TB-500
Also known as: Thymosin Beta-4 · Tβ4
Contents
MW
4963.44 Da
Amino Acids
43 AA
Half-Life
14 days (active metabolite)
Route
SubQ, IM
CAS
77591-33-4
Formula
C212H350N56O78S
Amino Acid Sequence
SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES
Mechanism of Action
TB-500 is the synthetic, injectable actin-binding fragment of Thymosin Beta-4 (Tβ4), corresponding to the 16-amino acid LKKTETQ-containing region responsible for Tβ4's biological activity. Unlike BPC-157 which acts locally at an injury site, TB-500 provides SYSTEMIC tissue repair — distributing throughout the body via circulation to address inflammation and healing at multiple sites simultaneously.
PRIMARY MECHANISM — G-ACTIN SEQUESTRATION: Binds G-actin (globular actin monomers), regulating actin polymerization dynamics. This directly controls cell migration — the fundamental process required for tissue repair. By modulating actin availability, TB-500 orchestrates coordinated movement of fibroblasts, endothelial cells, and immune cells to sites of damage.
SECONDARY MECHANISM — MRTF-A/SRF PATHWAY: The Tβ4-actin complex regulates MRTF-A (myocardin-related transcription factor A), which controls SRF (serum response factor) target genes. These genes include key repair proteins: smooth muscle actin, collagen, fibronectin, and VEGF. This pathway explains TB-500's broad systemic repair capacity.
ANGIOGENESIS: Upregulates VEGF systemically, promoting new blood vessel formation throughout the body — not just at one site. This explains improved circulation and healing in multiple simultaneous injury sites, which is a distinguishing feature vs. BPC-157.
ANTI-INFLAMMATORY: Inhibits NF-κB transcription factor, reducing systemic inflammatory cytokines (TNF-α, IL-6, IL-1β).
ECM REMODELING: Upregulates matrix metalloproteinases (MMPs) that clear damaged extracellular matrix, and promotes deposition of organized replacement collagen.
CARDIAC: Directly promotes cardiomyocyte survival after ischemia, activates cardiac progenitor cells, and reduces myocardial fibrosis.
HAIR: Promotes vascularization around hair follicles via VEGF, recruiting follicle stem cells and extending the anagen (growth) phase.
IMPORTANT DISTINCTION: TB-500 is the synthetic injectable fragment of Thymosin Beta-4 — it is NOT the same as full-length Tβ4.
Dosing Protocol
Low Dose
███ – ███ mcg/day
Standard Dose
███ mcg/day
High Dose
███ – ███ mcg/day
Dosing protocols are for paid members
Get exact dosing ranges, injection frequency, timing rationale, and reconstitution math.
Get Clinical Access — $79/moFrequency
LOADING PHASE (Weeks 1–6): Twice weekly — Monday and Thursday, or any 3–4 day split.
Half-Life
14 days (active metabolite)
Reconstitution Guide
Full reconstitution protocol with BAC water volumes, concentration math, and units-to-draw per dose is available on the Clinical plan.
Unlock reconstitution guide →Clinical Warnings
CRITICAL CANCER WARNING: Animal experiments demonstrated TB-500 accelerated dormant tumor growth. Absolute contraindication with any active, prior, or suspected malignancy.
WADA PROHIBITED.
NO HUMAN CLINICAL TRIALS.
IMMUNE DISRUPTION in animal models.
Full Tβ4 ≠ TB-500 — different molecules.
Contraindications
Absolute
Active cancer
Pregnancy
Relative Cautions
Autoimmune disease
History of cancer within 5 years
Side Effect Profile
Mild
- ●Injection site irritation
- ●Mild lethargy
- ●Head rush
Moderate
- ●Headache
- ●Temporary fatigue
Synergistic Peptides
Common Stacks
BPC-157
GHK-Cu
Research Status
PRECLINICAL ONLY — NO HUMAN CLINICAL TRIALS FOR TB-500. Full-length Tβ4 human data: corneal wound healing (Sosne et al.), cardiac repair (PHASER trial). TB-500 is a fragment — Tβ4 data does not directly transfer. Animal evidence strong across wound healing, cardiac repair, tendon, hair. CRITICAL: Animal studies showed acceleration of dormant tumor growth.
Frequently Asked Questions
How does TB-500 work?
TB-500 is the synthetic, injectable actin-binding fragment of Thymosin Beta-4 (Tβ4), corresponding to the 16-amino acid LKKTETQ-containing region responsible for Tβ4's biological activity. Unlike BPC-157 which acts locally at an injury site, TB-500 provides SYSTEMIC tissue repair — distributing throughout the body via circulation to address inflammation and healing at multiple sites simultaneously. PRIMARY MECHANISM — G-ACTIN SEQUESTRATION: Binds G-actin (globular actin monomers), regulating ac
What is the standard dose of TB-500?
TB-500 dosing protocols are available with a ClinPep Clinical subscription. Dosing varies by indication and patient factors — consult a licensed healthcare provider. General frequency: LOADING PHASE (Weeks 1–6): Twice weekly — Monday and Thursday, or any 3–4 day split.
What is the half-life of TB-500?
The half-life of TB-500 is 14 days (active metabolite). This determines optimal dosing frequency and timing.
Who should not use TB-500?
TB-500 is absolutely contraindicated in: Active cancer; Pregnancy. Use with caution in: Autoimmune disease; History of cancer within 5 years.
What are the side effects of TB-500?
Common mild side effects include: Injection site irritation, Mild lethargy, Head rush. Moderate effects: Headache, Temporary fatigue.
What peptides stack well with TB-500?
TB-500 is commonly stacked with: BPC-157, GHK-Cu, CJC-1295.
How do you reconstitute TB-500?
TB-500 is reconstituted with bacteriostatic water. Exact volumes, concentrations, and units-to-draw calculations are available in the ClinPep Clinical plan. Always follow your compounding pharmacy's instructions.
How long should you cycle TB-500?
TB-500 cycle protocols vary by indication. Detailed cycle length, on/off schedules, and monitoring guidelines are available with ClinPep Clinical access. Consult your healthcare provider for personalized cycling guidance.
References & Citations
10 PubMed studies · 3 clinical trials
Engineered Tandem Thymosin Peptide Promotes Corneal Wound Healing.
Nguyen Joseph, Verma Sudhir, Vuong Vivian T, Queener Hope et al.. Investigative ophthalmology & visual science. 2025
Thymosin beta-4 (TB4) is a small peptide upregulated in injured tissues, playing roles in cell migration, angiogenesis, inflammation, and oxidative stress. Studies show TB4 significantly promotes corn
Injectable Thymosin β4-Modified Hyaluronic Acid Hydrogel with Exosomes for Stem Cell Homing and Neuronic-Angiogenic-Osteogenic Coupled Cranial Repair.
Xi Yanhai, Zhang Zhen, Zhao Zixuan, Qiu Ba et al.. ACS nano. 2025
Accelerating angiogenesis, neurogenesis, and in situ stem cell recruitment at the site of bone defects is critical for bone regenerative repair. Bone marrow mesenchymal stem cell (BMSC) exosomes are c
Tβ4-Engineered ADSC Extracellular Vesicles Rescue Cell Senescence Through Separable Microneedle Patches for Diabetic Wound Healing.
Ding Youjun, Wang Jinglin, Li Jiaye, Cheng Yi et al.. Advanced science (Weinheim, Baden-Wurttemberg, Germany). 2025
Microneedles loaded with bioactive substances have demonstrated efficacy in wound healing, while their application in the elderly chronic wounds, aggravated by cellular senescence, is still a signific
Proteomic analysis of the human amniotic mesenchymal stromal cell secretome by integrated approaches via filter-aided sample preparation.
Muntiu Alexandra, Papait Andrea, Vincenzoni Federica, Rossetti Diana Valeria et al.. Journal of proteomics. 2025
The immunomodulatory, anti-inflammatory and regenerative properties of the human amniotic mesenchymal stromal cells (hAMSCs) secretome are acknowledged but the understanding of the specific bioactive
Activation of pro-resolving pathways mediate the therapeutic effects of thymosin beta-4 during Pseudomonas aeruginosa-induced keratitis.
Wang Yuxin, Banga Loveleen, Ebrahim Abdul Shukkur, Carion Thomas W et al.. Frontiers in immunology. 2024
Current treatments for bacterial keratitis fail to address the sight-threatening inflammatory host response. Our recent work elucidating the therapeutic mechanisms of adjunctive thymosin beta-4 (T
In Vitro Study of Thymosin Beta 4 Promoting Transplanted Fat Survival by Regulating Adipose-Derived Stem Cells.
Li Wandi, Yang Yan, Lin Yan, Mu Dali. Aesthetic plastic surgery. 2024
Autologous fat grafting (AFG) has emerged as a highly sought-after plastic surgery procedure, although its success has been hampered by the uncertain fat survival rate. Current evidence suggests that
A Novel Combination Therapy Tβ4/VIP Protects against Hyperglycemia-Induced Changes in Human Corneal Epithelial Cells.
Ebrahim Abdul Shukkur, Carion Thomas W, Ebrahim Thanzeela, Win Jeff et al.. Biosensors. 2023
Despite the prevalence of diabetic retinopathy, the majority of adult diabetic patients develop visually debilitating corneal complications, including impaired wound healing. Unfortunately, there is l
Thymosin beta-4 participate in antibacterial immunity and wound healing in black tiger shrimp, Penaeus monodon.
Lin Changhong, Qiu Lihua, Wang Pengfei, Zhang Bo et al.. Fish & shellfish immunology. 2023
Thymosin beta-4 (Tβ4) is a ubiquitous protein with multiple and diverse intracellular and extracellular functions in vertebrates, which play fundamental roles in innate immune against pathogens
Registered Clinical Trials
Safety and Efficacy Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction.Infarction
Study of Thymosin Beta 4 in Patients With Pressure Ulcers
Study of Thymosin Beta 4 in Patients With Venous Stasis Ulcers
Symptom Indications
Full Clinical Access
Complete TB-500 Protocol
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This information is for educational and research reference purposes only. ClinPep does not provide medical advice, diagnosis, or treatment recommendations. All protocols should be reviewed by a licensed healthcare provider.