TB-500 — Peptide Reference

01 — Identity

Name & Classification

TB-500 is a synthetic peptide corresponding to the actin-binding domain of Thymosin Beta-4 (Tβ4), specifically the fragment Ac-LKKTETQ (residues 17–23 of Tβ4). It is often used interchangeably with full-length Thymosin Beta-4, though TB-500 refers specifically to this active fragment.

Thymosin Beta-4 is a naturally occurring 43-amino acid protein present in virtually every cell of the human body and at particularly high concentrations in platelets and wound fluid. It is classified as an actin-sequestering peptide — it binds G-actin monomers, regulating the dynamic assembly and disassembly of actin filaments that govern cell migration, proliferation, and tissue repair.

Also known as: Tβ4 fragment | Thymosin β4 (17-23)

02 — Origin

When It Was Developed

1960s

Thymosin fraction 5 isolated from bovine thymus by Dr. Allan Goldstein at the Albert Einstein College of Medicine as part of thymus hormone research. Thymosin Beta-4 later identified as a key component.

1981

Thymosin Beta-4 fully sequenced and characterized. Identified as the most abundant intracellular peptide in mammalian cells — present at concentrations of 200–500 µM in platelets.

1990s–2000s

Role in wound healing, cell migration, and angiogenesis established. Research groups at RegeneRx Biopharmaceuticals began clinical development of full-length Tβ4 for corneal wound healing, dry eye, and cardiac repair.

2004–2012

The Ac-LKKTETQ fragment (TB-500) identified as the minimal sequence responsible for most of Tβ4's actin-binding, cell migration, and wound-healing activity. Began use as research peptide in veterinary and human performance contexts.

2010s–Present

Widely adopted in sports medicine and injury recovery for tendon, muscle, and ligament healing. Cardiac repair research ongoing — Tβ4 shown to reactivate dormant cardiac progenitor cells after myocardial infarction. No FDA approval as a drug; research peptide status.

03 — Research History

Research Background

TB-500's core mechanism centers on actin regulation. By sequestering G-actin monomers, it promotes the rapid migration of repair cells — keratinocytes, fibroblasts, endothelial cells — into wound sites. This is critical because tissue repair speed is largely limited by how fast cells can reach and fill the damaged area. TB-500 essentially removes the brake on cell migration.

Beyond its actin-binding role, TB-500 promotes angiogenesis (new blood vessel formation) in ischemic tissue, reduces inflammatory cytokines (particularly in cardiac tissue), and activates the PI3K/Akt survival pathway that protects cells from apoptosis in hypoxic conditions. This combination makes it particularly valuable for both acute injury and chronic ischemic conditions.

The cardiac research is especially compelling: studies in rodent myocardial infarction models showed that Tβ4/TB-500 reactivated epicardial progenitor cells that are normally dormant in adult hearts, prompting regeneration of cardiomyocytes. It also significantly reduced infarct scar size and preserved ejection fraction. Human cardiac trials are in early stages. Neurological research suggests TB-500 crosses the blood-brain barrier and promotes remyelination and neuronal survival after injury.

04 — Key Benefits

Proposed Benefits

Accelerates repair of tendons, ligaments, and muscle tissue

Promotes cell migration via actin-sequestering mechanism

Stimulates angiogenesis — new vessel formation in injured tissue

Reduces systemic inflammation and inflammatory cytokines

Cardiac protection — progenitor cell activation, scar reduction

Promotes flexibility — reduces connective tissue adhesions

Crosses blood-brain barrier — neuronal repair and remyelination

Activates PI3K/Akt pathway — cytoprotection in hypoxic conditions

Compatible with BPC-157 — synergistic injury healing combination

Systemic distribution — heals distant injuries from single injection site

05 — Reconstitution

10 mg Vial + 300 Units BAC Water

33.3 mcg

per unit drawn on insulin syringe

10,000

mcg total

0.3 mL

total volume

4–6 wk

shelf life (fridge)

Store refrigerated at 2–8°C after reconstitution. TB-500 is a relatively stable peptide in solution. Inject subcutaneously anywhere on the body — it distributes systemically and does not need to be injected near the injury site (unlike BPC-157 local protocols). Do not freeze reconstituted vial. Light-protect if storing for extended periods.

06 — Dosage

Dosage Reference

Dose	Units to Draw	Context
2.0 mg / injection	~60 u	LOW / INTRO
2.5 mg / injection	~75 u	COMMON
5.0 mg / injection	~150 u	STANDARD
7.5–10 mg / injection	~225–300 u	HIGH

TB-500 is typically dosed at 2–5 mg per injection, 2–3× per week during a loading phase, then reduced to weekly maintenance dosing. Unlike most peptides, the weekly or twice-weekly injection schedule reflects its longer systemic action. Higher single doses (5–10 mg) are used by some practitioners for acute injury recovery. 300 units on a U-100 syringe = 0.3 mL = the entire reconstituted vial volume.

07 — Monitoring

Biomarkers, Lab Tests & Ranges

TB-500 primarily impacts connective tissue repair, angiogenesis, inflammation, and cardiac markers. Monitor the following before, at 6 weeks, and at cycle end.

▸ Tissue Repair & Connective Tissue

Biomarker	Lab Test	Clinical Range	Optimal Range
IGF-1 Repair growth factor	Serum IGF-1	CLINICAL~115–355 ng/mL (adult)	OPTIMALUpper 1/3 for age (~200–300 ng/mL)
COMP Cartilage & tendon matrix turnover	Serum COMP	CLINICAL<12 U/L	OPTIMAL<8 U/L (stable or declining)
P1NP Collagen synthesis marker	Serum Procollagen Type I N-terminal	CLINICALM: 20–76 / F: 15–59 µg/L	OPTIMALUpper half of age range; trending up
VEGF Angiogenesis marker	Serum VEGF	CLINICAL62–707 pg/mL	OPTIMALMid-to-upper range during active healing

▸ Cardiac Health

Biomarker	Lab Test	Clinical Range	Optimal Range
NT-proBNP Cardiac wall stress marker	Serum NT-proBNP	CLINICAL<125 pg/mL (<75 yrs)	OPTIMAL<50 pg/mL
Troponin I / T	High-sensitivity Troponin	CLINICAL<0.04 ng/mL (standard)	OPTIMALUndetectable / baseline stable
hsCRP	High-sensitivity CRP	CLINICAL<3.0 mg/L	OPTIMAL<0.5 mg/L

▸ Inflammation & Immune

Biomarker	Lab Test	Clinical Range	Optimal Range
IL-6	Serum Interleukin-6	CLINICAL<7.0 pg/mL	OPTIMAL<1.5 pg/mL
TNF-α	Serum TNF-alpha	CLINICAL<8.1 pg/mL	OPTIMAL<2.0 pg/mL
WBC differential Immune activation check	CBC with differential	CLINICALWBC 4.5–11.0 × 10³/µL	OPTIMALWBC 4.5–6.0; neutrophil % 50–65%

▸ Safety Panel

Biomarker	Lab Test	Clinical Range	Optimal Range
AST / ALT	CMP	CLINICALAST 10–40 / ALT 7–56 U/L	OPTIMALAST <26 / ALT <26 U/L
Creatinine / eGFR	CMP	CLINICALCreat 0.7–1.3 / eGFR >60	OPTIMALCreat 0.8–1.1 / eGFR >90
CBC	Complete Blood Count	CLINICALStandard ranges	OPTIMALMid-range; WBC 4.5–6.0

⚠ TB-500 is not FDA-approved. No human clinical trials are published for this fragment specifically; data derives from Thymosin Beta-4 research and real-world use. One theoretical concern: TB-500 promotes angiogenesis (VEGF upregulation) — individuals with a history of cancer or pre-cancerous conditions should consult an oncologist before use, as pro-angiogenic peptides may promote tumor vascularity. All other users: standard monitoring applies.

08 — Cycle Protocol

Cycle Length, Frequency & Timing

▸ How Long to Cycle

ACUTE INJURY

6–8 Weeks

For acute injuries (tendon tears, muscle strains, ligament damage), a loading phase of 2× weekly for 4–6 weeks followed by 1× weekly maintenance is the standard approach.

LONGEVITY / PREVENTION

10–12 Weeks

For systemic anti-inflammatory, connective tissue maintenance, or cardiac support protocols, 10–12 week cycles at lower frequency with a 6–8 week break between cycles.

TB-500 is commonly paired with BPC-157 for injury recovery — the two peptides work via complementary, non-overlapping mechanisms. BPC-157 upregulates GH receptors and drives VEGF locally; TB-500 promotes systemic cell migration and angiogenesis. The combination is considered the most powerful injury recovery stack in the research peptide space.

▸ Frequency & Timing

Variable	Recommendation	Why
Loading Phase	2–3× / week for 4–6 wks	Higher frequency during loading ensures rapid saturation of systemic Tβ4 receptor sites and maximal cell migration signal during the acute healing window.
Maintenance Phase	1× / week	Once the acute phase resolves, weekly maintenance dosing sustains the angiogenic and anti-inflammatory signal at a lower dose burden. TB-500 has a longer effective action window than daily peptides.
Fasted vs Fed	~ Either acceptable	TB-500's mechanism is not insulin- or glucose-dependent. Food intake does not meaningfully affect its efficacy. AM fasted is conventional but not required for TB-500 specifically.
Injection site	✓ SC anywhere — distributes systemically	Unlike BPC-157, TB-500 does not need to be injected near the injury. It distributes systemically after any SC injection. Abdomen or thigh are standard sites.
Timing	AM preferred, any day	Morning dosing is conventional. Given the weekly/twice-weekly schedule, day of week matters less than consistency — inject on the same scheduled days each week.

PROTOCOL SUMMARY

6–12 wk

CYCLE LENGTH

2–3× → 1×

LOAD → MAINTAIN

AM

TIMING

Either

FED STATE

SC anywhere

INJECTION SITE

6–8 wk

BREAK