Research Reference
Thymosin Beta-4
Full-length 43-amino-acid tissue repair peptide — parent of TB-500
Research & educational purposes only. BioMaxFit does not sell, promote, or represent peptides in any way. We are strictly educational and recommend working with your doctor on anything health-related. The information below comes from published research and documents what has been studied, not what should be done. Many of these compounds are investigational and not approved by the FDA; possession or use outside an authorized clinical trial may be illegal in your jurisdiction. This is not medical advice.
Thymosin Beta-4 (TB-4) is a naturally occurring 43-amino-acid peptide involved in tissue repair, angiogenesis, and cell migration. It's the most abundant actin-sequestering molecule in mammalian cells and the parent molecule of the TB-500 fragment.
No FDA-approved human dosing exists. Everything below is extrapolated from animal research and community experience.
Community protocol: loading dose of 500 mcg–1 mg daily for 2 weeks, then maintenance of 500 mcg twice weekly for 2–6 additional weeks. TB-4 contains the full LKKTET angiogenesis domain that the TB-500 fragment lacks.
Dosing Reference
Reconstitution
Add 2 mL bacteriostatic water to the 10 mg vial. Resulting concentration: 5 mg/mL.
| Dose | Syringe Units | mL Volume | Schedule |
|---|---|---|---|
| 750 mcg | 15 units | 0.15 mL | 2x/week SubQMaintenance |
| 1.5 mg | 30 units | 0.3 mL | 2x/week SubQLoading (weeks 1–4) |
| 2.5 mg | 50 units | 0.5 mL | Weekly SubQ |
Math assumes U-100 insulin syringes (1 mL = 100 units). Verify your syringe matches before use. Round half-units to the nearest visible mark.
Reconstitution
For a 10 mg vial with 2 mL bacteriostatic water, the concentration is 5 mg/mL. A 750 mcg dose draws to 15 units (0.15 mL); a 1 mg dose to 20 units (0.2 mL).
Gently swirl — do not shake. Refrigerate at 2–8°C and discard after 28 days.
Cycling Protocol
TB-4 uses a two-phase approach: loading then maintenance.
Loading phase: 500 mcg to 1 mg daily for 2 weeks to achieve tissue saturation. TB-4's short plasma half-life (~2 hours) means frequent dosing is needed for consistent tissue-level concentrations.
Maintenance phase: 500 mcg twice weekly for 2–6 additional weeks. This sustains support while reducing peptide consumption. This mirrors tissue repair timelines seen in animal studies — rapid cell migration and angiogenesis in weeks 1–2, followed by ECM remodeling in weeks 3–8 (Malinda et al., 1999).
Typical protocol lengths: Tendon/ligament/muscle injuries: 4–6 weeks. Skin and wound healing: 4–8 weeks. Post-surgical recovery: 6–8 weeks. Chronic inflammatory conditions: 8–12 weeks with cycling.
Routes of Administration
Subcutaneous (most common): For localized injuries, community protocols describe injecting within a few inches of the injury site. For systemic healing, the abdomen or anywhere with subcutaneous fat is used. A 29–31 gauge insulin syringe is commonly cited.
Peri-lesional: Direct injection around wound sites, used in dermal wound research.
Stacking Protocols
TB-4 + BPC-157 (Popular Healing Stack)
| Peptide | Dose | Route | Timing | Purpose | | --- | --- | --- | --- | --- | | TB-4 | 750 mcg daily (loading) / 500 mcg 2x/week (maintenance) | SC | AM | Actin remodeling, cell migration, anti-inflammatory | | BPC-157 | 250–500 mcg daily | SC (near injury) | AM | Angiogenesis, growth factors, GI protection |
TB-4 vs TB-500
| Parameter | TB-4 | TB-500 | | --- | --- | --- | | Structure | Full 43-amino-acid peptide | Synthetic 17–23 AA fragment | | Weekly dose | 5–10 mg (loading) | 3.5 mg (500 mcg daily) | | Contains LKKTET | Yes (angiogenesis domain) | No | | Primary use | Broad tissue repair + angiogenesis | Focused actin migration |
Side Effects & Safety
- Injection site irritation — mild, transient
- Rare mild fatigue — occasional community report
- No hormonal disruption — unlike some peptides
- Phase I human safety — IV doses up to 1,260 mg well-tolerated with no serious adverse events
- No mutagenic or carcinogenic effects in long-term animal studies
- Theoretical angiogenic concern — pro-angiogenic effects raise questions about existing tumors, though no evidence of tumor promotion exists
- No long-term human data at community doses
Research Basis
Community TB-4 doses are conservatively extrapolated from a large body of animal research, with some reference to human safety data.
Animal Study Doses: Nearly all TB-4 research uses 6 mcg/mouse IP (~0.24 mg/kg). Using standard allometric scaling to a 70 kg human gives a human equivalent of ~17 mg single dose, or ~5–10 mg/week. Community doses (5–10 mg/week loading, 2–5 mg/week maintenance) sit in the conservative middle of this range.
Phase I Human Safety (Ruff et al., 2010, PMID 20536472): Massive IV doses of 42, 140, 420, and 1,260 mg were well-tolerated in healthy subjects — no dose-limiting toxicity. This was safety testing, not therapeutic dosing.
Key mechanisms: Actin sequestration for cell migration (Mannherz & Huff, 2011, PMID 22127247), VEGF-driven angiogenesis (Philp et al., 2003, PMID 14500546), NF-kB suppression for anti-inflammatory effects (Sosne et al., 2007, PMID 17254567), and Akt survival signaling (Bock-Marquette et al., 2004, PMID 15565145).