TB-500
Thymosin Beta-4 fragment · Tβ4 fragment · TB4
Promotes cell migration and angiogenesis in models; no human efficacy trials
Overview
TB-500 is a synthetic peptide marketed as a fragment/analog of thymosin beta-4 (Tβ4), a naturally occurring regulatory peptide found in many tissues. Tβ4 is a major actin-binding protein, and the activity attributed to TB-500 centers on cell migration, blood-vessel formation, and tissue remodeling. It is used in research and community settings for soft-tissue and tendon recovery and is administered by subcutaneous injection.
As with BPC-157, the human evidence base is limited. The mechanistic and healing data for thymosin β4 and TB-500 derive largely from animal and cell-based studies; some clinical investigation of full-length thymosin β4 has been pursued for specific indications such as ophthalmic and dermal wound healing, but TB-500 itself is not an approved product and has no large-scale human efficacy trials for musculoskeletal repair. Reports of benefit in people are therefore anecdotal, and this protocol is flagged at 'community' confidence.
The dosing pattern shown — a higher-frequency 'loading' period followed by a weekly maintenance dose — reflects commonly reported community practice rather than a validated clinical regimen. Its pharmacokinetics are not formally characterized in humans, but the circulating half-life is generally described as a matter of hours, in line with other small unmodified peptides; the practical justification for weekly dosing is that the molecule binds actin throughout tissues, so its biological effects are thought to outlast its plasma levels. That tissue-retention rationale is mechanistic and community-derived rather than established by human pharmacokinetic data. All figures here are an educational research reference only.
Key parameters
- Dose range
- 2–2.5 mg twice weekly (loading), then weekly
- Frequency
- 2× weekly then weekly
- Half-life
- Plasma half-life on the order of hours; tissue effects reportedly persist days
- Route
- Subcutaneous
- Vial sizes
- 5 mg · 10 mg
- Regulatory status
- Not approved; WADA-prohibited in sport; research use only. TB-500 has no marketing authorization, and thymosin β4 / its fragments are explicitly banned in competitive athletics under World Anti-Doping Agency rules.
Mechanism of action
Actin sequestration / cytoskeletal regulation
Thymosin β4 binds monomeric G-actin and regulates actin polymerization. This cytoskeletal role is the proposed basis for enhanced cell motility and migration of repair cells toward injured tissue.
Cell migration and recruitment
By influencing the actin cytoskeleton, the peptide is reported to promote migration of endothelial and other cell types, supporting wound coverage and tissue remodeling in animal models.
Angiogenesis
Like other repair-oriented peptides, thymosin β4 is associated with new blood-vessel formation in preclinical models, improving perfusion at sites of injury.
Anti-inflammatory / remodeling modulation
Animal studies attribute modulation of inflammation and extracellular-matrix remodeling to thymosin β4, framed as contributing to its reported soft-tissue recovery effects.
Dosing protocol & phases
| Phase | Weeks | Dose | Notes |
|---|---|---|---|
| Loading (community) | Weeks 1–4 (approx) | 2–2.5 mg twice weekly | Higher-frequency phase commonly reported in community protocols; not clinically validated. |
| Maintenance (community) | After loading | 2–2.5 mg once weekly | Frequency is reduced once the initial period is complete; rationale is anecdotal. |
| Reassessment | ~6–8 weeks | Continue weekly or pause and reassess | No clinical evidence defines an optimal total duration. |
Reconstitution guide
For educational and research reference only. Not intended for human consumption, not medical advice. Compounds discussed are sold and used for laboratory research purposes only.
10 mg vial + 5 mL bacteriostatic water
Concentration2,000 mcg/mL · 2 mg/mL
| Target dose | Draw volume | U-100 units |
|---|---|---|
| 2,000 mcg | 1 mL | 100 |
| 2,500 mcg | 1.25 mL | 125 |
Lower-concentration mix that yields round, easy-to-read draws for typical 2–2.5 mg doses.
10 mg vial + 2 mL bacteriostatic water
Concentration5,000 mcg/mL · 5 mg/mL
| Target dose | Draw volume | U-100 units |
|---|---|---|
| 2,000 mcg | 0.4 mL | 40 |
| 2,500 mcg | 0.5 mL | 50 |
Higher-strength mix that keeps the same doses inside a smaller volume / single 50-unit draw.
Reconstitution calculator
Pre-filled with TB-500's vial sizes. Adjust the water volume and target dose to see the exact draw, with warnings for doses that are hard to measure or won't fit a syringe.
At 1,000 micrograms per millilitre, a 2,000 microgram dose is 2 millilitres, or 200 units on a U-100 syringe, giving 2 doses per vial.
This draw is 200 units, which won't fit in a 50-unit syringe. Use more bacteriostatic water (lower concentration) or split the dose.
Supplies needed
Affiliate disclosure: we may earn a commission from supplier links, at no extra cost to you. For research and educational use only.
Recommended supply
TB-500 — research vial
From our verified partner Dynotides, with a third-party certificate of analysis per batch.
Injection supplies
- View
Bacteriostatic water
Diluent for reconstituting lyophilized vials.
- Buy
Insulin syringes (U-100)
0.3–0.5 mL, 29–31 G for accurate small draws.
- Buy
Alcohol prep pads
Sterile swabs for the vial stopper and site.
- Buy
Sharps container
Safe disposal of used needles.
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Storage fridge
Keeps reconstituted vials at 2–8 °C.
- Buy
Insulated travel case
Cooled, TSA-friendly case for travel.
Missed-dose guidance
No approved-label guidance exists because TB-500 is not an approved drug. Given the relatively long reported duration of action and weekly maintenance schedule, community practice is to take a missed dose when remembered if it is well before the next scheduled one, and otherwise to skip it and resume the normal schedule rather than doubling up. No evidence-based recommendation can be made.
Side effects & safety
| Category | Effect | Trial incidence |
|---|---|---|
| Injection site | Local irritation, redness, or transient discomfortAnecdotal; no human-trial incidence available. | — |
| General | Reported fatigue or 'head rush' shortly after injectionCommunity-reported; not quantified in controlled human studies. | — |
| Anti-doping | Prohibited substance in sanctioned sport (WADA)Not a physiological side effect but a material risk for competitive athletes — use can trigger anti-doping sanctions. | — |
| Theoretical | Concern regarding effects on cell proliferationBecause the peptide promotes cell migration/angiogenesis, theoretical proliferation concerns are raised; human relevance is unestablished. | — |
| Safety data | Long-term human safety is uncharacterizedNo long-term human safety studies exist for TB-500; this is the principal limitation. | — |
Clinical trials & evidence
Thymosin β4 in dermal / cutaneous wound healing (preclinical)
Preclinical (animal)Varies · Rodent wound-healing models
Accelerated wound closure and increased cell migration/angiogenesis reported for thymosin β4 in animal models; not a TB-500 musculoskeletal efficacy trial.
Trial identifier needs verification
Thymosin β4 cardiac repair models (preclinical)
Preclinical (animal)Varies · Rodent models of cardiac injury
Thymosin β4 promoted cell migration and improved repair markers after cardiac injury in animal studies; human extrapolation is not supported.
Trial identifier needs verification
Full-length thymosin β4 clinical wound-healing programs
Clinical (full-length Tβ4, not TB-500)Trial-dependent · Investigated for ophthalmic (dry eye, neurotrophic keratopathy) and dermal/venous wound-healing indications
Synthetic full-length thymosin β4 — a 43-amino-acid molecule distinct from the shorter TB-500 fragment — has been advanced into human trials for select wound-healing and ophthalmic indications by its developer. These programs concern the full-length peptide and do not validate the TB-500 fragment for musculoskeletal repair; they are listed only to show where genuine human investigation of the parent molecule exists.
Trial identifier needs verification
Storage & handling
- Lyophilized
- Store the lyophilized powder refrigerated at 2–8 °C, protected from light; brief shipping excursions to room temperature are generally tolerated. Follow the supplier certificate of analysis for product-specific handling.
- Reconstituted
- After reconstitution with bacteriostatic water, refrigerate at 2–8 °C and use within roughly 28 days. Do not freeze; minimize light exposure.
Comparisons
| Vs. | Target | Half-life | Dosing | Efficacy | Status |
|---|---|---|---|---|---|
| BPC-157 | Actin-binding / thymosin β4 axis vs VEGFR2 / NO and growth-factor pathways | Plasma hours, longer-acting in tissue vs very short in plasma (~15 min IV, rats) | ~2–2.5 mg twice weekly then weekly vs 250–500 mcg daily | Both preclinical/anecdotal; frequently combined rather than compared head-to-head | Neither approved |
| GHK-Cu | Actin/cell-migration vs copper-peptide matrix-remodeling and antioxidant effects | Plasma hours (tissue-retained) vs short (small copper tripeptide) | ~2–2.5 mg weekly vs community-defined (often topical or low-dose subQ) | Both lack human musculoskeletal efficacy trials; sometimes stacked for skin/tissue support | Neither approved |
Featured in these stacks
Wolverine (BPC-157 + TB-500)
The 'Wolverine' stack pairs two of the most widely discussed repair peptides because their proposed mechanisms are complementary rather than redundant. BPC-157 is associated with angiogenesis and localized tendon/ligament/gut signaling, while TB-500 (a synthetic fragment of thymosin beta-4) is associated with actin regulation and cell migration across tissue.
GLOW (BPC-157 + TB-500 + GHK-Cu)
GLOW extends the Wolverine repair pairing with GHK-Cu, a copper-binding tripeptide associated with collagen synthesis, skin remodeling, and wound cosmesis. The idea is to combine systemic/structural repair (BPC-157 + TB-500) with a skin- and collagen-oriented signal (GHK-Cu).
KLOW (KPV + BPC-157 + TB-500 + GHK-Cu)
KLOW adds KPV — a tripeptide fragment of alpha-MSH with anti-inflammatory properties — to the GLOW stack, aiming to pair tissue/skin repair with an inflammation- and gut-oriented signal.
Sources & references
- [1]Goldstein AL, Hannappel E, Kleinman HK. Thymosin β4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med (review). ↗ source
- [2]Crockford D et al. Thymosin β4: structure, function, and biological properties supporting wound-healing and tissue-repair research. ↗ source
- [3]Ho ENM et al. Doping control analysis of TB-500, a synthetic version of an active region of thymosin β4, in equine urine and plasma. J Chromatogr A 2012 (characterizes TB-500 and its clearance). ↗ source
- [4]World Anti-Doping Agency Prohibited List (TB-500 / thymosin β4 fragments are prohibited). ↗ source
Frequently asked questions
Is TB-500 the same as thymosin beta-4?
Not exactly. TB-500 is marketed as a synthetic fragment/analog related to thymosin beta-4. Much of the supporting science is on full-length thymosin β4, and the two should not be treated as interchangeable when interpreting study results.
Why is TB-500 banned in sports?
The World Anti-Doping Agency prohibits thymosin β4 and its fragments. For anyone subject to anti-doping testing, using TB-500 carries a real risk of sanctions independent of any health considerations.
Does TB-500 have human efficacy evidence for injuries?
No large-scale human efficacy trials support TB-500 for musculoskeletal repair. The healing claims rest on animal and cell-based research plus anecdotal use, which is why this protocol is rated 'community' confidence with no asserted trial percentages.
Related protocols
BPC-157
Body Protection Compound 157
Broad tissue-repair effects in rodent models; no human efficacy trials
GHK-Cu
Copper tripeptide-1
Endogenous copper-binding tripeptide that declines with age
Looking to match this protocol to a verified research vial? Our partner supplier publishes a certificate of analysis per batch.
For educational and research reference only. Not intended for human consumption, not medical advice. Compounds discussed are sold and used for laboratory research purposes only.