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TB-500 dosage: chart, reported range and vial math

The range reported for TB-500 is 2 to 2.5 mg twice a week, then once a week. There is no human dose on record: TB-500 is a 7 amino acid fragment, and every human trial used full-length thymosin beta-4 instead. It is not approved in the US or Canada.

Last checked 10 Oct 2026Sources 17 checkedChange log

Legal status

US Not approved

Canada Not authorized

Checked 10 Oct 2026What is TB-500?

TB-500 dosage chart

Reported range, not a label dose

Pick your vial size. Each row shows the dose in milligrams or micrograms, the volume to draw and the mark on a U-100 syringe.

TB-500, 5 mg vial mixed with 2 mL of bacteriostatic water (2.5 mg/mL). Twice weekly, then weekly.
DoseVolumeSyringe units
2 mg0.80 mL80 units
2.5 mg1.00 mL100 units

Source Reported range, not a label dose. Reports describe twice a week for 4 to 6 weeks, then once a week or less. Human trials used thymosin beta-4, not TB-500. Vial math is arithmetic.

Which syringe fits each dose

For the 5 mg vial at 2.5 mg/mL.

DoseVolumeUnits0.3 mL syringe0.5 mL syringe1 mL syringe
2 mg0.80 mL80 unitsNoNoYes
2.5 mg1.00 mL100 unitsNoNoYes

How long a vial lasts

Whole doses in one vial. The row for the size picked above is marked.

Vial2 mg2.5 mg
2 mg vial1 doseNot enough
5 mg vial2 doses2 doses

How to mix a TB-500 vial

These steps are for the 5 mg vial picked in the chart. Change the size there and the amounts here change with it.

  1. Wash your hands. Wipe the stopper of the peptide vial and the water vial with an alcohol swab.
  2. Draw 2 mL of bacteriostatic water into a syringe.
  3. Push the needle through the stopper of the peptide vial and let the water run slowly down the glass, not straight onto the powder.
  4. Swirl the vial gently until the powder is gone. Do not shake it.
  5. Write the date and 2.5 mg/mL on the vial, then put it in the fridge.
VialBacteriostatic waterConcentration
2 mg vial1 mL2 mg/mL
5 mg vial2 mL2.5 mg/mL

What TB-500 is

TB-500 is a product name. The peptide identified in it is Ac-LKKTETQ, the acetylated fragment made of amino acids 17 to 23 of thymosin beta-4. It is a 7-amino-acid piece, not the full 43-amino-acid thymosin beta-4 that was used in the human trials. [1]

Other names: TB500, Ac-LKKTETQ, N-acetylated LKKTETQ, thymosin beta-4 fragment 17-23.

How it has been given to people: no human use on record.

What to know before reading a dose

  • TB-500 is not thymosin beta-4. TB-500 is a 7-amino-acid acetylated fragment [1], [2]; thymosin beta-4 has 43 amino acids [8]. Every human trial found used full-length thymosin beta-4: synthetic by vein [5], recombinant by vein [6], eye drops [7] or applied to ulcers [8]. No human study of TB-500 was found.
  • There is no human dose of TB-500 on record. Doses from thymosin beta-4 trials must not be presented as TB-500 doses.
  • No study found gave either molecule to people by injection under the skin.
  • ClinicalTrials.gov record NCT07487363 [12], titled as a TB-500 trial in heart disease, says in its own summary that it is a fictional study. It is not evidence of a human TB-500 trial.
  • Products sold online as TB500 or TB1000 did not consistently contain what they were described as containing [4].
  • FDA no longer lists the fragment in category 2. Its page, current as of 22 April 2026, shows it under substances previously in category 2 whose nominations were withdrawn [13], and the 14 May 2026 category list does not contain it [14].
  • WADA prohibits thymosin beta-4 and its derivatives, naming TB-500, at all times under section [2].3 of the 2026 Prohibited List [15].

What the evidence shows

Each finding is tagged by the kind of study it comes from. Human trials are listed first.

Randomized human trial

Full-length thymosin beta-4 is a 43-amino-acid peptide. A synthetic copy applied to venous leg ulcers was tested in a Phase 2 trial of 73 patients, where the 0.03% strength was reported as possibly speeding healing. [8]

Randomized human trial

Full-length synthetic thymosin beta-4 was given by vein to healthy volunteers in four groups of 10 at 42, 140, 420 or 1260 mg, as a single dose and then daily for 14 days. This was thymosin beta-4, not TB-500. [5]

Randomized human trial

That intravenous study reported no dose-limiting toxicity or serious adverse events over 14 days. [5]

Randomized human trial

Recombinant human thymosin beta-4 (code NL005) was given by vein to 54 healthy volunteers as single doses from 0.05 to 25.0 micrograms per kg; 30 volunteers were enrolled for daily doses over 10 days. This was thymosin beta-4, not TB-500. [6]

Randomized human trial

Eye drops containing 0.1% thymosin beta-4 (RGN-259) were tested in a Phase 3 trial in neurotrophic keratopathy: complete healing at 4 weeks in 6 of 10 treated and 1 of 8 on placebo (p = 0.0656). This was thymosin beta-4, not TB-500. [7]

Human observational study

In a clinic chart review, 4 patients were given a product called TB4 together with BPC 157 into the knee joint. The abstract does not say whether it was full-length thymosin beta-4 or the TB-500 fragment, and gives no dose. [10]

Animal study

In that doping-control study, horses were given a single dose of TB-500 containing 10 mg of the peptide so that it could be detected in urine and plasma. It was not a study of benefit. [2]

Animal study

In rats given TB-500 into the abdomen for four weeks after Achilles tendon repair, tendon structure scores and strength were better than in controls. The abstract itself calls TB-500 synthetic thymosin beta-4. [9]

Animal study

In the same rat study, giving TB-500 together with BPC-157 added nothing over either one alone. [9]

Animal study

A 2026 review for orthopaedic physicians found that thymosin beta-4 and TB-500 helped tissue repair in preclinical models but that human orthopaedic data are lacking. [11]

Lab study

Laboratory analysis of a TB-500 product identified its peptide as Ac-LKKTETQ, the N-terminal acetylated 17-23 fragment of human thymosin beta-4. [1]

Lab study

An equine doping-control study described TB-500 in 2012 as a veterinary preparation whose key ingredient is LKKTETQ with an acetyl group added to the N-terminus. [2]

Lab study

A 2024 metabolism study states that the biological effects of TB-500 itself have not been documented. [3]

Lab study

In that study, only one breakdown product (Ac-LKKTE) showed significant wound-healing activity in fibroblast cell tests; the authors suggest activity credited to TB-500 may come from this metabolite. [3]

Lab study

Analysis of TB500 and TB1000 products sold online found that what they contain does not consistently match how they had been described. [4]

Side effects and warnings

Reported in human studies or on a label:

  • No human safety data exist for TB-500 itself. FDA says it lacks the information to know whether it would cause harm in humans. [13]
  • FDA says compounded versions of the fragment may carry a risk of immune reactions because of possible clumping and peptide impurities. [13]
  • For full-length thymosin beta-4 given by vein (not TB-500), adverse events in healthy volunteers were infrequent and mild or moderate. [5]
  • For recombinant full-length thymosin beta-4 given by vein (not TB-500), adverse events were mild to moderate. [6]

TB-500 has no approved label in the US or Canada for this use, so there is no official list of who should not use it, no interaction list and no missed-dose rule.

Storage

Keep an unmixed vial the way its label says. Once it is mixed, keep it in the fridge, do not freeze it, and write the mixing date on the vial.

TB-500 dosage questions

How many units is 2.5 mg of TB-500 from a 5 mg vial?

Mixed with 2 mL of bacteriostatic water, a 5 mg vial is 2.5 mg/mL. 2.5 mg is 1.00 mL, which is 100 units on a U-100 syringe.

How much water goes in a 5 mg TB-500 vial?

2 mL gives 2.5 mg/mL. At that strength the doses in the chart sit at 80, 100 units on a U-100 syringe.

How many doses are in a 5 mg vial?

Whole doses in one vial: 2 at 2 mg, 2 at 2.5 mg.

Is TB-500 approved in the US?

Not FDA approved. FDA lists the thymosin beta-4 fragment LKKTETQ, also known as TB-500, among bulk substances that were in compounding category 2 until the nominations were withdrawn, and says it has found no human exposure data for it.

Is TB-500 authorized in Canada?

Not authorized in Canada. Health Canada names TB-500 among unauthorized injectable peptide drugs it has seized (advisory of 9 April 2026).

What human dosing data is there for TB-500?

TB-500 is not thymosin beta-4. TB-500 is a 7-amino-acid acetylated fragment; thymosin beta-4 has 43 amino acids. Every human trial found used full-length thymosin beta-4: synthetic by vein, recombinant by vein, eye drops or applied to ulcers. No human study of TB-500 was found.

Sources

Each one was opened on 10 Oct 2026 and matched to the line it supports.

  1. Esposito S et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal 2012. PubMed 22962027.
  2. Ho EN et al. Doping control analysis of TB-500, a synthetic version of an active region of thymosin beta4, in equine urine and plasma by liquid chromatography-mass spectrometry. J Chromatogr A 2012. PubMed 23084823.
  3. Rahaman 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. J Chromatogr B Analyt Technol Biomed Life Sci 2024. PubMed 38382158.
  4. Delcourt V et al. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Test Anal 2023. PubMed 36482504.
  5. Ruff D et al. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci 2010. PubMed 20536472.
  6. Wang X et al. A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin beta4 in healthy Chinese volunteers. J Cell Mol Med 2021. PubMed 34346165.
  7. Sosne G et al. 0.1% RGN-259 (Thymosin beta4) 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. PubMed 36613994.
  8. Guarnera G et al. The effect of thymosin treatment of venous ulcers. Ann N Y Acad Sci 2010. PubMed 20536470.
  9. Bicer O et al. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. Jt Dis Relat Surg 2026. PubMed 42542926.
  10. Lee E et al. Intra-Articular Injection of BPC 157 for Multiple Types of Knee Pain. Altern Ther Health Med 2021. PubMed 34324435.
  11. Mayfield CK et al. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. Am J Sports Med 2026. PubMed 41476424.
  12. TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD ClinicalTrials.gov 2026. clinicaltrials.gov. Trial NCT07487363.
  13. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks US Food and Drug Administration 2026. fda.gov.
  14. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act US Food and Drug Administration 2026. fda.gov.
  15. World Anti-Doping Code International Standard Prohibited List 2026 World Anti-Doping Agency 2026. wada-ama.org.
  16. Think twice before injecting peptides bought online: unauthorized products can seriously harm you Health Canada 2026. recalls-rappels.canada.ca.
  17. Unauthorized injectable peptide drugs seized from Optimum Wellness Centre in Calgary, Alberta may pose serious health risks Health Canada 2025. recalls-rappels.canada.ca.

Looked for and not found

  • Any human study of TB-500 (Ac-LKKTETQ): none found. PubMed searches for TB-500, TB500 and Ac-LKKTETQ with patients, volunteers, case report or clinical trial returned only reviews and doping-test methods.
  • Any human dose of TB-500, by any route. The doses list is empty on purpose: thymosin beta-4 trial doses are a different molecule given by a different route and are recorded under evidence instead.
  • Any human study of thymosin beta-4 or TB-500 injected under the skin. A PubMed search for thymosin beta-4 with subcutaneous and patients or volunteers returned only laboratory papers.
  • A human half-life for TB-500. For full-length thymosin beta-4 the intravenous study abstract [5] says half-life rose with dose but gives no figure.
  • An approved product or label for TB-500 or thymosin beta-4 in the US or Canada.
  • What the TB4 product injected in [10] actually was, and its dose.
  • Human study of TB-500 or thymosin beta-4 given together with BPC-157: only the 4 knee patients in [10]. No trial was found.
  • Posted results of the RGN-259 dry eye Phase 3 trials (ARISE) were not opened in this session.

Change log

10 Oct 2026Page published. 17 sources checked. Vial math added for the 2 and 5 mg vials.

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