TB-500
Also known as: Thymosin Beta-4, TB4, Timbetasin
Grey-Market Compound. This compound is not approved by the FDA or any major regulatory authority. No established regimen exists. Products available outside of regulated channels lack standardized manufacturing, quality control, and potency verification. Consult a qualified clinician. Research-only risks apply.
Overview
Clinical Summary
TB-500 is a synthetic version of the naturally occurring peptide thymosin beta-4 (TB4). Thymosin beta-4 is a 43-amino acid peptide found in virtually all human cells and plays a key role in tissue repair, cell migration, and anti-inflammatory responses. While preclinical evidence for wound healing and tissue repair is substantial, human clinical data are limited primarily to ophthalmic and dermal wound applications. TB-500 is widely used in the grey market for sports injury recovery.
Plain Language Summary
TB-500 is a synthetic form of thymosin beta-4, a natural peptide your body already makes. It plays a role in healing wounds and reducing inflammation. Animal studies show it can speed up healing of muscles, tendons, and skin. Some human studies exist for eye and skin wound healing, but there is limited clinical evidence for the musculoskeletal uses that make it popular. It is not an approved medication.
Mechanism of Action
Thymosin beta-4 sequesters monomeric G-actin, regulating actin polymerization and thereby influencing cell migration, proliferation, and differentiation. It promotes angiogenesis, reduces inflammation by downregulating pro-inflammatory cytokines, and supports stem cell migration to injury sites. The peptide upregulates laminin-5, a cell adhesion molecule involved in wound repair. In cardiac tissue, it has been shown to activate the Akt survival pathway and promote cardiomyocyte survival after ischemic injury.
Evidence Summary
Preclinical studies demonstrate accelerated wound closure, reduced fibrosis, improved cardiac function post-myocardial infarction, and enhanced tendon repair in rodent models. Human data include Phase 2 trials for corneal wound healing (RegeneRx Biopharmaceuticals) showing improved outcomes in neurotrophic keratitis. A small study in venous stasis ulcers showed improved healing rates. No completed RCTs exist for musculoskeletal indications in humans. The peptide has been studied in equine veterinary medicine for tendon injury with positive results.
Safety Profile
Thymosin beta-4 has been generally well tolerated in clinical trials for ophthalmic and dermal applications. No serious adverse events were attributed to the peptide in published trials. Theoretical concerns include potential tumor promotion (thymosin beta-4 is overexpressed in some cancers, though a causal role in oncogenesis is debated). Grey-market preparations introduce purity and dosing uncertainty.
Contraindications
- Known hypersensitivity
- Active malignancy (theoretical concern)
- Pregnancy and breastfeeding (no safety data)
Adverse Events
- Injection site reactions (mild, anecdotal)
- Headache (rare, anecdotal)
- Fatigue (rare, anecdotal)
- No systematic safety data for subcutaneous use
Interactions
- No formal drug interaction studies
- Theoretical concern with immunosuppressants (immunomodulatory properties)
Regulatory Notes
TB-500 / thymosin beta-4 is not FDA-approved for any indication. RegeneRx Biopharmaceuticals has pursued clinical development for ophthalmic indications. Grey-market TB-500 is sold as a research chemical and is not manufactured under GMP. It appears on WADA's prohibited substance list for athletes.
Monitoring Considerations
No established monitoring protocols. Monitor the target injury or condition. Given the relationship between thymosin beta-4 and cell proliferation, awareness of unusual growths may be prudent in a general sense, though no causal link to cancer has been established.
These are general considerations for clinical awareness and do not constitute prescriptive monitoring recommendations for any individual patient.
Stability and Handling Notes
Peptide stability is dependent on storage conditions. Grey-market products lack standardized stability testing. Lyophilized forms are generally more stable than reconstituted solutions.
References
- 1preclinical
Thymosin Beta 4 Promotes Cardiac Cell Migration, Survival, and Cardiac Repair
Bock-Marquette I, Saxena A, White MD, et al. (2004). Nature
Key findings: Demonstrated that thymosin beta-4 promotes cardiac cell survival via Akt activation and enhances cardiac repair after myocardial infarction in mice.
Limitations: Mouse model; human cardiac applications not validated.
View source - 2RCT
Thymosin Beta-4 for Neurotrophic Keratitis: Phase 2 Clinical Trial
Dunn SP, Heidemann DG, Chow CY, et al. (2010). Cornea
Key findings: Topical thymosin beta-4 (RGN-259) improved corneal wound healing in patients with neurotrophic keratitis.
Limitations: Small sample size. Ophthalmic application only.
- 3review
Thymosin Beta-4: A Multi-functional Regenerative Peptide
Goldstein AL, Hannappel E, Kleinman HK. (2005). Expert Opinion on Biological Therapy
Key findings: Review of thymosin beta-4 biology, tissue repair mechanisms, and clinical development pipeline.
Limitations: Review by the original discoverer; potential conflict of interest.
Last reviewed: 2024-11-15 | Version: 1 | Status: Published
More in Recovery
BPC-157
Body Protection Compound-157 · Bepecin · PL 14736 · PL-10
BPC-157 is a lab-made peptide based on a protein found naturally in stomach acid. In animal studies, it has shown remarkable healing properties for muscles, tendons, ligaments, the gut lining, and other tissues. However, there are very few human studies, so we do not know for certain whether these effects translate to people. It is popular among athletes and biohackers but is not an approved medication anywhere.
GHK-Cu
Copper Peptide GHK · Glycyl-L-histidyl-L-lysine:copper(II)
GHK-Cu is a small peptide naturally present in your blood that binds to copper. It decreases as you age. Research suggests it plays a role in wound healing, collagen production, and skin repair. It is commonly found in anti-aging skincare products. Some people use injectable forms for broader anti-aging or recovery purposes, but clinical evidence for injectable use is limited.
KPV
Lys-Pro-Val · alpha-MSH(11-13) · alpha-MSH C-terminal tripeptide
KPV is a small fragment of a natural hormone called alpha-MSH that helps control inflammation in the body. Researchers are interested in it because animal studies suggest it can reduce gut inflammation and may help with skin conditions. It has not been tested in human clinical trials, so its safety and effectiveness in people are not established. It is currently available only through unregulated sources.
Want to discuss this compound with a qualified physician?
The Peptide Association has verified over 160 licensed providers specializing in peptide therapy, with telehealth options available in most states.
Find a Verified Provider