TB-500
Other ·Insufficient evidence ·Reviewed May 2026
Synthetic thymosin beta-4 fragment marketed for recovery and soft-tissue claims. FDA states it has not identified human exposure data for drug products containing this fragment.
- Unknown product purity, potency, and sterility risk outside regulated drug supply
- Injection-site reactions or infection risk with injectable products
- Immune reactions are possible with peptide impurities or aggregation
- Pregnancy or nursing
- History of cancer or active malignancy unless specifically cleared by an oncologist
The bottom line
Evidence rating insufficient. Most-documented uses: no approved wellness use, human efficacy evidence is insufficient for consumer guidance, reference-only safety profile. 2 sources indexed (2016–2026), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
Thymosin beta-4 biology is linked to actin binding and tissue-repair pathways, but TB-500 fragment products sold for consumer use are not established as clinically effective or safe.1,2
Dosing & protocol.
Route-specific guidance is intentionally not provided for unapproved research peptides.
Full safety detail.
Side effects
- Unknown product purity, potency, and sterility risk outside regulated drug supply
- Injection-site reactions or infection risk with injectable products
- Immune reactions are possible with peptide impurities or aggregation
Contraindications
- Pregnancy or nursing
- History of cancer or active malignancy unless specifically cleared by an oncologist
- Use by competitive athletes subject to anti-doping rules
- Use without clinician supervision
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Reviews & position papers
1- 1Thymosin beta4 Promotes Dermal HealingSource linkedPMIDKleinman HK, Sosne G · Vitam Horm · 2016
Review of thymosin beta-4 wound-healing biology; it does not establish consumer TB-500 safety or dosing.
Reference material
1- 2Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksSource linkedURLU.S. Food and Drug Administration · FDA · 2026
FDA states it has not identified human exposure data for thymosin beta-4 fragment (LKKTETQ), also known as TB-500, and lacks important safety information.
Deep dives & adjacent profiles.
This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.
Use this with your stack
TB-500 in NutriStack.
Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.