TB-500 (Thymosin Beta-4)
Also known as: Thymosin Beta-4, Thymosin β4, Thymosin Beta-4 Fragment, Ac-LKKTETQ, Tβ4, TB-4, Thymosin Beta-4 Fragment 17-23, Fequesetide, TB-500 (Ac-LKKTETQ)
Thymosin β4 · 43-amino-acid regenerative peptide
Overview
Naturally occurring 43-amino acid peptide crucial for tissue repair, wound healing, and cellular regeneration. Promotes angiogenesis, reduces inflammation, and supports cell migration and differentiation.
A note on the name. "TB-500" and "thymosin beta-4" are used interchangeably by sellers, but they are not always the same molecule. Thymosin β4 is the natural 43-amino-acid peptide, and most of the healing research — including the clinical programme — was run on it. "TB-500" originally named a synthetic 7-amino-acid fragment of that peptide (Ac-LKKTETQ, residues 17–23), which carries the same actin-binding site but is a much smaller molecule with a far thinner evidence base. Research-peptide suppliers sell both under the "TB-500" label and the vial rarely says which. This page describes the full-length 43-amino-acid peptide, because that is what the evidence is on. If a certificate of analysis gives a mass near 844 Da rather than ~4,963 Da, what you have is the heptapeptide fragment instead — the doses below were not derived from it.
Key benefits
- Superior systemic tissue repair
- Accelerated muscle, tendon, and ligament healing
- Enhanced cell migration and angiogenesis
- Comprehensive regenerative effects
- Neuroprotective properties
Mechanism of action
Acts as principal actin-sequestering protein, regulating cell migration, promoting angiogenesis, reducing inflammation, and activating stem cell differentiation for comprehensive regenerative effects.
Molecular data
- Type
- Thymosin peptide
- Half-life
- ~2 hours
Sequence
Ac-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
Indications
What the research community uses this compound for, with self-reported effectiveness.
Tissue Repair
Muscle Regeneration
Most effectiveAccelerated healing of muscle fibers with reduced recovery time and enhanced repair via cell migration and differentiation.
Tendon & Ligament Healing
Most effectiveConnective tissue repair with reduced scar formation and improved biomechanical properties of healing tissues.
Wound Healing
Most effectiveEnhanced dermal closure, improved angiogenesis, and reduced inflammation in acute and chronic scenarios.
Athletic Recovery
Exercise Recovery
EffectiveFaster recovery from intense training with reduced muscle soreness and improved tissue repair.
Injury Prevention
EffectiveStrengthened tissues through enhanced repair mechanisms may reduce injury risk.
Performance Enhancement
ModerateImproved muscle quality through enhanced regeneration and repair pathways.
Neurological
Neuroprotection
ModerateProtective effects against neuronal damage in various models.
Spinal Cord Injury Support
ModeratePreclinical evidence for improved outcomes in spinal injury models.
Brain Health
EmergingPotential neuroprotective and regenerative effects on brain tissue.
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Injectable
Subcutaneous or intramuscular injection. Flexible timing with no empty stomach requirement. Can be injected near injury site for localized effect.
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| General tissue repair | 2-3mg | 2x weekly | SubQ or IM |
| Serious injury recovery | 4-5mg | 3x weekly | SubQ near injury site |
| Athletic enhancement | 2-3mg | 2x weekly | SubQ |
| Chronic conditions | 3-4mg | 2-3x weekly | SubQ or IM |
| Maintenance | 2mg | 1-2x weekly | SubQ |
| Post-surgical recovery | 3-5mg | 3x weekly | SubQ |
Preparation
You will need
- Bacteriostatic water (BAC)
- Insulin syringes (1mL recommended)
- Alcohol swabs
- TB-500 vial (2mg or 5mg typical)
- Sterile work surface
Steps
- Clean work area and hands thoroughly with alcohol
- Calculate required BAC water volume
- Draw calculated BAC water slowly into syringe
- Inject BAC water slowly down vial side (never directly on powder)
- Gently swirl vial until powder completely dissolves
- Store reconstituted solution refrigerated, use within 28 days
Work out the water volume and syringe units in the reconstitution calculator →
Topical
Topical formulations available for specific applications including wound healing and eye conditions.
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| Chronic wound healing | 0.01-0.03% concentration | 1-2x daily | Topical application |
| Dry eye treatment | Eye drops formulation | As directed | Ophthalmic |
Interactions
Pairwise interactions with other compounds you might be cycling — the same data behind the cycle builder's safety check.
BPC-157
SynergisticComplementary healing mechanisms with enhanced tissue repair when combined (Wolverine Stack).
Ipamorelin
CompatibleMay enhance tissue sensitivity to growth hormone effects.
CJC-1295
SynergisticCombined tissue repair with GH-releasing effects for comprehensive recovery.
IGF-1
SynergisticEnhanced muscle and tissue regeneration through complementary growth pathways.
GHRP-6
CompatibleNo negative interactions; potential enhanced recovery.
Melanotan II
CompatibleDifferent receptor families with no pathway overlap.
Timeline
Typical week-by-week effects reported in clinical and observational data.
- Week 1-2
Reduced inflammation and improved tissue sensation
- Week 2-4
Accelerated healing rate and improved tissue quality
- Week 4-8
Maximum tissue repair and regenerative benefits
- Week 6-12
Continued improvement in tissue strength and function
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Generally minimal side effects
- Possible mild injection site reactions
- Temporary fatigue in some users
Stop signs — stop and seek advice
- Persistent or worsening injection site infections
- Unusual swelling or prolonged redness
- Severe allergic reactions
- Unexpected systemic symptoms
- Concerning health changes
Contraindications
- Active cancer treatment (due to angiogenic effects)
- Pregnancy or breastfeeding
- Immunosuppressive medications (consult provider)
- WADA prohibited for competitive athletes
Quality checks
What a legitimate product looks like, what should give pause, and what should make you stop.
Good signs
- White lyophilized powder - fine, evenly distributed with light fluffy texture
- Clear, colorless solution after reconstitution with no particles
- Proper vacuum seal intact with secure rubber stopper
Warning signs
- Slight powder clumping acceptable if completely dissolves with gentle swirling
Stop signs — don't use
- Colored or crystalline powder (yellow/brown indicates degradation)
- Persistent cloudiness, floating particles, or precipitation
- Damaged vial seal or contamination signs
Recent research
Newer papers and trial readouts on file for this compound, with source and date.
November 2025 · Investigative Ophthalmology & Visual Science
Engineered Tandem Thymosin Peptide Promotes Corneal Wound Healing
Engineered tandem thymosin beta-4 peptide showed superior bioactivity and enhanced corneal wound-healing efficacy over native TB4, with improved scalability via bacterial fermentation.
March 2023 · International Immunopharmacology
Thymosin beta-4 denotes new directions towards developing prosperous anti-aging regenerative therapies
Comprehensive review by Bock-Marquette et al. on thymosin beta-4's role in reversing aging processes and accelerating organ regeneration through reactivation of embryonic developmental programs.
May 2021 · Cells
Utilizing Developmentally Essential Secreted Peptides Such as Thymosin Beta-4 to Remind the Adult Organs of Their Embryonic State-New Directions in Anti-Aging Regenerative Therapies
Review of TB-500's ability to reactivate embryonic developmental processes in adult organs, promoting cell migration, stem cell mobilization, and tissue regeneration for anti-aging applications.
References
Primary literature and clinical-trial data informing this entry.
The regenerative peptide thymosin beta-4 accelerates the rate of dermal healing in preclinical animal models and in patients
Treadwell, T., Kleinman, H.K., Crockford, D., Hardy, M.A., Guarnera, G.T., Goldstein, A.L. · Annals of the New York Academy of Sciences · 2012
In two Phase 2 clinical trials, thymosin beta-4 accelerated healing of chronic pressure ulcers and venous stasis ulcers by almost a month compared to placebo, with confirmed safety and tolerability.
Development of thymosin beta4 for treatment of patients with ischemic heart disease
Crockford, D. · Annals of the New York Academy of Sciences · 2007
Synthetic thymosin beta-4 given intravenously was well tolerated with no dose-limiting toxicity; promotes cardiomyocyte migration and survival, and stimulates coronary vasculogenesis for cardiac ischemia treatment.
Evaluation of skeletal and cardiac muscle function after chronic administration of thymosin beta-4 in the dystrophin deficient mouse
Spurney, C.F., et al. · PLoS One · 2010
Chronic thymosin beta-4 administration increased the number of regenerating skeletal muscle fibers in exercised dystrophin-deficient (mdx) mice, showing potential for Duchenne muscular dystrophy treatment.
Thymosin beta-4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial
Sosne, G., Dunn, S.P., Kim, C. · Cornea · 2015
Phase 2 randomized trial in 9 severe dry eye patients showed RGN-259 (0.1% thymosin beta-4) eye drops achieved statistically significant improvements in both signs and symptoms, with effects lasting 28 days post-treatment.
A first-in-human, randomized, double-blind, single- and multiple-dose, phase I study of recombinant human thymosin beta-4 in healthy Chinese volunteers
Wang, X., et al. · Journal of Cellular and Molecular Medicine · 2021
Phase I study in 54 healthy subjects with ascending doses (0.05-25.0 mcg/kg) demonstrated mild to moderate adverse events with no dose-limiting toxicities or serious adverse events.
0.1% RGN-259 (Thymosin beta-4) Ophthalmic Solution Promotes Healing and Improves Comfort in Neurotrophic Keratopathy Patients in a Randomized, Placebo-Controlled, Double-Masked Phase III Clinical Trial
Sosne, G., Kleinman, H.K., Springs, C., Gross, R.H., Sung, J., Kang, S. · International Journal of Molecular Sciences · 2022
Phase III trial demonstrated thymosin beta-4 ophthalmic solution promotes corneal healing and improves comfort in neurotrophic keratopathy, advancing toward FDA approval.
Phase II Dry Eye Clinical Trial
2015
72 subjects showing significant positive effects on ocular discomfort and corneal staining with excellent safety profile.
Phase I Human Safety Study: Intravenous Thymosin β4
2010
First-in-human study establishing safety and pharmacokinetics in healthy volunteers with no dose-limiting toxicity.
Cardiac Protection Pilot Study: Thymosin β4 in STEMI Patients
2016
First human study in heart attack patients demonstrating potential clinical benefits in repairing damaged tissue.
Neurotrophic Keratopathy Compassionate Use Trial
2010
Complete clearing of persistent corneal defects in most subjects using topical formulation.
Synthesis and Characterization of N-terminal Acetylated 17-23 Fragment of Thymosin Beta-4
Drug Testing and Analysis · 2012
TB-500 contains Ac-LKKTETQ, the active site responsible for actin binding and wound healing.
Doping Control Analysis of TB-500
Journal of Chromatography B · 2012
TB-500 is a synthetic version of the active region of thymosin beta-4.
TB-500 Metabolism and Wound Healing
Journal of Chromatography B · 2024
TB-500 undergoes serial cleavage at C-terminus; acetylation protects N-terminus.
Investigation of TB-500 Metabolism
WADA · 2018
Characterized human metabolism of TB-500 using liver microsomes and S9 fraction.
Last updated . How this page was sourced is described in the methodology.
Featured in these stacks
- Classic Healing Stack (BPC-157 + TB-500)The best-known soft-tissue repair pairing — a cytoprotective peptide plus an actin-regulating one, for tendon, ligament, and muscle recovery.2 compounds
- Joint & Tendon RebuildA connective-tissue stack pairing BPC-157 and TB-500 with GHK-Cu for collagen-focused joint and tendon repair.3 compounds