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TB-500 Half-Life: How Long It Stays in Your System

How long TB-500 stays in the body, how that shapes dosing frequency, and what is known about drug testing.

Medically reviewed by Juan Pablo Frías, MD · · DisclosureSynthetic fragment of thymosin beta-4Updated
Half-life
Not found
No published half-life found (PubMed search, 2 Oct 2026)
Dosing interval
Varies by study
as used in studies
WADA
Prohibited (S2.3)
In and out of competition
Detection window
2 findings
from anti-doping studies, below

TB-500 half-life

Half-life: no published half-life found (PubMed search, 2 Oct 2026). A half-life depends on the route (under the skin, into a vein, by mouth or nasal spray), so we report it per route with the study it came from.

What half-life means

Half-life is the time it takes for the amount of a drug in the blood to fall by half. After one half-life, about 50% is left; after two, about 25%; after four to five, only a few percent remain.

  • A long half-life lets a drug be dosed less often, for example once a week.
  • A short half-life means levels rise and fall quickly, which is why some peptides are given daily or more often.
  • Effects can outlast blood levels, so half-life alone does not tell you how long a drug works.

What it means for dosing frequency

Dosing intervals used in published studies of TB-500:

Changing the interval changes how much drug builds up between doses, so it is not a free choice.

Drug tests and sport

Prohibited by WADA (S2.3)

TB-500 is named as a thymosin-beta-4 derivative in S2.3 (growth factors), prohibited at all times.

Detection findings from anti-doping analytical studies:

Tested athletes should treat it as prohibited (s2.3) at all times.

Common questions

How long does TB-500 stay in your system?

We found no published half-life for TB-500 (PubMed search, 2 Oct 2026). As a rule, most of a dose is cleared after about four to five half-lives.

What is the half-life of TB-500?

No published half-life was found in our PubMed search, 2 Oct 2026. We add one with its source and route if a study reports it.

Is TB-500 on the WADA prohibited list?

Yes. Prohibited by WADA (S2.3).

More on TB-500

DosageDoses used in published studies, with the source for each.CalculatorVial, water and dose to syringe units.Side effectsWhat labels and studies report, and what is unknown.ResultsStudy outcomes and when they were measured.PricePrice per mg and per week from dated listings. No vendor links.Legal statusFDA, compounding and WADA status with dates.

Sources

  1. 1Certain bulk drug substances for use in compounding that may present significant safety risks (Category 2; 'nominated but withdrawn' table, content current as of 22 Apr 2026)U.S. Food and Drug Administration · 2026fda.govAccessed 2 Oct 2026
  2. 2Pharmacy Compounding Advisory Committee meeting, 23–24 Jul 2026 (agenda and materials)U.S. Food and Drug Administration · 2026fda.govAccessed 2 Oct 2026
  3. 3World Anti-Doping Code International Standard Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
  4. 4Doping control analysis of TB-500, a synthetic version of an active region of thymosin β₄, in equine urine and plasma by liquid chromatography-mass spectrometry.Journal of chromatography. A · 2012PMID 23084823Accessed 2 Oct 2026
  5. 5Simplifying and expanding the screening for peptides <2 kDa by direct urine injection, liquid chromatography, and ion mobility mass spectrometry.Journal of separation science · 2016PMID 26578461Accessed 2 Oct 2026
  6. 6A 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 · 2021PMID 34346165Accessed 2 Oct 2026
  7. 7Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial.Cornea · 2015PMID 25826322Accessed 2 Oct 2026
  8. 8A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers.Annals of the New York Academy of Sciences · 2010PMID 20536472Accessed 2 Oct 2026
  9. 9Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study.Joint diseases and related surgery · 2026PMID 42542926Accessed 2 Oct 2026
  10. 10PubMed search: ("TB-500"[tiab] OR TB500[tiab] OR "thymosin beta-4"[tiab] OR "thymosin beta4"[tiab] OR Tbeta4[tiab]) (1199 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  11. 11PubMed search: ("TB-500"[tiab] OR TB500[tiab] OR "thymosin beta-4"[tiab] OR "thymosin beta4"[tiab] OR Tbeta4[tiab]) AND (humans[mh] OR patients[tiab]) (678 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  12. 12PubMed search: ("TB-500"[tiab] OR TB500[tiab] OR "thymosin beta-4"[tiab] OR "thymosin beta4"[tiab] OR Tbeta4[tiab]) AND (randomized[tiab] OR clinical trial[pt]) (18 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  13. 13PubMed search: ("TB-500"[tiab] OR TB500[tiab] OR "thymosin beta-4"[tiab] OR "thymosin beta4"[tiab] OR Tbeta4[tiab]) AND (half-life[tiab] OR pharmacokinetic*[tiab]) (16 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  14. 14PubMed search: ("TB-500"[tiab] OR TB500[tiab] OR "thymosin beta-4"[tiab] OR "thymosin beta4"[tiab] OR Tbeta4[tiab]) AND (wound[tiab] OR dermal[tiab] OR skin[tiab] OR hair[tiab]) (212 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  15. 15PubMed search: ("TB-500"[tiab] OR TB500[tiab] OR "thymosin beta-4"[tiab] OR "thymosin beta4"[tiab] OR Tbeta4[tiab]) AND (tendon[tiab] OR muscle[tiab] OR cardiac[tiab] OR myocardial[tiab] OR heart[tiab]) (246 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  16. 16PubMed search: "TB-500"[tiab] OR TB500[tiab] OR "Ac-LKKTETQ"[tiab] (33 results)PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026

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