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TB-500

Synthetic fragment of thymosin beta-4. TB-500 is not FDA approved for any use.

Also called:TB4thymosin beta-4TB-500 fragment
Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated Strongest evidence: Human RCT evidence, 4 of 4
StatusPCAC voted 8–6 for 503A (Jul 2026)Removed from FDA Category 2 on 15 Apr 2026. PCAC voted 8–6 for the 503A list (Jul 2026); not finalized.Prohibited by WADA (S2.3)Full legal history

Key facts

How we verify
Class
Synthetic fragment of thymosin beta-4
Also called
TB4, thymosin beta-4
Vial sizes sold
2 mg, 5 mg, 10 mg, 20 mg
Community-reported sizes
Half-life
Not found
No published half-life found (PubMed search, 2 Oct 2026)
FDA status
Not approved
Off Category 2, 15 Apr 2026
PCAC vote
8–6 for 503A
Jul 2026, not final
WADA
Prohibited (S2.3)
In and out of competition
Everything on TB-500

TB-500 guides

DosageDoses used in published studies, with the source for each.Side effectsWhat labels and studies report, and what is unknown.CalculatorVial, water and dose to syringe units.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.How to injectSites, syringe types and hygiene, step by step.Half-lifeWhat is measured, by route, and what is not.10 mg vialConcentration and unit tables for the 10 mg size.For hairWhat research says about TB-500 for hair.
Vial and dose sizes
5 mg vial

Evidence at a glance

Human and animal counts are PubMed records from our evidence ledger (search counts, not studies we reviewed). The grade is the strongest design among the studies we summarised for that goal: a human randomized trial outweighs any number of animal studies.

TB-500: studies by condition
ConditionHuman studiesAnimal studiesStudies we summarisedEvidence grade
HairNot in our ledgerNot in our ledger1Animal evidence, 2 of 4PloS one 2015, PMID 26083021

Grades follow our evidence scale. Summarised studies come from our evidence file, each quote checked against the abstract or label.

Compared with

TB-500vsBPC-157Synthetic fragment of thymosin beta-4 next to gastric pentadecapeptide: evidence, dosing and legal status side by side.PCAC voted 8–6 for 503A (Jul 2026)Read the comparison →

Common stacks

TB-500 is often sold pre-mixed or combined with other peptides. No controlled study has tested these combinations; the pages below cover the math and what each part has been studied for.

KLOWGHK-Cu, BPC-157, TB-500 and KPV80 mg blendsBlend calculator
GLOWGHK-Cu, BPC-157 and TB-50050 mg · 70 mg blendsBlend calculator
WolverineBPC-157 and TB-50010 mg · 20 mg blendsBlend calculator

Common questions

Is TB-500 FDA approved?

No. TB-500 is not FDA approved for any use. The FDA removed it from Category 2 on 15 Apr 2026. Its advisory committee voted 8–6 in July 2026 to add it to the 503A compounding list. That vote is not final.

Is TB-500 banned in sport?

Yes. Prohibited by WADA (S2.3), so it is prohibited at all times for tested athletes.

How much water goes in a 10 mg vial?

That choice only changes the concentration. With 2 mL, the vial is 5 mg/mL. The calculator converts any amount to syringe units. It does the math only and does not suggest a dose.

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. 3US search volume and year-over-year trend, Google Keyword Planner export (Jun–Aug 2026 vs 2025)Peptigraph research · 2026peptigraph.com/methodology/Accessed 1 Oct 2026
  4. 4World Anti-Doping Code International Standard Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
  5. 5United States: No FDA-approved product found: Drugs@FDA (openFDA) search for active ingredient "TB-500" returned no matches on 2 Oct 2026.U.S. Food and Drug Administration · 2026api.fda.govAccessed 2 Oct 2026
  6. 6US compounding: TB-500 (thymosin beta-4 fragment) was removed from FDA's 503A category 2 after the nominator withdrew; FDA announced a PCAC consultation on 23 July 2026.U.S. Food and Drug Administration · 2026fda.govAccessed 2 Oct 2026
  7. 7World Anti-Doping Code: Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
  8. 8Thymosin Beta-4 Induces Mouse Hair Growth.PloS one · 2015PMID 26083021Accessed 2 Oct 2026
  9. 9Recombinant human thymosin beta 4 improves ischemic cardiac dysfunction in mice and patients with acute ST-segment elevation myocardial infarction after reperfusion.Cardiovascular research · 2025PMID 41229390Accessed 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
  17. 17Advisory committee backs 6 of 7 peptides for the 503A listNCPA · 2026ncpa.org
  18. 18FDA gives notice that 12 peptides will be removed from Category 2 (nominations withdrawn)FDA · 2026fda.govAccessed 2 Oct 2026

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