TB-500 (Thymosin β4 Fragment)

Mechanism of action: Actin regulation; Cell migration; Angiogenesis; Tissue remodeling; Wound repair; (Much of this evidence comes from studies of the native protein rather than TB-500 specifically.)

Proposed indications: Tendon healing; Ligament healing; Muscle recovery; Wound healing; Corneal repair

Commonly reported by peptide clinics†: 2-2.5 mg loading (1-2x/week), then 2-2.5 mg every 2 weeks maintenance

Peptide clinics and compounding pharmacies commonly report a loading phase of 2-2.5 mg once or twice weekly for 4-6 weeks, followed by a maintenance dose of 2-2.5 mg every 2 weeks. This convention is specific to TB-500 (the synthetic fragment) -- it should not be conflated with human research on native, full-length thymosin β4, which is a different body of evidence entirely (see this entry's own notes above on that distinction).

†Reported by peptide clinics and compounding pharmacies -- not derived from human clinical trials. Not an individualized recommendation. Actual use should be supervised by a qualified provider.

Typical clinical dosing schedule: No established clinical dosing. Use outside of research lacks validated protocols and regulatory approval.

Administration: Subcutaneous injection (typically discussed in research settings; no approved pharmaceutical formulation exists) — No established clinical dosing

Compare with: BPC-157GHK-Cu (Copper Tripeptide-1)

An "emerging / limited evidence" rating means rigorous research hasn't caught up yet -- not that this peptide doesn't work. Many peptides in this category are newer or simply understudied rather than proven ineffective.

Evidence rating: ⭐☆☆☆☆ — Evidence for TB-500 itself is sparse; stronger evidence exists for full-length thymosin β4 in experimental settings.

Landmark trials: Native thymosin β4 research — Has demonstrated roles in wound healing, corneal repair, and tissue regeneration in preclinical models. Clinical evidence for TB-500 remains minimal.

Common side effects: Injection-site reactions, Hypersensitivity (human safety data are insufficient)

Serious risks: Unknown long-term safety; Potential effects on angiogenesis and tissue growth; Variable product quality in unregulated markets

Drug interactions: No established interaction profile.

Legal status: Not FDA-approved for human use. This is a research compound, not a medication — any use should only occur under the direction of a licensed healthcare provider, and its legal availability varies and changes frequently. Verify current status independently before considering use.

Regulatory status: Research peptide • Not FDA approved • WADA Prohibited (competition)

Contraindications: Not established. Avoid in:; Pregnancy; Active malignancy; Children; Competitive athletes subject to anti-doping rules

Pregnancy & breastfeeding: Avoid due to lack of safety data.

Goldstein AL, Kleinman HK. (2015). Advances in the basic and clinical applications of thymosin β4. Expert Opinion on Biological Therapy. Malinda KM, et al. (1999). Thymosin β4 accelerates wound healing. Journal of Investigative Dermatology.