Thymosin beta-4 fragment · Fact sheet
TB-500
Also known as Ac-LKKTETQ · Thymosin beta-4 fragment 17–23
TB-500 commonly refers to an acetylated seven-amino-acid fragment of thymosin beta-4. Human studies of the full-length peptide do not establish that this fragment heals tendons or injuries.
What is TB-500?
Analytical studies identified Ac-LKKTETQ in material labeled TB-500. The name is also applied inconsistently to full-length thymosin beta-4.
This entry concerns the fragment; the full-length 43-amino-acid peptide has a separate fact sheet.
Benefits & claims
Interest centers on actin binding, cell movement and tissue repair. These biological ideas do not establish a clinical recovery benefit.
What the evidence supports
- Mass-spectrometry studies distinguish the acetylated fragment from its parent protein.
- A study detecting the peptide in horses establishes analytical exposure, not therapeutic efficacy.
- Evidence from full-length thymosin beta-4 cannot be assigned automatically to TB-500.
Research areas
- Tissue-repair mechanisms
- Analytical identification
- Fragment metabolism
Dosage & frequency
No established human regimenThe reviewed sources do not establish a human treatment amount or frequency for TB-500. Animal and laboratory exposures are not human regimens.
How to read these amounts
An approved regimen belongs to a specific product, indication, and population. A study regimen describes what researchers tested; it does not establish a prescription or a safe self-use protocol. Products, routes, and formulations are not interchangeable. A prescriber uses the full label and individual clinical circumstances.
Personal accounts may describe amounts, schedules and outcomes beyond clinical research. They do not establish a regimen. Read the reported experiences
Formulations, interactions & practical context
- Identity and pharmacology
- Analytical studies identified Ac-LKKTETQ in material labeled TB-500. The name is also applied inconsistently to full-length thymosin beta-4.
Formulation differences
- This entry concerns the fragment; the full-length 43-amino-acid peptide has a separate fact sheet.
Interactions & precautions
- The reviewed sources do not establish a comprehensive human interaction profile for this exact substance or combination.
What is still unresolved
- Reliable human tendon-healing outcomes
- Exact identity of products using the TB-500 name
- Repeated-use safety and interactions
Side effects & risks
- FDA raises potential immunogenicity, aggregation and peptide-impurity concerns for this fragment.
- The likelihood of uncommon harms and effects of repeated human exposure are unknown.
This is a summary of the cited evidence, not a complete product label. A lack of human safety data does not establish safety.
Clinical research
Mostly animal or lab researchThe direct fragment sources concern chemical identification and detection in horses. They do not demonstrate human injury treatment.
Studies
Identifies the N-terminal acetylated 17–23 fragment.
Equine analytical study, not a human treatment trial.
Personal experiences
Reports describe what someone noticed. They cannot establish cause, typical results, or how often a side effect happens. Amounts and schedules describe the individual account, not an effective or safe dose. Product identity and strength may be unverified, and missing details are left explicit.
No attributable personal accounts were found in the sources reviewed.
Approval status
FDA identifies thymosin beta-4 fragment LKKTETQ as TB-500 and reports inadequate human exposure and safety information. No FDA-approved recovery use is established.
Preclinical evidence; no FDA-approved product
Approval covers the labeled product, use and population. A trial phase does not establish success; a stopped program is not ongoing research.
Open questions
- Reliable human tendon-healing outcomes
- Exact identity of products using the TB-500 name
- Repeated-use safety and interactions
Summary
Evidence from full-length thymosin beta-4 cannot be assigned automatically to TB-500.
Sources
Medical evidence and regulatory sources are listed here. Personal reports are linked separately in the experiences section.
- fdaFDA: safety concerns for nominated bulk substances
Ingredient-specific uncertainties; compounding consideration is separate from FDA drug approval.