What the current evidence can establish
Human safety studies located for this evidence review evaluated full thymosin beta-4 or route-specific formulations, not the commercially named TB-500 fragment used for musculoskeletal claims.
- A small or route-specific study cannot characterize uncommon or long-term adverse effects.
- Absence of reported events is not proof that a compound or product is safe.
- Research-vendor identity, purity, sterility, endotoxin, and stability remain separate risks.
What this evidence review covers
Explain that full-length Tβ4 tolerability studies do not define TB-500 fragment safety.
- Entity-specific safety table
- Full-length IV phase 1 findings
- Full-length ophthalmic phase 2 findings
- Fragment-specific FDA unknowns
- Vendor-product quality risks
Source-backed findings
Each claim below is tied to the evidence class that can support it. Commercial listing data and clinical evidence remain separate.
different entity
Short-term tolerability was reported for full-length IV Tβ4, not TB-500 fragment.
fragment-specific regulatory
FDA lacks human exposure data and sufficient safety information for the TB-500 fragment.
| Evidence class | What the source supports |
|---|---|
| different entity | Short-term tolerability was reported for full-length IV Tβ4, not TB-500 fragment. |
| fragment-specific regulatory | FDA lacks human exposure data and sufficient safety information for the TB-500 fragment. |
Source-by-source evidence notes
These notes state what each inspected source can support and the boundary that should not be crossed when interpreting it.
Intravenous full-length thymosin beta-4 in healthy volunteers
Evidence class: primary randomized phase 1 entity mismatch. What it supports: Short-term tolerability and pharmacokinetics of characterized full-length thymosin beta-4 in healthy volunteers.
What it does not establish: TB-500 fragment identity, TB-500 safety, injury healing, retail-product quality, or a TB-500 dose.
FDA bulk substances that may present significant safety risks
Evidence class: primary regulatory. What it supports: FDA's BPC-157, injectable GHK-Cu, and TB-500 fragment safety/characterization statements; no identified human TB-500 fragment exposure data.
What it does not establish: A diagnosis, individual risk estimate, or claim that topical GHK-Cu and injectable GHK-Cu share one risk profile.
Full-length thymosin beta-4 ophthalmic solution phase 2 trial
Evidence class: primary randomized phase 2 entity and route mismatch. What it supports: 72-person ophthalmic full-length Tβ4 study; primary endpoints were not significant; selected secondary endpoints differed.
What it does not establish: TB-500 fragment efficacy, systemic administration, injury protocols, or retail-vial safety.
Questions this page answers
Did trials show TB-500 is safe?
No. The cited trials studied full-length Tβ4, not the fragment sold as TB-500.
Were there no adverse events in the dry-eye study?
That route-specific full-length study cannot establish systemic fragment safety, regardless of its reported events.
What remains unresolved
- No fragment-specific human safety database.
- No incidence estimates.
- No product-level adverse-event ledger.