TB-500
Thymosin Beta-4 Fragment
TB-500 is a synthetic peptide fragment derived from Thymosin Beta-4 (Tβ4), specifically the actin-binding domain sequence Ac-LKKTETQ, primarily used for tissue repair, wound healing, and recovery from musculoskeletal injuries. It is widely used in research and performance contexts for accelerating healing of tendons, ligaments, muscles, and reducing inflammation following acute or chronic injury. TB-500 has gained popularity among athletes and bodybuilders for its purported ability to enhance flexibility and promote systemic healing responses.
Mechanism of Action
TB-500 works primarily by sequestering G-actin monomers through its LKKTETQ motif, thereby regulating actin polymerization dynamics, which is critical for cell migration, proliferation, and tissue remodeling. It upregulates cell-surface receptors such as integrins and promotes angiogenesis via vascular endothelial growth factor (VEGF) pathways, facilitating new blood vessel formation and oxygen delivery to injured tissue. Additionally, TB-500 modulates inflammatory cytokine activity, reduces fibrosis, and promotes differentiation of progenitor cells at the site of injury.
Evidence by Health Goal(18 goals)
Dosing Protocols
Subcutaneous injection, timing relative to meals not critical
Cycle: Loading phase: 4-6 weeks at 2-2.5mg twice weekly; Maintenance phase: 2-2.5mg once weekly for 4-6 weeks
Reconstitute lyophilized powder with bacteriostatic water. Subcutaneous injection into abdominal fat or near the site of injury is most common. Some protocols use intramuscular injection. Total weekly dose of 4-5mg is typical during loading.
Safety & Side Effects
TB-500 has a relatively favorable short-term safety profile in animal studies and anecdotal human use, with no severe adverse events widely documented at standard research doses; however, it is not approved for human use by the FDA or EMA, and long-term human safety data are absent. The angiogenic and cell-proliferative mechanisms raise a theoretical oncological concern — use is contraindicated in individuals with a history of cancer or undiagnosed masses, and it remains a gray-market research compound in most jurisdictions.
Possible Side Effects
- !Transient lethargy or fatigue in the hours following injection
- !Mild nausea occasionally reported, typically dose-dependent
- !Injection site redness, swelling, or irritation
- !Headache following administration, usually resolving within hours
- !Potential promotion of pre-existing undiagnosed tumor growth due to angiogenic properties
- !Dizziness or lightheadedness in rare cases
- !Flu-like symptoms during initial loading phase
Interactions
- -May potentiate anticoagulant effects of warfarin or other blood thinners due to influence on fibrin and tissue remodeling pathways — monitor clotting parameters
- -Additive tissue-repair and angiogenic effects when combined with BPC-157; combination is common but increases theoretical proliferative risk
- -May enhance effects of growth hormone or IGF-1 peptides on tissue growth; combination increases both efficacy and uncertain risk profile
- -Use caution with NSAIDs — anti-inflammatory mechanisms may partially overlap, and NSAIDs may blunt the inflammatory signaling required for optimal tissue remodeling
- -Theoretically contraindicated alongside VEGF-targeting cancer therapies (e.g., bevacizumab) due to opposing mechanisms of action
Cost & Where to Buy
Pricing reflects research-grade lyophilized powder from peptide vendors, typically sold in 5mg vials. A standard loading phase cycle of 4-6 weeks at 4-5mg/week requires approximately 16-30mg total. Purity and vendor reputation significantly affect price; third-party tested sources command a premium.
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