RESEARCH CHEMICAL ONLY — FOR IN VITRO / LABORATORY USE
This information is provided exclusively for educational and scientific reference purposes. This compound is NOT approved by the FDA or any regulatory agency for human or veterinary use. Administration into living organisms is FORBIDDEN BY LAW in many jurisdictions without appropriate licensure. All data presented here is sourced from peer-reviewed literature and is intended solely for in vitro (outside-the-body) research contexts.
This website does not provide medical advice, diagnosis, or treatment. Consult a licensed physician before making any health-related decisions.
What Is TB-500?
TB-500 is a synthetic peptide marketed as a version of Thymosin Beta-4 (Tβ4), a naturally occurring 43–amino-acid protein found in virtually all human and animal cells. Tβ4 is released at sites of injury by platelets and macrophages and is best known as a major intracellular actin-sequestering protein — it binds monomeric G-actin and regulates the availability of actin for cytoskeletal assembly, a process central to cell migration, angiogenesis, and tissue repair.
An important accuracy note distinguishes TB-500 from full-length Tβ4. While the two names are used interchangeably in consumer channels, the analytical literature — including Esposito et al. (2012) on synthesis and characterization — describes many commercial “TB-500” products as corresponding to an N-terminally acetylated active fragment of thymosin β4 rather than the complete 43-residue protein. The chemical identity shown on this page reflects full-length Tβ4 (the PubChem-referenced entity); actual product composition varies by supplier. Because its repair mechanisms are complementary, TB-500 is frequently studied alongside BPC-157 in soft-tissue models.
Research Context
Evidence Level: The following summarizes findings from peer-reviewed preclinical studies (animal models and in vitro experiments), with a small number of clinical trials in ophthalmology. No large-scale human trials support musculoskeletal or performance uses. Findings should not be interpreted as clinical recommendations.
Overview
The thymosin β4 literature spans roughly 960 PubMed-indexed publications and clusters around five themes: the molecular mechanism of actin regulation, cardiac and vascular repair, wound healing and ocular-surface regeneration, neurological applications, and — most recently — safety and regulatory framing within sports medicine. Evidence maturity is highest for the mechanistic and ophthalmic work (which has reached clinical trials for dry eye and neurotrophic keratopathy) and remains preclinical for the musculoskeletal and cardiac applications most associated with the “TB-500” research name.
Molecular Mechanism: Actin Regulation
The defining biochemistry of Tβ4 is actin-monomer sequestration. Bubb (2003) characterized Tβ4 as a small (~5 kDa), largely unfolded peptide whose effects on the actin cytoskeleton are explained by its defined actin-binding interactions. Sun et al. (2007) placed Tβ4 within the broader network of actin-regulating proteins, describing how it modulates the pool of polymerization-ready actin monomers alongside nucleating and severing factors. This control of cytoskeletal dynamics is the mechanistic basis for the peptide’s reported effects on cell migration and angiogenesis across tissue types.
Cardiac and Vascular Repair
Tβ4 has been studied extensively in cardiac injury models. Pipes and Zhang (2017) reviewed preclinical cardiac-ischemia work in which Tβ4 was associated with reduced infarct volume together with antifibrotic and proangiogenic (blood-vessel-forming) activity. The proposed mechanism links actin regulation to endothelial and progenitor-cell migration, promoting revascularization of ischemic tissue — a theme that connects the cardiac findings to the peptide’s wound-healing profile.
Wound Healing and Ocular-Surface Regeneration
The most clinically advanced Tβ4 research is in ophthalmology. Sosne (2019) reviewed the peptide’s ocular-repair applications and referenced Phase 3 clinical trials in dry-eye disease and neurotrophic keratopathy — the strongest human-trial signal in the dataset. Foundational reviews such as Goldstein et al. (2012) describe Tβ4 as an injury-released peptide that promotes cell migration and mobilizes stem/progenitor cells, mechanisms shared across dermal, corneal, and internal wound-healing models.
Neurological and Regenerative Directions
Emerging work extends Tβ4 into neurodegeneration and organ regeneration. Zeng et al. (2025) used iPSC-derived cerebral organoids carrying familial Alzheimer’s APP mutations to identify thymosin β4 as a candidate intervention target. Bock-Marquette et al. (2023) positioned Tβ4 within regenerative and aging biology, linking developmental signaling pathways to potential organ-regeneration directions. These are early-stage findings, not clinical evidence.
Methodological Observations
The Tβ4 literature is dominated by in vitro and rodent studies, with actin-binding assays, infarct-volume measurement, and wound-closure rates as common endpoints. Several foundational mechanistic reviews predate 2015, reflecting the maturity of the actin-regulation science, while translational and safety work has accelerated since 2019. The ophthalmic program is the principal source of controlled human data; musculoskeletal and cardiac applications remain preclinical.
Research Gaps and Limitations
- Evidence level gap — Outside ophthalmology, no large randomized controlled trials support the musculoskeletal, cardiac, or performance uses associated with TB-500.
- Identity gap — Commercial “TB-500” may be a fragment rather than full-length Tβ4 (Esposito et al., 2012); product composition is not standardized.
- Translational gap — Animal dosing has not been validated against human-equivalent doses; the widely quoted weekly milligram ranges are extrapolations, not trial-derived.
- Safety gap — Long-term safety data are limited; Belsky et al. (2019) reviewed anti-inflammatory effects in preclinical sepsis models but did not establish a chronic human safety profile.
- Regulatory context — Mendias et al. (2026) situate Tβ4 among unapproved “gray-market” peptides in sports medicine; it is prohibited in sport by anti-doping authorities.
Reconstitution Mathematics
Accurate reconstitution is critical for consistent dosing in any laboratory protocol. The interactive calculator on this page handles all the arithmetic — but understanding the underlying formula is useful for verification:
Concentration (mg/mL) = Vial Size (mg) ÷ BAC Water Added (mL)
Dose Volume (mL) = Desired Dose (mg) ÷ Concentration (mg/mL)
Syringe Units (IU) = Dose Volume (mL) × 100 [for U-100 insulin syringe]Common laboratory reconstitution examples:
| Vial Size | BAC Water | Concentration | 500 mcg dose |
|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 20 IU |
| 5 mg | 5 mL | 1.0 mg/mL | 50 IU |
| 10 mg | 2 mL | 5.0 mg/mL | 10 IU |
Use the interactive calculator on this page for any custom vial size, water volume, or dose.
Common Research Dosing Parameters
Based on published preclinical literature and community research conventions. These are not clinical recommendations.
TB-500 research doses are typically expressed as weekly milligram totals divided across administrations, reflecting the peptide’s role in sustained tissue-repair models:
| Tier | Weekly Total | Per-Dose Example | Frequency | Route |
|---|---|---|---|---|
| Low / maintenance | 2 mg | 1 mg | 2× per week | SC |
| Standard / loading | 4–5 mg | ~1–1.25 mg | 2–4× per week | SC |
| Extended | up to 10 mg | ~2 mg | 2–4× per week | SC |
Key observations from the literature:
- Subcutaneous administration is standard in research settings
- The peptide’s long tissue persistence supports infrequent (twice-weekly) dosing schedules
- Weekly milligram ranges are community/research conventions extrapolated from animal data, not human-trial doses
Graduated Dosing Design from Published Studies
The following graduated design reflects loading-then-maintenance patterns commonly modeled in tissue-repair research. It is not a clinical protocol.
Reconstitution assumption: 5 mg vial + 2 mL BAC water = 2.5 mg/mL concentration
| Phase | Duration | Example Dose* | Injection Volume | Syringe Units (IU) | Frequency | Route |
|---|---|---|---|---|---|---|
| Loading | Week 1–4 | 1.25 mg | 0.50 mL | 50 IU | 2× per week | SC |
| Maintenance | Week 5–8 | 1.0 mg | 0.40 mL | 40 IU | 1–2× per week | SC |
| Taper | Week 9–12 | 0.5 mg | 0.20 mL | 20 IU | 1× per week | SC |
*Example doses calculated for illustrative purposes based on common vial configurations.
Dose range sources:
- Loading/maintenance framing reflects the sustained-repair kinetics discussed in Goldstein et al. (2012) and Pipes and Zhang (2017)
- Weekly milligram ranges are research/community conventions, not values from a specific human dose-finding trial
- Mechanistic rationale for cytoskeletal/repair activity from Sun et al. (2007)
Important notes:
- These ranges are extrapolated from animal studies; no validated human dosing exists outside the ophthalmic trials, which used topical/local delivery rather than systemic injection
- IU values assume a U-100 insulin syringe (1 IU = 0.01 mL)
- Because a single dose can exceed 0.5 mL, verify total draw against syringe capacity
Stability & Storage
| State | Temperature | Duration |
|---|---|---|
| Lyophilized (dry powder) | −20 °C (freezer) | 24+ months |
| Reconstituted in BAC water | 2–8 °C (refrigerator) | Up to 30 days |
| Reconstituted, room temp | 20–25 °C | 48 hours maximum |
Bacteriostatic water (BAC water, 0.9% benzyl alcohol) is the standard diluent for reconstitution because benzyl alcohol acts as a preservative, extending the usable life of the reconstituted solution.
Reconstitution procedure (standard laboratory protocol):
- Allow vial to reach room temperature (~15 minutes)
- Wipe septum with 70% isopropyl alcohol
- Draw desired BAC water volume into a sterile syringe
- Insert needle at a 45° angle and inject slowly along the vial wall — do not inject directly onto the lyophilized cake
- Gently swirl (do not shake or vortex) until fully dissolved
- Label vial with date, concentration, and store per table above
Frequently Asked Questions
How many units do I draw for 500 mcg of TB-500?
It depends on your reconstitution ratio. With a 5 mg vial in 2 mL BAC water (2.5 mg/mL concentration), a 500 mcg dose = 20 units on a U-100 insulin syringe. For a full 1 mg research dose it would be 40 units. With 5 mL BAC water instead, 500 mcg = 50 units. Use the calculator above for your specific setup.
Can TB-500 be stacked with BPC-157?
In laboratory settings, TB-500 is frequently studied alongside BPC-157 for complementary tissue-repair mechanisms — TB-500 regulates actin and cell migration, while BPC-157 promotes angiogenesis and fibroblast activity. Their stability profiles are compatible in bacteriostatic water. Use the multi-peptide mode to compute combined injection volumes and verify the total draw does not exceed syringe capacity.
Is TB-500 the same as Thymosin Beta-4?
Not always. Full-length Tβ4 is a 43–amino-acid protein, but some commercial “TB-500” products correspond to a shorter active fragment (Esposito et al., 2012). The names are used interchangeably in the market, but composition is not standardized — check supplier documentation.
How long does reconstituted TB-500 stay stable?
Reconstituted in bacteriostatic water and stored at 2–8 °C, TB-500 is generally stable for up to 30 days. Always use a fresh alcohol swab on the vial septum before each draw. If the solution becomes cloudy or discolored, discard it.
Why is TB-500 dosed only twice a week?
Thymosin β4’s tissue-repair activity is sustained rather than acute, so research schedules typically model twice-weekly loading doses followed by a maintenance phase, rather than daily injections. This contrasts with short-half-life peptides like Ipamorelin that are dosed multiple times per day.
Is TB-500 approved for any medical use?
No. Thymosin β4 has reached Phase 3 clinical trials only in ophthalmology (dry eye and neurotrophic keratopathy). The injectable musculoskeletal and cardiac uses associated with “TB-500” remain preclinical, and the compound is prohibited in competitive sport.
FOR RESEARCH PURPOSES ONLY. Not for human consumption. Not for veterinary use. Not a drug, food, or cosmetic.