Thymosin Beta-4 (Tβ4)

Evidence Anchor

BioHarmony 7.2/10

Thymosin beta-4 lands in the Worth trying band because it is the most clinically tested peptide in its class with a clean Phase 1 IV safety record, one Phase 3 primary-endpoint win, and broader mechanistic reach than its fragment cousin TB-500, yet it is hemmed in by Phase 3 misses in dry eye, a halted cardiac program, a closed US compounding path, and zero published human efficacy data for the off-label subcutaneous use case most buyers are interested in. The practical verdict splits by goal. For neurotrophic keratopathy patients with access to RGN-259 (currently trial-only), the human evidence is genuinely strong. For someone running an injury-recovery stack who can verify they have actual full-length Tβ4 rather than mislabeled fragment, the mechanism and safety floor make it a reasonable add. For general recovery or longevity goals it is mostly mechanism plus anecdote. The Worth trying score is honest because broader mechanism, better Phase 1 safety, and one Phase 3 win pull it above neutral, while Phase 3 endpoint misses and access friction keep it below Strong recommend. Among gray-market repair peptides, native Tβ4 stands out for having actual Phase 1 IV safety data in healthy volunteers, with no dose-limiting toxicity up to 1,260 mg per day for 14 days. That is the cleanest human safety floor in this peptide class.Ruff 2010, Ann NY Acad Sci✅ Best for: People recovering from a stubborn soft-tissue injury who want to add or substitute Tβ4 into a Wolverine-style BPC-157 stack for broader, less potent repair coverage than TB-500 alone. People with neurotrophic keratopathy who can access RGN-259 through a clinical trial, where SEER-1 Phase 3 hit on healing and comfort, per Sosne 2023. People with chronic poorly-healing wounds who are willing to work with a clinician and accept partial efficacy evidence. Research-minded users who can verify their material is genuine full-length Tβ4 with a certificate of analysis and third-party sequence confirmation, and who can monitor inflammation and tissue endpoints over a course. People who value the clean Phase 1 IV safety record and want the most clinically validated peptide in this class. ❌ Avoid if: You have active or recent (within 5 years) cancer, since preclinical metastasis and angiogenesis signals are real and human IHC data correlate Tβ4 expression with worse cancer outcomes, per Cha 2003 and Oh 2016. You are pregnant, breastfeeding, or considering it for a child, where no human safety data exists. You are a tested athlete subject to WADA prohibition, which bans Tβ4 and its derivatives at all times with a 30 to 45 day detection window. You cannot verify your material is genuine 43-amino-acid Tβ4 rather than the TB-500 fragment, which is what most gray-market vials actually contain. You want general anti-aging or cognitive benefits, which the human trials never tested. You want an approved, regulated, pharmaceutical-grade option, which Tβ4 is not anywhere in the world.

Read the full BioHarmony report

My score and my verdict: one signal of three, never the whole answer.