CalcMyPeptide
Healing & RecoveryAlso known as: TB4, Tβ4, Full-length thymosin beta-4

Thymosin Beta-4

Thymosin Beta-4 (TB4) is the complete, towering 43-amino-acid parent molecule from which TB-500 is derived. Naturally ubiquitous in almost all human cells, it is the absolute biological master of cellular repair and cytoskeletal regeneration. In elite clinical protocols, full-length TB4 is deployed to force the aggressive healing of catastrophic cardiac tissue post-myocardial infarction, rapidly regenerate shattered corneas, and orchestrate the systemic repair of torn muscles, tendons, and ligaments.

Reviewed by CalcMyPeptide Editorial Team
Last updated: April 2026Evidence: Moderate1 peer-reviewed citation

Quick Stats

Half-Life~2 hours
Dose Range750-2000 mcg/day
Frequency1× daily for 10-20 days
Vial Sizes5 mg
BioavailabilitySubcutaneous injection, ocular drops (research)
Year Developed1981

Scientific Data

Molecular Formula
C212H350N56O78S
Molecular Weight
4963.4 g/mol
CAS Number
PubChem ID

Mechanism of Action

Thymosin Beta-4 (Tβ4) is a highly conserved, naturally occurring 43-amino acid peptide found in virtually all animal cells (especially high in platelets). It is the primary actin-sequestering molecule in human cells — binding to G-actin monomers to regulate the cell cytoskeleton assembly, which is essential for cell shape, motility, and migration.

Upon tissue injury, Tβ4 is released to promote angiogenesis, stem cell migration to the injury site, and wound healing. It modulates inflammatory cytokines and prevents apoptosis. In sports and regenerative medicine, TB-500 (a synthetic fragment containing its active region) is often favored, though the full 43-AA Thymosin Beta-4 is heavily studied in clinical trials for dry eye syndrome, epidermolysis bullosa, and post-MI cardiac repair.

Source: PMID: 20514133

Background & History

Thymosin Beta-4 is the most abundant member of the beta-thymosin family, present in virtually all nucleated cells at concentrations of 0.1-0.5 mM. TB-500, the widely used research peptide, is actually a 17-amino-acid fragment of this 43-amino-acid molecule. Full-length Tβ4 has been studied for cardiac repair (RegeneRx Biopharmaceuticals), corneal wound healing (RGN-259 eye drops), and epidermolysis bullosa. It represents one of the most promising endogenous repair molecules.

Research Use Cases

  • Cardiac repair post-MI
  • Corneal wound healing
  • Hair regrowth
  • Chronic wound healing
  • Epidermolysis bullosa

Dosing Protocol

Typical Dose750-2000 mcg/day
Frequency1× daily for 10-20 days
Half-Life2 hours
Common Vial Sizes5 mg

Dosing Protocols

Systemic Regeneration / Injury

Dose
2 - 5 mg
Frequency
2x per week SC
Note: Common community protocol. OFten cycled 4-6 weeks for injury recovery.

Body-Weight Dosing Reference

Estimated doses extrapolated from the published research range of 7502000 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.

WeightLowTargetHigh
120 lb(54 kg)579 mcg1061 mcg1543 mcg
140 lb(63 kg)675 mcg1238 mcg1800 mcg
160 lb(73 kg)782 mcg1434 mcg2086 mcg
180 lb(82 kg)879 mcg1611 mcg2343 mcg
200 lb(91 kg)975 mcg1788 mcg2600 mcg
220 lb(100 kg)1071 mcg1964 mcg2857 mcg
250 lb(113 kg)1211 mcg2220 mcg3229 mcg

💉 For exact syringe units based on your vial concentration, use the Thymosin Beta-4 Reconstitution Calculator →

Administration

Route
Subcutaneous injection
Timing
Timing not strictly critical. Generally split across the week.
Fasting Required?
No — food timing not critical

Expected Timeline

Week 1-3
Reduced deep tissue inflammation. Accelerated wound healing.
Week 4-6
Improved joint and tendon mobility. Recovery from persistent soft-tissue injuries.

Who Is It For?

Soft Tissue Repair / Tendons

Moderate

Promotes actin-mediated cell migration to injury sites. Wide anecdotal and preclinical support.

Cardiac / Ischemia Recovery

Low

Clinical trials evaluating efficacy in protecting myocardium post-heart attack.

Reconstitution Example

Vial
5 mg
Water
2 mL
Concentration
2.5 mg/mL
Per Unit (100u syringe)
25 mcg
Dose of 750 mcg = 30 units on a 100-unit insulin syringe

Safety & Considerations

Research compound in many jurisdictions. Do not use in individuals with active malignancy, as it promotes angiogenesis and cell migration (which could theoretically aid tumor metastasis).

Regulatory & Legal Status

FDA Status (US)
Research Only
WADA Status (2026)
Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.

Classification

Research Chemical

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Interactions & Contraindications

Research compound — no established drug interactions. Theoretical concern with tumor promotion in predisposed individuals (actin dynamics role in metastasis) though not observed in clinical studies.

Synergies & Common Stacks

TB-500 is the fragment; full-length Tβ4 contains the complete molecule. Some practitioners use both at different phases of recovery.

Tβ4 + BPC-157 targets distinct repair pathways: Tβ4 for actin dynamics/cell migration, BPC-157 for angiogenesis and GH receptor upregulation.

Dosing Quick Reference

Thymosin Beta-4— Dosing Guide
Dose Range
750-2000 mcg/day
Half-Life
2 hours
Frequency
1× daily for 10-20 days
Route
Subcutaneous
5 mg vial
💧 2 mL BAC water📐 2.5 mg/mL concentration💉 25 mcg/unit (100u syringe)
Healing & Recoverycalcmypeptide.com

Frequently Asked Questions

Is Thymosin Beta-4 the same as TB-500?
Colloquially yes, but scientifically no. True Thymosin Beta-4 is a 43-amino acid chain. Synthetic TB-500 is typically a smaller 7-amino-acid fragment (the active LKKTETQ actin-binding domain) which is cheaper to produce and has a slightly longer half-life.

References

  1. Goldstein AL et al. "Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues".” Trends in Molecular Medicine (2012). PMID: 22115354

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