TB-500 [TB4] (10mg)

CAS Number: 77591-33-4

Molecular Formula: C₂₁₂H₃₅₀N₅₆O₇₈S

Molecular Weight: 4963.44 g/mol

Sequence: Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser (43 amino acids)

What is TB-500/Thymosin βeta-4 (43aa)?

TB-500 (Thymosin Beta-4 acetate) is a synthetic 43-amino acid peptide derived from the naturally occurring thymosin beta-4 protein. It was originally identified in the thymus gland and is one of the most abundant intracellular proteins in mammalian cells. Paragonsportsmedicine Of the 16 known beta-thymosin family members, thymosin β4 is found in humans alongside thymosin β10 and β15. It is regarded as the main G-actin sequestering peptide and is present in all tissues and cell types except red blood cells. American Academy of Anti Aging Medicine

Primary Mechanism

The primary function of thymosin beta-4 is cell repair and regeneration, and it exhibits most of its actions through the sequestering of actin — essentially keeping actin in place at injury sites and signaling a cascade of repair reactions. Because actin is a key component of connective tissue, this action helps promote connective tissue healing. It also signals the body to migrate stem or progenitor cells to the site of damage, which then differentiate into myocytes, epithelial cells, or other connective/vascular cells to rebuild tissue. Peptides.org

Key Biological Activities

After injury, thymosin β4 is released by platelets, macrophages, and many other cell types to protect cells and tissues from further damage, reduce apoptosis, inflammation, and microbial growth. It also decreases the number of myofibroblasts in wounds, resulting in reduced scar formation and fibrosis. PubMed

Across preclinical systems, TB-500-associated readouts have been reported alongside changes in angiogenic transcriptional programs (including VEGF-related signaling), ECM remodeling markers, and stress-response pathways. PeptideSciences

TB-500 vs. Full-Length Thymosin Beta-4

TB-500 is a synthetic fragment corresponding to the actin-binding motif found within thymosin beta-4. As a result, it is discussed in research contexts focused on actin-related behavior while lacking additional regions present in the full-length peptide that may contribute to broader domain-dependent interactions. Because peptide naming is inconsistently used across secondary sources, sequence verification is recommended when comparing experimental findings. PeptideSciences

Areas of Active Research:

1. Wound Healing & Dermal Repair 🩹

Tβ4 has been shown to accelerate dermal healing of full-thickness wounds in multiple animal models, including normal rats, steroid-treated rats, diabetic mice, and aged mice. In two Phase 2 clinical trials involving stasis and pressure ulcers, it was found to accelerate healing by nearly a month in patients who did heal. It is thought to act by promoting cell migration and stem cell mobilization, while inhibiting inflammation, apoptosis, and infection. PubMed

In one rat wound model, topical or intraperitoneal administration of Tβ4 increased re-epithelialization by 42% at day 4 and as much as 61% by day 7 post-wounding, with treated wounds contracting at least 11% more than controls. Increased collagen deposition and angiogenesis were also observed. PubMed

2. Cardiovascular / Cardiac Repair ❤️

In experimental models, Thymosin Beta-4 reduced scar formation and improved heart function by limiting inflammation and supporting new vessel growth after events such as myocardial infarction. It encourages cardiac cell migration and epicardial progenitor mobilization, which aid in regenerating damaged heart tissue. Age Well ATL

Researchers have proposed that Tβ4, a peptide expressed during embryonic heart development, could be a powerful tool to increase regeneration and reverse aging-related processes in the heart via systemic administration. PubMed Central

3. Neurological & CNS Recovery 🧠

Tβ4 has shown great potential to promote CNS plasticity and nerve cell regeneration. It can target multiple nerve cell types — including neurons, oligodendrocytes, and microglia — in animal models of nerve injury, providing neuroprotection, immunosuppression, myelin sheath regeneration, synapse formation, and axonal growth. PeptideSciences

Tβ4 is expressed in most neural cell types of the developing brain and is upregulated in pathological conditions such as focal ischemia, Alzheimer’s disease, Huntington’s disease, hippocampal denervation, and seizure activity. Its presence in the nervous system likely plays a role in neuroprotection, synaptogenesis, and axon growth. American Academy of Anti Aging Medicine

4. Ocular / Eye Health 👁️

In the cornea, Tβ4 promotes cell migration and wound healing, has anti-inflammatory properties, and suppresses apoptosis. It has demonstrated potent wound healing and anti-inflammatory effects in numerous models of corneal injury, including suppression of the NF-κB transcription factor — a key mediator of inflammation. PubMed

Research suggests Tβ4 can elicit rapid corneal re-epithelialization and a reduction in corneal inflammation, offering promise for treating conditions ranging from minor injuries to severe inflammatory corneal pathologies and neurotrophic keratopathy. ScienceDirect

5. Musculoskeletal & Tissue Regeneration 🦴

Tβ4 has been studied in animal experiments and clinical trials for applications including myocardial infarction, liver and renal fibrosis, ulcerative colitis, colon cancer, and skin trauma, demonstrating its multifunctional involvement in proliferation, angiogenesis, and anti-apoptotic activity. PubMed Central

Tβ4 also decreases the number of myofibroblasts in wounds, resulting in decreased scar formation and fibrosis — a particularly significant property in musculoskeletal recovery. PubMed

6. Hair Growth 💇

Research using transgenic mice over-expressing Thymosin Beta-4 found that hair growth was accelerated, with especially high expression observed around hair follicles. This was associated with upregulation of laminin-5 in the skin, suggesting an important physiological role for Tβ4 in hair follicle activity. PubMed

7. Anti-Inflammatory & Immune Modulation 🔥

Thymosin Beta-4 demonstrates strong anti-inflammatory activity by regulating immune responses, lowering inflammatory cytokines such as TNF-α, and reducing NF-κB activation — key drivers of chronic inflammation. It also reduces oxidative stress, which further protects cells from damage during the inflammatory response. Age Well ATL

There has been strong research interest in Tβ4’s immune-modulating effects in autoimmune conditions, including experimental models of autoimmune encephalomyelitis, where it reduced inflammatory infiltrates and showed potential as a therapy relevant to multiple sclerosis. Medicalantiaging

Regulatory Status

TB-500 is not approved for human therapeutic use in any indication. It is classified as a Category 2 bulk drug substance per 2023 FDA guidance, prohibited for commercial pharmaceutical compounding. It is also banned under WADA’s S0 (Non-Approved Substances) category and is subject to anti-doping enforcement in competitive sports. Paragonsportsmedicine