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TB-500 (Thymosin β4)
Research Use
Also known as Thymosin Beta-4, TB4-frag
Function
Primary
Wound healing · Muscle/tendon repair
Secondary
Anti-fibrotic · Cardiac repair (research)
Mechanism
Sequesters G-actin → promotes cell migration; upregulates metalloproteinases for ECM remodeling; anti-apoptotic; anti-inflammatory via NF-κB inhibition.
Evidence
Pre-clinical / Observational
Research
Phase I/II cardiac fibrosis trials (RegeneRx)
Dosing
Range
2–5 mg 2×/week (loading); 2 mg/week (maintenance)
Frequency
2×/week loading → weekly maintenance
Route
Subcutaneous · Intramuscular
Cycling
4–6 week loading then 4–6 weeks maintenance; cycle off ≥4 weeks.
Benefits
- ·Reported faster recovery from injury
- ·Anti-fibrotic effects
- ·Generally well tolerated in trials
Risks
- ·Fatigue
- ·WADA-prohibited in sport
- ·No long-term human safety data
Contraindications
- ·Active malignancy (theoretical)
- ·Competitive athletes under WADA
- ·Pregnancy
Regulatory
Not FDA-approved; compounded/research use
Cited Works
- Goldstein AL et al. Thymosin β4: Therapeutic potential. Expert Opin Biol Ther. 2012;12:37-51.source