serious adverse events occurred in either group815.
ARISE-2 (NCT02974907), randomized Phase 3 trial Adults with dry eye 601 0.1% RGN-259 drops four times a day, or placebo drops
Eye drops · 28 days		 At day 29, discomfort was up 0.07 points on the drops and down 0.04 on placebo, on a 0-to-5 scale, with no statistical test posted16. The company reported a significant drop in discomfort at day 15 (p = 0.0149) but said the trial did not duplicate ARISE-1’s results; serious adverse events affected 3 of 299 people on the drops and 2 of 302 on placebo1617.
ARISE-1 (NCT02597803), randomized Phase 2/3 trial Adults with dry eye 317 0.05% or 0.1% RGN-259 drops four times a day, or placebo drops
Eye drops · 28 days		 The company said the primary outcome measures were not met, but that several key related pre-specified measures, and subgroups with more severe dry eye, showed statistically significant treatment effects1. It reported no significant drug-related adverse events, and no results have been posted to the registry12.
Zhang 2025, randomized placebo-controlled trial (published with mouse studies) Patients with an ST-elevation heart attack, after a procedure to reopen the artery 96 Recombinant thymosin beta-4; the abstract gives no amount
Not stated in the abstract · Follow-up to 90 days; dosing length not stated in the abstract		 Across all 96 patients, the infarcted (damaged) area did not differ significantly from placebo; it was significantly smaller at 90 days in the group whose first dose came within 8 hours of the procedure (n = 43 in the abstract)18. The abstract names no trial registration18.
NL005 Phase 2b (NCT05984134), randomized placebo-controlled trial Adults aged 18 to 75 in Beijing with a heart attack, after a procedure to reopen the artery 90 0.5 µg/kg, or a higher dose the record gives as 1.0 µg/kg in one place and 1.5 µg/kg in another, 12 hours after the procedure, then on days 2 to 7; or placebo
IV · 7 days, with measurements to day 90		 Completed in May 2023; the record, last updated on 21 June 2024, has no posted results19.
Leg-ulcer trial (NCT00832091; Guarnera 2010), Phase 2 dose-escalation trial Adults aged 18 to 79 with venous leg ulcers, in Italy and Poland 73 0.01%, 0.03% or 0.1% gel once a day, or placebo gel
Gel on the ulcer · Up to 84 days		 Safety, the main measure, was judged ‘comparable to placebo’20. By day 84, ulcers had closed in 12 of 55 people on the gel and 4 of 17 on placebo; the registry lists 72 participants, the paper 73920.
Pressure-ulcer trial (NCT00382174), Phase 2 dose-response trial Adults aged 18 to 85 with pressure ulcers, at US sites 72 0.01%, 0.02% or 0.1% gel once a day, or placebo gel
Gel on the ulcer · Up to 84 days		 Safety was the main measure; by day 84, ulcers had healed in 8 of 54 people on the gel and 3 of 18 on placebo21.
Dry-eye chamber trial (NCT01387347; Sosne 2015), Phase 2 Adults with moderate to severe dry eye, tested in a room set up to worsen dry-eye symptoms 72 0.1% eye drops twice a day, or placebo drops
Eye drops · 28 days		 Neither main measure differed significantly from placebo at day 29, though discomfort in the test room on day 28 was 27% lower than on placebo (P = 0.0244), a secondary measure; no adverse events were observed22.
Yu 2021, randomized trial against ketoconazole and placebo People with seborrheic dermatitis of the scalp: 25 given the gel, 21 ketoconazole lotion and 25 placebo 71 0.5 mg ml-1 recombinant thymosin beta-4 gel, with the study products used every other day
Gel on the scalp · 4 weeks, with follow-up to day 168		 The authors concluded that the gel worked significantly better than 2% ketoconazole lotion and that its effect was sustained after treatment stopped3.
NL005 Phase 2a (NCT05485818), randomized placebo-controlled trial Adults aged 18 to 75 in Beijing with a heart attack, after a procedure to reopen the artery 62 0.25, 0.5 or 2.0 µg/kg 12 ± 4 hours after the procedure, then on days 2 to 7; or placebo
IV · 7 days, with measurements to day 90		 Completed in November 2021; the record, last updated on 3 August 2022, has no posted results23.
NL005 Phase 1a (Wang 2021), single rising doses Healthy volunteers aged 18 to 50 in China 54 One dose of 0.05, 0.25, 0.5, 2, 5, 12.5 or 25 µg/kg, or placebo
IV · Single dose		 No serious adverse events or dose-limiting toxicities; adverse events, all mild or moderate, occurred in 25 of 44 people on NL005 and 7 of 10 on placebo11.
Ruff 2010, randomized placebo-controlled safety study Healthy volunteers, in four groups of 10 40 42, 140, 420 or 1,260 mg (one level per group), or placebo
IV · One dose, then daily for 14 days		 No dose-limiting toxicity or serious adverse event at any level, and the authors called the whole range well tolerated10.
NL005 Phase 1b (Wang 2021), rising daily doses Healthy volunteers aged 18 to 50 in China 30 0.5, 2 or 5 µg/kg once a day, or placebo
IV · 10 days		 No serious adverse events or dose-limiting toxicities; adverse events occurred in 16 of 24 people on NL005 and 5 of 6 on placebo, and the drug showed no obvious build-up over the 10 days11.
Epidermolysis bullosa trial (NCT00311766), Phase 2, stopped early People aged 2 and older with epidermolysis bullosa, a group of mostly inherited blistering skin diseases 30 0.01%, 0.03% or 0.1% gel once a day, or placebo gel
Gel on wounds · Up to 56 days		 Stopped for lack of patients and because the study drug expired; wounds healed in 8 of 22 people on the gel and 5 of 8 on placebo, a difference that was not statistically significant24.
SEER-1 (NCT02600429; Sosne 2022), Phase 3, stopped early Adults with neurotrophic keratopathy (stages 2 and 3), a nerve-damage disease of the cornea 18 0.1% RGN-259 drops five times a day, or placebo drops
Eye drops · 4 weeks, with follow-up to day 43		 The defect healed completely after 4 weeks, the main measure, in 6 of 10 people on the drops and 1 of 8 on placebo (p = 0.0656)25. Complete healing was recorded in 4 of 10 on the drops at day 36 and 5 of 10 at day 43, two weeks after treatment ended, against 1 and 0 of 8 on placebo; the day-43 difference was significant (p = 0.0359)2526. The trial was stopped for a business decision26.
Lee 2021, chart review with no control group Knee-pain patients at one Florida clinic; 4 of those reached were also given ‘TB4’ 17 No amount given for TB4; BPC-157 at 2 to 4 mg, once or twice
Injection into the knee joint, combined with BPC-157 · Phone follow-up mostly 6 months to 1 year later		 Of the 4 given both peptides, the authors report 75% with significant improvement and 25% with no relief27. FDA’s review calls the injection a compounded combination of thymosin-beta-4 (TB4) and BPC-157 and gives amounts for the BPC-157 only28.
Corneal-wound trial (NCT00598871), Phase 2, stopped early Adults with diabetes whose corneal surface was removed during eye surgery (vitrectomy) 12 0.01% eye drops, 2 drops four times a day, or placebo drops
Eye drops · 14 days, with a check at day 28		 Stopped for slow recruitment; by day 14 the wound had closed in all 9 people on the drops and all 3 on placebo, and every participant, on the drops or on placebo, had at least one adverse event in the treated eye, none of them serious4.
Severe dry-eye trial (NCT01393132; Sosne 2015), Phase 2 Adults with severe dry eye, including dry eye from graft-versus-host disease 9 0.1% eye drops six times a day, or vehicle drops
Eye drops · 28 days, with follow-up to day 56		 At day 56, the 12 treated eyes had 35.1% less discomfort and 59.1% less corneal staining than the 6 eyes given vehicle drops29.
Dunn 2010, compassionate-use case series People aged 37 to 84 with long-standing corneal wounds that would not heal (neurotrophic defects) 9 Thymosin beta-4 eye drops; the abstract gives no strength or frequency
Eye drops · 28 or 49 days, then 30 days of follow-up		 The authors reported dramatic healing in the 6 patients with map-shaped (‘geographic’) defects and no demonstrable change in the 3 with pinpoint (‘punctate’) defects; there was no comparison group5.
CELEB (NCT03578029), Phase 2, stopped early People aged 4 and older with junctional or dystrophic epidermolysis bullosa 4 RGN-137 gel once a day, or placebo gel; the record gives no strength
Gel on wounds · Up to 84 days		 Ended after 4 patients for a ‘Business Decision’, and no results have been posted30.
SEER-2 (NCT05555589), randomized Phase 3 trial, results pending Adults with neurotrophic keratopathy, at 41 US and 9 European hospitals – 0.1% RGN-259 drops five times a day, or placebo drops
Eye drops · 28 days		 In an announcement RegeneRx reproduced on 1 September 2026, its partner HLB Therapeutics said treatment and follow-up were complete and that the contract research organization managing the trial had proposed mid-November as the target for submitting top-line results31. The registry record, last updated on 23 December 2025, still said recruiting and estimated 70 participants6.

Studies, animals and users: kept apart

Doses below are what studies used or what a label says. They are not advice, and gray-market products may not contain what their label says.

In human studies

Eye drops: 0.1% four times a day for 14 days (ARISE-3) or 28 days (ARISE-2), five times a day for 4 weeks (SEER-1), twice a day for 28 days (a dry-eye chamber trial) and six times a day for 28 days (severe dry eye)816262932. Skin gels: 0.01%, 0.03% or 0.1% once a day for up to 84 days (leg ulcers) or up to 56 days (epidermolysis bullosa), and 0.01%, 0.02% or 0.1% for up to 84 days (pressure ulcers)92124. IV: 42, 140, 420 or 1,260 mg once and then daily for 14 days in healthy volunteers10; the recombinant NL005 at 0.05 to 25.0 µg/kg once, or 0.5, 2.0 or 5.0 µg/kg daily for 10 days, in healthy volunteers11, and at 0.25 to 2.0 µg/kg daily for 7 days in heart-attack patients1923. None of these doses applies to TB-500, a different molecule14.

In animal studies

Mice (skin wounds): 50 µL of 0.1% thymosin beta-4 in buffered saline or 0.05% in a hydrogel on each wound, on the day of wounding and 48 hours later, in 26-month-old mice, as described in FDA’s review14. Rats (knee ligament): 1 µg in 100 µL of fibrin sealant placed in the gap of the cut ligament at surgery33.

What users report

No community dosing page was cited for this compound.

Half-life and how it is taken

Half-life
0.5 to 2.08 hours after an IV dose (recombinant version, healthy volunteers)11In the Chinese trial of NL005, blood levels peaked 3 to 15 minutes after an IV dose, and the authors say the half-life matched reports on chemically made thymosin beta-411. In the earlier US trial of much larger IV doses, the half-life grew longer as the dose rose10. We found no registered trial that measured it after injection under the skin or into muscle12.
Routes
  • Eye drops (human trials in dry eye and corneal disease)
  • Gel on skin wounds (human trials in ulcers and epidermolysis bullosa)
  • IV injection (healthy volunteers and heart-attack trials)
  • Knee-joint injection with BPC-157 (4 patients in one chart review)
  • Injection under the skin or into muscle (no human data found)

Which molecule these doses are for

These are doses of thymosin beta-4 itself: the leg-ulcer gel and the US IV study used a synthetic copy of the 43-amino-acid protein, and the Chinese trials used versions made by genetic engineering10111820. One of those, NL005, is 44 amino acids long according to its trial report11.

What a vial labeled thymosin beta-4 holds is a separate question. Sellers use the two names loosely: one product page pairs the name ‘TB-500 (Thymosin Beta 4)’ with the full protein’s formula, and the lab results Finnrick publishes include TB-500 but not thymosin beta-4143435. A dose printed on such a vial cannot be matched to the trial doses above. The 2021 knee-pain chart review is open to the same doubt, since its abstract identifies the compounded ‘TB4’ only by name2728.

Percentages, milligrams and micrograms per kilogram

The trials used three kinds of dose. Eye drops and wound gels were dosed by strength (a percentage) and by how many times a day they were applied; the US IV study by a fixed amount in milligrams; and the Chinese IV trials by body weight, in micrograms per kilogram49101132. The scalp-gel study gave its strength as 0.5 mg ml-13. A strength is not an amount, and an amount per kilogram is not a fixed amount, so this page gives every dose in its study’s own units and does not convert between them.

Within one unit, doses can be compared: a third Chinese heart-attack trial, planned for 189 patients, would give 10 or 20 µg/kg a day for 7 days, higher than the 0.25 to 2.0 µg/kg doses given in the two completed ones. Its record, last updated on 14 May 2026, said it was not yet recruiting71923.

Why no dose exists for injuries

None of the doses above was tested on muscle, tendon or ligament injuries: ClinicalTrials.gov and PubMed searches on 8 October 2026 found no trial in those injuries, and the only human report near that use that we found, a knee-pain chart review, gave no amount of thymosin beta-412272836.

No approved product has a label that could set a dose. FDA’s January 2026 warning letter to a registered compounding outsourcing facility called the thymosin beta-4 it made an unapproved new drug and a biological product with no approved biologics license1337.

Questions people ask

How much thymosin beta-4 should I take?

No dose has been established, because no product containing it is approved and we found no trial of it in muscle, tendon or ligament injuries121336. The trials used eye drops of 0.01% to 0.1%, wound gels and IV doses, in people with eye, skin or heart conditions and in healthy volunteers48102123. US pharmacies may not compound thymosin beta-4373839.

Has thymosin beta-4 been injected in people?

Yes, into a vein: trials gave it by IV to healthy volunteers in the US and China and to heart-attack patients in China10111923. We found no registered trial that injected it under the skin or into muscle; outside trials, one chart review describes knee-joint injections in 4 patients who were also given BPC-1571227.

What is the highest dose of thymosin beta-4 tested in people?

It depends on the unit, and this page does not convert between units: the US IV study went up to 1,260 mg a day for 14 days, the Chinese studies up to 25 µg/kg of a recombinant version given once, and the eye drops and wound gels up to 0.1%891011. Neither IV safety study found a dose-limiting toxicity at any level1011.

How long were people given thymosin beta-4 in studies?

The longest courses were gels applied once a day for up to 84 days to leg ulcers, pressure ulcers or blistering-skin wounds92130. Eye-drop courses ran 14 to 28 days, or up to 49 days in one compassionate-use series, and daily IV courses, where reported, ran 7 to 14 days5810111623.

Go deeper

Sources

  1. 1RGN-259 Confirms Efficacy in Signs and Symptoms of Dry Eye RegeneRx Biopharmaceuticals, 6 May 2016. regenerx.com
  2. 2Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-1 (NCT02597803) ClinicalTrials.gov, 17 Oct 2019. clinicaltrials.gov
  3. 3Recombinant human thymosin beta-4 (rhTβ4) improved scalp condition and microbiome homeostasis in seborrheic dermatitis Microbial Biotechnology, Sep 2021. pmc.ncbi.nlm.nih.gov
  4. 4A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 for Treating Corneal Wounds (NCT00598871) ClinicalTrials.gov, 8 Jul 2015. clinicaltrials.gov
  5. 5Treatment of chronic nonhealing neurotrophic corneal epithelial defects with thymosin beta4 Annals of the New York Academy of Sciences, Apr 2010. pubmed.ncbi.nlm.nih.gov
  6. 6Assessment of the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of NK: SEER-2 (NCT05555589) ClinicalTrials.gov, 23 Dec 2025. clinicaltrials.gov
  7. 7Recombinant Human Thymosin Beta 4 for Injection(NL005) for Acute Myocardial Infarction (NCT07586865) ClinicalTrials.gov, 14 May 2026. clinicaltrials.gov
  8. 8Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-3, NCT03937882 ClinicalTrials.gov, 28 Aug 2026. clinicaltrials.gov
  9. 9Study of Thymosin Beta 4 in Patients With Venous Stasis Ulcers (NCT00832091) ClinicalTrials.gov, 30 Mar 2010. clinicaltrials.gov
  10. 10A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers Annals of the New York Academy of Sciences, Apr 2010. pubmed.ncbi.nlm.nih.gov
  11. 11A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin β4 in healthy Chinese volunteers Journal of Cellular and Molecular Medicine, Sep 2021. pmc.ncbi.nlm.nih.gov
  12. 12ClinicalTrials.gov search: thymosin beta 4, timbetasin, Tb4, RGN-259, RGN-137, RGN-352 or NL005 (30 records; 20 test thymosin beta-4, none in muscle, tendon or ligament injuries) ClinicalTrials.gov, accessed 8 Oct 2026. clinicaltrials.gov
  13. 13Drugs@FDA via openFDA: search for active ingredient thymosin or timbetasin (no matches) U.S. Food and Drug Administration (openFDA), 8 Oct 2026. api.fda.gov · data query
  14. 14FDA Briefing Document, Pharmacy Compounding Advisory Committee meeting of July 23-24, 2026: TB-500-related bulk drug substances U.S. Food and Drug Administration, 15 May 2026. fda.gov
  15. 15RegeneRx Reports Topline Results of ARISE-3 Dry Eye Trial RegeneRx Biopharmaceuticals (PR Newswire), 18 Mar 2021. prnewswire.com
  16. 16Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye Syndrome: ARISE-2 (NCT02974907) ClinicalTrials.gov, 5 Jan 2022. clinicaltrials.gov
  17. 17RegeneRx JV Announces Results of ARISE-2 Dry Eye Trial RegeneRx Biopharmaceuticals, 31 Oct 2017. regenerx.com
  18. 18Recombinant human thymosin beta 4 improves ischemic cardiac dysfunction in mice and patients with acute ST-segment elevation myocardial infarction after reperfusion Cardiovascular Research, 31 Dec 2025. pubmed.ncbi.nlm.nih.gov
  19. 19Efficacy and Safety Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction (NCT05984134) ClinicalTrials.gov, 21 Jun 2024. clinicaltrials.gov
  20. 20The effect of thymosin treatment of venous ulcers Annals of the New York Academy of Sciences, Apr 2010. pubmed.ncbi.nlm.nih.gov
  21. 21Study of Thymosin Beta 4 in Patients With Pressure Ulcers (NCT00382174) ClinicalTrials.gov, 1 Feb 2010. clinicaltrials.gov
  22. 22Thymosin beta 4 ophthalmic solution for dry eye: a randomized, placebo-controlled, Phase II clinical trial conducted using the controlled adverse environment (CAE™) model Clinical Ophthalmology, 2015. pubmed.ncbi.nlm.nih.gov
  23. 23Safety and Efficacy Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction (NCT05485818) ClinicalTrials.gov, 3 Aug 2022. clinicaltrials.gov
  24. 24A Phase 2 Study on Effect of Thymosin Beta 4 on Wound Healing in Patients With Epidermolysis Bullosa (NCT00311766) ClinicalTrials.gov, 12 May 2014. clinicaltrials.gov
  25. 250.1% 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 International Journal of Molecular Sciences, 29 Dec 2022. pubmed.ncbi.nlm.nih.gov
  26. 26Assessment of the Safety and Efficacy Study of RGN-259 Ophthalmic Solutions for Neurotrophic Keratopathy: SEER-1 (NCT02600429) ClinicalTrials.gov, 30 Aug 2023. clinicaltrials.gov
  27. 27Intra-Articular Injection of BPC 157 for Multiple Types of Knee Pain Alternative Therapies in Health and Medicine, Jul 2021. pubmed.ncbi.nlm.nih.gov
  28. 28FDA Briefing Document, Pharmacy Compounding Advisory Committee meeting of July 23-24, 2026: BPC-157-related bulk drug substances U.S. Food and Drug Administration, 11 May 2026. fda.gov
  29. 29Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial Cornea, May 2015. pubmed.ncbi.nlm.nih.gov
  30. 30Evaluation of the Safety and Efficacy Study of RGN-137 Topical Gel for Junctional and Dystrophic Epidermolysis Bullosa (NCT03578029) ClinicalTrials.gov, 22 Aug 2022. clinicaltrials.gov
  31. 31Letter to stockholders: SEER-2 Phase 3 trial update RegeneRx Biopharmaceuticals, 1 Sep 2026. regenerx.com
  32. 32Safety and Efficacy of Thymosin Beta 4 Ophthalmic Solution in Patients With Dry Eye (NCT01387347) ClinicalTrials.gov, 10 Jul 2015. clinicaltrials.gov
  33. 33Thymosin β4 enhances the healing of medial collateral ligament injury in rat Regulatory Peptides, 10 Jun 2013. pubmed.ncbi.nlm.nih.gov
  34. 34Finnrick public data summary (llms-full.txt, generated 25 September 2026) Finnrick, 25 Sep 2026. finnrick.com
  35. 35TB-500 (Thymosin Beta 4) – 5MG / 10MG product page Core Peptides (vendor), accessed 8 Oct 2026. corepeptides.com (seller page, deliberately not linked)
  36. 36PubMed search: thymosin beta-4 with tendon, ligament, muscle or sports injuries (13 results, none a clinical trial) National Library of Medicine (PubMed), accessed 8 Oct 2026. pubmed.ncbi.nlm.nih.gov
  37. 37Warning letter to GenoGenix LLC (MARCS-CMS 718739) U.S. Food and Drug Administration, 20 Jan 2026. fda.gov
  38. 38Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act (categories list) U.S. Food and Drug Administration, 14 May 2026. fda.gov
  39. 39Bulk Drug Substances Nominated for Use in Compounding Under Section 503B of the Federal Food, Drug, and Cosmetic Act (categories list) U.S. Food and Drug Administration, 21 Mar 2025. fda.gov

Not medical advice. Talk to a licensed clinician before using any drug. Report an error.