TB-500

Overview

[educational] Important distinction: TB4 (thymosin β4) is the full 43-aa peptide; TB500 is only its 7-aa actin-binding fragment (LKKTETQ). They are not the same — TB4 has many more active sites (anti-inflammatory/anti-scar first 4 aa; anti-apoptotic first 15 aa; antimicrobial; signaling), so TB4 studies don’t translate 1:1 and TB4 is the preferred, better-studied one. A beta-thymosin (structure/repair), distinct from alpha-thymosins like Thymosin Alpha-1. — TB500 deep dive

[literature-animal] Promotes stem-cell proliferation, extracellular-matrix growth, and broad cell-type infiltration for wound repair (vs BPC-157’s vascular focus); animal data, no human trials. — Huberman 00:36–00:39
[educational] Human (TB4): skin wounds (phase-2, ~1 mo faster), eye/cornea (phase-3, 60% vs 13% healing), heart (TB4-pretreated stem cells +50% function). Animal: fracture (+25% stiffer), muscle repair 2–3× (dose-dependent), stroke/TBI functional recovery. Strong human safety data (IV up to 1,260 mg/day ×14 d) but no long-term post-course data. — TB500 deep dive
[literature] First registered TB-500-fragment human trial (2026): NCT07487363 — Phase 1/2 of the TB4 17–23 fragment vs placebo (3 dose cohorts, 8-wk dosing) for cardiovascular biomarkers in stable ASCVD. Safety-focused, no results; tests the fragment, not full-length TB4. — SOURCE-tb500-ascvd-rct-nct07487363

[anecdote] Not growth-promoting — does not act on the GH pathway (corrects a common misconception); often combined with BPC-157. — Huberman 00:39–00:40
[anecdote] Thymosin β4 (43 aa) acts on the actin cytoskeleton → cell migration; part of the thymic ‘fraction 5’ family (Goldstein lab); common horse-racing doping agent; the BPC-157 pairing is the ‘Wolverine stack’. — Bakri 01:38–01:52
[anecdote-bb] A-tier (healing) alongside BPC-157; its ~5 human-relevant studies reportedly show healing ≈ full-length thymosin β4 (so compounders often use β4 itself). — Anabolic Roundtable ~01:20

[protocol] SubQ (no oral — not acid-resistant like BPC; topical 0.03% gel for skin, 0.1% drops for eye). Hypothetical MSK dose ~500 mcg/day (up to 1 mg), anchored to human IV-safety data. TB4 daily (t½ ~1.5 h); TB500 can be 2–3×/week (longer t½). Cycle 4–6 wk on / ≥6 wk off (shorter than BPC). — TB500 deep dive

[warning] Cancer-risk framing slightly higher than BPC-157 — repair mechanisms (angiogenesis, cell migration/EMT → metastasis, anti-apoptosis, anti-ferroptosis) could feed existing cancer. Avoid with cancer history/family/precancerous; screen before use; short-term targeted use only. Verify product is full 43-aa TB4, not TB500 mislabeled (HPLC/MS). — TB500 deep dive
[regulatory] US status shifting (2026): TB-500 was removed from FDA Category 2 (Feb 2026) and is on the FDA PCAC 503A agenda for July 23 2026 — FDA’s evaluated use is wound healing. Advisory/non-binding; the FDA briefing doc reviews the TB-500 substance (the fragment), separate from full-length TB4. Not FDA-approved; still WADA-banned. — SOURCE-fda-pcac-503a-peptide-review-2026