TB-500
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Synthetic fragment of Thymosin Beta-4; G-actin sequestration peptide promoting cell migration, angiogenesis, and anti-fibrotic tissue repair
Quick Facts
| Property | Value |
|---|---|
| Also Known As | Thymosin Beta-4 fragment, Tβ4, Ac-LKKTETQ |
| Category | Recovery / Anti-Aging / Wound Healing |
| Sequence | Ac-LKKTETQ (7 amino acids; active fragment of 43-aa Thymosin Beta-4) |
| Molecular Weight | ~889 Da (fragment); ~4963.5 Da (full-length Tβ4) |
| Molecular Formula | C₃₈H₆₇N₉O₁₃ (fragment) |
| PubChem CID | 16132341 |
| Administration | SubQ / IV / Topical |
| Typical Dose Range | 2.0–2.5 mg SubQ 2x/week (loading), 1x/week-biweekly (maintenance) |
| Half-Life | ~2–3 hours (plasma) |
| Storage | Lyophilized: -20°C, stable 24 months; Reconstituted: 2–8°C, use within 14–28 days |
| FDA Status | Research-only; not FDA-approved; reclassified as biologic. RGN-259 (Tβ4 eye drops) advanced to Phase 3 for dry eye/neurotrophic keratopathy |
| WADA Status | Prohibited under S0 (Non-Approved Substances) |
Mechanism of Action
TB-500 is the active fragment of Thymosin Beta-4 (Tβ4), the most abundant beta-thymosin in human cells, comprising 70-80% of all beta-thymosins. Its primary mechanism is G-actin sequestration via the WH2 domain, maintaining a ready pool of unpolymerized actin monomers for rapid filament assembly during cell migration. This drives fibroblast, keratinocyte, and endothelial cell movement to injury sites via filopodia and lamellipodia formation (PMID-36464872).
TB-500 activates the ILK-PINCH-Akt survival pathway, providing anti-apoptotic signaling through Caspase-3 inhibition. This is the key mechanism for cardioprotection — Tβ4 reduces infarct volume, prevents cardiac rupture post-MI, and preserves left ventricular function. It also activates epicardial progenitor cells, recapitulating developmental cardiac repair programs (PMID-25015963, PMID-27450736).
TB-500 stabilizes HIF-1α under normoxic conditions, upregulating VEGF and promoting angiogenesis independently of hypoxia. It also inhibits NF-κB, suppressing TNF-α, IL-1β, and IL-8 inflammatory cascades. Its metabolite Ac-SDKP exerts anti-fibrotic effects by inhibiting TGF-β signaling and preventing myofibroblast differentiation, reducing scar formation during healing (PMID-34992578).
Tβ4 operates through multiple signaling pathways including NF-κB, PI3K/Akt/eNOS, Notch, TGF-β, and Wnt pathways, making it one of the most multi-modal tissue repair peptides known. It also promotes hair follicle stem cell migration and differentiation, establishing a direct role in hair growth biology (PMID-17947589).
Key Research Areas
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Wound Healing — The foundational Malinda et al. (1999) study demonstrated topical Tβ4 increased re-epithelialization by 42-61% in rat dermal wounds, with enhanced angiogenesis and collagen deposition (PMID-10469335). Corneal wound healing and anti-inflammatory properties are well documented (PMID-19668473).
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Cardiac Repair — Peng et al. (2014) showed Tβ4 prevents cardiac rupture and improves cardiac function post-MI in mice, with reduced inflammation, decreased infarct size, and enhanced capillary density (PMID-25015963). Pipes (2016) reviewed the full cardioprotective evidence including epicardial progenitor cell activation (PMID-27450736).
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Ocular Applications (Clinical Trials) — RGN-259 (Tβ4 eye drops) advanced to Phase 3 clinical trials for dry eye and neurotrophic keratopathy, representing the most advanced clinical development of any Tβ4 formulation (PMID-30063853).
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Hair Growth — Philp et al. (2007) demonstrated Tβ4 promotes hair growth in rodent models by stimulating hair follicle stem cell migration from the bulge region (PMID-17947589).
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Anti-Aging and Regeneration — Bock-Marquette et al. (2023) reviewed Tβ4's potential as an anti-aging regenerative therapy, proposing that postnatal administration of developmental peptides may reverse aging processes (PMID-36709593).
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Anti-Infection — Tβ4 participates in antibacterial immunity across multiple species and tissue types (PMID-37018981, PMID-37689229).
Evidence Level Summary
| Evidence Type | Count | Notes |
|---|---|---|
| Human clinical trials | 0 direct | Phase 3 trials for RGN-259 (Tβ4 eye drops) reviewed in PMID-30063853 |
| Animal in vivo | 5 | Wound healing, cardiac repair, hair growth, antibacterial |
| In vitro | 0 | — |
| Narrative reviews | 8 | Mechanism, cardiac, ocular, anti-aging, functions overview |
| Total vault studies | 13 |
The evidence base for TB-500 is extensive preclinically but limited clinically. No human RCTs exist for systemic TB-500 injection. The closest clinical data comes from Phase 2/3 trials of RGN-259 (topical Tβ4 eye drops) for ophthalmological indications. Phase 1 IV safety data showed no drug-related serious adverse events at doses up to 1260 mg. Cardiac repair and wound healing data is robust in animal models across multiple research groups (not single-group dependent).
Clinical Applications
- Tendon and Ligament Repair — Promotes cell migration and collagen remodeling at injury sites
- Muscle Tears — Actin-mediated cell migration and anti-fibrotic healing
- Wound Healing — 42-61% improvement in re-epithelialization in preclinical models
- Injury Recovery — Broad musculoskeletal healing via systemic cell recruitment
- Stroke Recovery — Neuroprotective and angiogenic properties (preclinical)
- Post-Procedure Recovery — Anti-inflammatory and anti-scarring properties
- Hair Growth — Stem cell migration and differentiation in hair follicles
- Autoimmune Conditions — NF-κB inhibition and anti-inflammatory cascade
- Cardiac Health — Cardioprotection, infarct reduction, epicardial progenitor activation
Protocols Using This Peptide
- Wolverine Stack Protocol — Core peptide (paired with BPC-157 and MGF)
- Recovery Stack Protocol — Core systemic recovery peptide
- Post-Stroke Recovery Protocol — Adjunct for neuroprotection and angiogenesis
Ageless Peps Products
- AP-TB500-Vial — TB-500 Vial, variable sizes, $65 retail (currently out of stock)
- AP-TB500-500MCG-Capsules — TB-500 Capsules, 500mcg x 60 caps, $164 retail
- AP-BPC157-TB500-Blend — BPC-157/TB-500 Blend Vial, from $65 retail
- AP-WOLVERINE-Blend — WOLVERINE Blend (BPC-157 + TB-500 + MGF), $109 retail
- AP-GLOW-Blend — GLOW Blend (GHK-Cu + TB-500 + BPC-157), from $134 retail
- AP-KLOW-Blend — KLOW Blend (GHK-Cu + TB-500 + BPC-157 + KPV), $153 retail
- AP-BPC157-TB500-Capsules — BPC-157/TB-500 Capsules, $284 retail
- AP-Sample-Pack — Sample Pack (GLP-3 + BPC-157 + TB-500), $165 retail
Dosing Reference
Research Dosing Ranges
| Route | Dose Range | Frequency | Duration | Source |
|---|---|---|---|---|
| SubQ | 2.0–2.5 mg | 2x/week (loading) | 4–6 weeks | Practitioner guides |
| SubQ | 2.0–2.5 mg | 1x/week-biweekly (maintenance) | Ongoing | Practitioner guides |
| IV | Up to 1260 mg (Phase 1 safety) | Single dose | Phase 1 only | Phase 1 safety data |
| Topical (eye drops) | RGN-259 formulation | Multiple daily | Phase 3 trials | PMID-30063853 – Thymosin beta 4 and the eye bench to bedside |
Cycling
Standard cycling: 6 weeks on, 4 weeks off. Loading at 2x/week transitioning to maintenance at 1x/week or biweekly. No formal cycling protocol in peer-reviewed literature; guidance from practitioner consensus.
Contraindications & Safety
- Contraindications: Active malignancy (absolute — TB-500 promotes epithelial-mesenchymal transition which can facilitate metastasis). Proliferative retinopathy (risk of pathological neovascularization). Concurrent chemotherapy (protects cancer cells from apoptosis via Akt pathway).
- Common side effects: Mild injection site reactions, transient lethargy, headaches
- Drug interactions: Theoretical interaction with chemotherapeutic agents (anti-apoptotic effect may reduce efficacy). Caution with anticoagulants (angiogenesis promotion).
- Pregnancy/nursing: Not recommended; no safety data
- Special populations: Phase 1 IV safety: no drug-related serious adverse events at doses up to 1260 mg IV. No systematic data on renal, hepatic, or geriatric populations.
Safety profile based on Phase 1 IV data and extensive preclinical use. No completed Phase 2/3 systemic safety trials. RGN-259 Phase 3 trials (topical ocular) provide the most advanced clinical safety data for Tβ4.
Cancer Considerations
CONTRAINDICATED in active malignancy. TB-500 promotes epithelial-mesenchymal transition (EMT) which can facilitate metastasis, and protects cells from apoptosis via the ILK-PINCH-Akt pathway — which may inadvertently protect cancer cells from programmed death. Both mechanisms make TB-500 dangerous in cancer contexts. See Compliance / Cancer Safety Matrix for full ratings.
Synergistic Combinations
- BPC-157 + TB-500 — Complementary dual-mechanism: BPC-157 drives local angiogenesis while TB-500 provides systemic cell migration. Used in Wolverine Stack Protocol
- GHK-Cu + TB-500 — Multi-peptide healing: GHK-Cu adds copper-dependent collagen remodeling. Used in GLOW blend
- KPV + TB-500 — Anti-inflammatory synergy: KPV provides melanocortin NF-κB suppression. Used in KLOW blend
- PEG-MGF + TB-500 — Muscle repair: MGF activates satellite cells while TB-500 provides cell migration. Used in WOLVERINE blend
Related Research
| PMID | Title | Year | Study Type |
|---|---|---|---|
| PMID-10469335 | Thymosin beta4 accelerates wound healing | 1999 | Animal in vivo |
| PMID-17468232 | beta-Thymosins: small acidic peptides with multiple functions | 2007 | Narrative Review |
| PMID-17947589 | Tβ4 induces hair growth via stem cell migration | 2007 | Animal in vivo |
| PMID-19668473 | Tβ4: corneal wound healing and anti-inflammatory agent | 2009 | Narrative Review |
| PMID-25015963 | Tβ4 prevents cardiac rupture post-MI | 2014 | Animal in vivo |
| PMID-27450736 | Cardioprotection by Thymosin Beta 4 | 2016 | Narrative Review |
| PMID-30063853 | Tβ4 and the eye: bench to bedside (Phase 3 trials) | 2018 | Narrative Review |
| PMID-34992578 | Progress on Function and Application of Tβ4 | 2021 | Narrative Review |
| PMID-36464872 | Tβ4 and Actin: Binding Modes, Functions, Applications | 2023 | Narrative Review |
| PMID-36709593 | Tβ4: anti-aging regenerative therapies | 2023 | Narrative Review |
| PMID-37018981 | Tβ4: adjunct treatment for bacterial infections | 2023 | Narrative Review |
| PMID-37689229 | Tβ4 in antibacterial immunity and wound healing | 2023 | Animal in vivo |
| PMID-38706788 | Tβ4: healing middle ear lesions | 2024 | Narrative Review |
Related
#peptide #recovery #anti-aging #cosmetic #subq #iv #topical