TB-500
Thymosin beta-4 fragment · LKKTETQ
Synthetic thymosin-beta-4-related fragment researched for wound and tissue-repair biology, with no established human clinical evidence for the fragment itself.
Reference dose
1–2.5 mg
Source-specific educational reference, not an individualized recommendation.
Reference schedule
2–3× weekly · 4–6 weeks
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This page gets detailed quickly.
Profiles include evidence, formats, units, source-specific reference amounts and, where relevant, device details. If any of those terms are unfamiliar, do not guess your way through them. Start with a Personalised Guide and we will put the foundations in the right order for you.
At a glance
What it is
Tβ4 fragment LKKTETQ
FDA uses this identity for TB-500.
Direct human evidence
Not established
FDA reports no identified human exposure data for drug products containing the fragment.
Common evidence error
TB-500 ≠ full Tβ4
Full-length thymosin beta-4 trials are indirect context, not direct TB-500 evidence.
Regulatory status
Not FDA approved
Reviewed in the 2026 503A compounding process.
What it is
TB-500 is commonly sold as a synthetic fragment related to thymosin beta-4. FDA identifies it as the LKKTETQ fragment.
It is often marketed for recovery and tissue repair, but the strongest human thymosin-beta-4 research generally involves the full-length molecule rather than the TB-500 fragment.
Research focus
How it works
TB-500 is described by FDA as the thymosin beta-4 fragment LKKTETQ. Interest in it comes partly from thymosin-beta-4 biology involving actin, cell migration and tissue repair, but evidence for full-length thymosin beta-4 should not automatically be assigned to the shorter TB-500 fragment.
Important context
TB-500 and full-length thymosin beta-4 are routinely blurred together online. FDA specifically identifies TB-500 as the LKKTETQ fragment and states that it has not identified human exposure data for drug products containing that fragment.
What it is studied for
Repair research focuses on cell migration, actin dynamics, angiogenic signalling and wound-related pathways associated with thymosin beta-4 biology.
Sports and recovery communities extrapolate that biology toward muscle, tendon and connective-tissue recovery.
A major evidence question is whether the short TB-500 fragment reproduces clinically meaningful effects attributed to full-length thymosin beta-4.
More contextWhy the thymosin beta-4 distinction mattersSee the deeper context, evidence details and practical distinctions behind this profile.
Full-length thymosin beta-4 has its own preclinical literature and has been studied in humans, including topical wound-healing research.
TB-500 is a shorter fragment. Similarity to part of thymosin beta-4 creates a mechanistic research rationale, but it does not make full-length human trial results direct evidence for injected TB-500.
- FDA lists thymosin beta-4 fragment (LKKTETQ), also known as TB-500, among compounded bulk substances it says may present significant safety risks.
- FDA states that it has not identified human exposure data for drug products containing the TB-500 fragment.
- In July 2026 FDA reviewed TB-500 free base and acetate for possible inclusion on the 503A Bulks List, with wound healing as the evaluated use.
- Human studies of full-length thymosin beta-4 can inform biological context but should be clearly labelled as indirect evidence for TB-500.
Why people are interested
What makes TB-500 worth researching.
Mechanistic / preclinical
Wound-repair rationale
Interest in TB-500 is tied to thymosin-beta-4 biology around cell migration, actin dynamics and tissue-repair pathways.
Indirect human context
Full-length Tβ4 research
Full-length thymosin beta-4 has been investigated in animal models and human topical wound studies, but those data cannot simply be relabelled as TB-500 evidence.
No established human exposure data
Direct evidence gap
FDA states that it has not identified human exposure data for drug products containing the TB-500 LKKTETQ fragment.
Regulatory safety review
Compounding concerns
FDA highlights potential immunogenicity, aggregation and peptide-impurity concerns for compounded TB-500-related products.
Evidence
Where the evidence is strongest, and what kind of evidence it is.
Direct human evidence · absent/very limited
TB-500 fragment
FDA's 2026 safety-risk information states that it has not identified human exposure data for drug products containing thymosin beta-4 fragment LKKTETQ.
Human studies · indirect
Full-length thymosin beta-4
Full-length Tβ4 has human wound-study literature, including topical venous-ulcer research. Molecular and formulation differences mean these data are not direct validation of TB-500 injections.
Preclinical
Preclinical repair biology
Thymosin-beta-4-related research supports interest in actin regulation, cell migration, angiogenesis and repair, but fragment-specific translation remains uncertain.
Regulatory evaluation
FDA compounding review
TB-500 free base and acetate were reviewed by FDA's Pharmacy Compounding Advisory Committee process in July 2026 for wound-healing use.
Human research
FDA states that it has not identified human exposure data for drug products containing thymosin beta-4 fragment LKKTETQ, also known as TB-500.
Full-length thymosin beta-4 has been studied in humans, including topical venous-ulcer research. Those studies are useful biological context but are not direct evidence for TB-500 fragment injections.
Preclinical research
Thymosin-beta-4-related animal and laboratory studies have explored wound healing, cell migration, angiogenesis and tissue remodelling.
Fragment-specific efficacy and pharmacokinetic evidence is much less mature than the broad full-length thymosin-beta-4 literature often cited around TB-500.
Reference dosing
Reference amount, schedule and conversion.
A reference amount is only useful when you know the formulation, concentration and delivery device it belongs to. Do not transfer a vial amount into a pen, a pen click count into another pen, or a syringe-unit number into a different concentration.
01
Identify the format
Vial, reusable cartridge pen, prefilled multi-dose pen or single-dose autoinjector.
02
Confirm concentration
Know the total peptide amount and liquid volume or the manufacturer/vendor concentration.
03
Understand the units
Keep mg/mcg, mL and syringe units or device clicks separate.
04
Then use the reference
Only convert a known reference amount with the calculator that matches the actual device.
Source-specific reference
1–2.5 mg
2–3× weekly · 4–6 weeks
The 1–2.5 mg range is a Pep Report research reference carried through from the original dosing library. It should be read alongside the limited direct human evidence for the TB-500 fragment.
Calculator connection
Choose the calculator that matches the actual formulation. The calculator converts numbers you already know; it does not choose the target amount.
A vial calculator can convert a known concentration, but it cannot establish identity, purity, a clinically supported dose or equivalence to full-length thymosin beta-4 research.
Storage
Start with the format. Then verify the exact product.
Rule of thumb, not a product instruction
Storage belongs to the exact formulation. Generic advice can orient you, but the label, pharmacy directions or formulation-specific stability data should determine the final temperature and usable-life limits.
Pens
Treat a pen as a finished drug-device product: protect it from unnecessary heat and light, do not freeze unless the exact label explicitly permits it, and use that device's own unopened and in-use storage window.
Vials
Treat dry and reconstituted vials as different stability states. Refrigeration after mixing is common for some formulations but is not a universal peptide rule.
Product-specific notes
Storage depends on the exact product and formulation; there is no FDA-approved TB-500 label providing standardized consumer storage instructions.
Practical reference
Formats
Vial / injectable research formats
Reconstitution & units
Reconstitution changes concentration, not total peptide amount.
A calculation cannot confirm that a vial actually contains the labelled TB-500 fragment at the stated purity.
mg or mcg describe amount; mL and U-100 units describe liquid volume.
Use the vial calculator only as arithmetic for known inputs, not as a source of a recommended TB-500 dose.
Safety, status & open questionsOpen the practical cautionsTB-500 is not an FDA-approved drug. The direct human evidence for the LKKTETQ fragment is substantially weaker than online discussions often imply.
Open questions
The extent to which the LKKTETQ fragment reproduces full-length thymosin-beta-4 effects in humans is not established.
There is no approved human TB-500 dose, route or treatment schedule.
Online products may vary in identity, purity, concentration and formulation.
Regulatory notes
TB-500 is not an FDA-approved drug.
FDA identifies thymosin beta-4 fragment LKKTETQ, also known as TB-500, among bulk substances with potential significant safety concerns in compounding.
In July 2026 FDA reviewed TB-500 free base and acetate through the 503A Bulks List advisory process for wound-healing use.
Practical notes
Direct human safety data for the TB-500 fragment are insufficient to define a reliable adverse-effect profile.
FDA cites potential immunogenicity, aggregation and peptide-impurity concerns for compounded TB-500-related products.
Injectable research products add sterility and concentration risks independent of the underlying peptide biology.
Common mistakes
Citing a full-length thymosin beta-4 human trial as if it directly studied TB-500.
Assuming that a short peptide fragment must reproduce the activity and pharmacokinetics of the full-length parent molecule.
Treating popular recovery cycles as clinically validated human dosing.
Using calculator precision as a substitute for evidence about product identity or appropriate dosing.
Common questions
Is TB-500 the same as thymosin beta-4?
Not exactly. FDA identifies TB-500 as the thymosin beta-4 fragment LKKTETQ. Full-length thymosin beta-4 contains substantially more sequence and has a separate research history.
Does TB-500 have human trials?
FDA states that it has not identified human exposure data for drug products containing the TB-500 fragment. Human trials of full-length thymosin beta-4 are indirect context, not direct TB-500 trials.
Why is TB-500 discussed for recovery?
The rationale comes mainly from thymosin-beta-4-related repair biology involving actin, cell migration and wound processes, plus preclinical research.
Is there an approved TB-500 dose?
No. TB-500 is not FDA approved and there is no validated approved human dosing label.
Related peptides & blends
BPC-157
Synthetic 15-amino-acid peptide with extensive animal research in tissue-repair and gastrointestinal models but very limited human evidence.
Open reference →BPC-157 / TB-500 (Wolverine)
Research blend name for BPC-157 + TB-500; one 2026 rat tendon study tested the combination directly, but no controlled human blend trial has established efficacy or dosing.
Open reference →References