TB-500
Reviewed
Short answer
A seven-amino-acid piece of thymosin beta-4 promoted for repair, without reliable human healing evidence and with major product and anti-doping limits. No FDA-approved TB-500 drug product.
The Peptide Field explains research. Its pages are not independently medically reviewed, and they do not diagnose, prescribe, or recommend treatment.
Read the study findingsAlso known as TB500 · Ac-LKKTETQ · thymosin beta-4 fragment 17-23
Part of Healing and recovery peptides
Compared with BPC-157
Sold in blends Wolverine · GLOW · KLOW
Legal status Is TB-500 legal? See the status table
Study and product details
What it is
TB-500 is reported as a seven-amino-acid piece, or fragment, of thymosin beta-4. It is not full-length thymosin beta-4, and evidence about the full protein cannot automatically be transferred to the fragment.
Type of peptide: Synthetic thymosin beta-4 fragment. This describes what the substance is or how it works. It does not show that it is safe, effective, or approved.
What has been studied?
- Unclear: There is not enough reliable detail about the product or research to judge.
- Limited: Research is too small or incomplete, or does not directly answer this question.
FDA found no adequate human clinical outcome evidence for compounded TB-500 wound-healing use.
Fragment identity and laboratory findings do not establish a clinical benefit in people.
Human exposure and product-specific safety information are inadequate.
Nomenclature, salt form, purity, sterility, and fragment-versus-protein distinctions create major uncertainty.
Products with the same ingredient can differ.
The ingredient name does not tell you everything about a product. Check its other ingredients, its form, how it enters the body, and the use and people covered by the research or approval.
None identified in the United States.
- No FDA-approved indication
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What studies found
FDA has published a detailed 2026 briefing on TB-500's identity, characterization, proposed wound-healing use, and evidence gaps. WADA explicitly names TB-500 on the 2026 Prohibited List.
Reliable controlled studies in people do not establish faster tendon, muscle, or wound healing from TB-500. Safety, purity, sterility, long-term effects, and equivalence of marketed material remain uncertain.
Which products do these findings apply to?
TB-500 is not the same as the full thymosin beta-4 molecule. FDA identifies TB-500 as a seven-amino-acid fragment, not as interchangeable with full-length thymosin beta-4. Internet naming and certificates do not establish product identity or clinical equivalence.
TB-500 side effects and safety: what FDA has said
This page has no trial or drug-label side-effect table for TB-500. FDA keeps a page of bulk substances that may be risky when a pharmacy mixes (compounds) them. Here is what that page says about TB-500, in plain words.
FDA's page does not name specific side effects for TB-500.
- FDA found no data on people who received TB-500 products.
- FDA says it lacks important safety information, including whether it would harm people.
- The body's immune system may react against it. FDA says this risk depends on how it is given.
- The peptide may clump together, which adds to that risk.
- Making it may leave unwanted peptide by-products in the product.
These points come from FDA's review of compounded drugs. They are not a full list of side effects. Having no reports does not mean a product is safe.
Read FDA's exact words
Thymosin beta-4, fragment (LKKTETQ), also known as TB-500: “Compounded drugs containing thymosin Beta-4, Fragment (LKKTETQ) may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation as well as peptide-related impurities. FDA has not identified any human exposure data drug products containing Thymosin Beta-4, Fragment. FDA lacks important information regarding any safety issues raised by this drug, including whether it would cause harm if administered to humans.”
Source: FDA, Certain bulk drug substances for use in compounding that may present significant safety risks , page dated .
Compare side-effect data across peptides
Report a side effect
You can report a suspected side effect to the FDA at 1-800-FDA-1088 or through FDA MedWatch . If a reaction feels serious, get medical care first.
FDA page checked .
Fact checks
3 statements checked. Read what the results mean.
“TB-500 is the same thing as thymosin beta-4.”
FDA describes TB-500 as a seven-amino-acid fragment of the much larger thymosin beta-4 molecule.
- What this answer is based on
- Official record or product label
- Limits of this answer
- Chemical identity, not a claim about all possible biological activity.
Sources for this fact check (1)
“TB-500 accelerates tendon and muscle healing in people.”
The FDA evidence review did not identify adequate human outcome evidence for wound-healing use.
- What this answer is based on
- No reliable studies showing this health result in people
- Limits of this answer
- Clinical tendon, muscle, and wound-healing outcomes in people.
Sources for this fact check (1)
“TB-500 is allowed in tested sport.”
TB-500 is named on the current WADA Prohibited List.
- What this answer is based on
- Official record or product label
- Limits of this answer
- Sport governed by the World Anti-Doping Code.
Sources for this fact check (1)
Questions people ask about TB-500
FDA's page on risky compounding substances says this about TB-500. It does not name specific side effects for TB-500. FDA found no data on people who received TB-500 products. FDA says it lacks important safety information, including whether it would harm people. The body's immune system may react against it. FDA says this risk depends on how it is given. The peptide may clump together, which adds to that risk. Making it may leave unwanted peptide by-products in the product. These points come from FDA's review of compounded drugs. They are not a full list of side effects.
Risks and safety limits
This is not an invitation to experiment. The guide provides no sourcing, reconstitution, injection, cycle, stack, or injury-treatment instructions.
TB-500 is named as a prohibited thymosin-beta-4 derivative on the 2026 WADA Prohibited List and is prohibited at all times for covered athletes.
Reviewed .Check the rules for athletes ↗Read the official rules ↗Terms used in the studies
- molecule
- one specific chemical substance
- outcome
- what the study measured
- compounded
- made for one patient by a pharmacy, or in batches by a permitted outsourcing facility; a compounded drug is not FDA-approved
- mechanism
- how a substance may cause a body change
- biomarker
- a body or lab measurement, not automatically a health benefit
- amino acid
- a small building block that makes peptides and proteins
- indication
- the approved or studied use and patient group
Read the sources
Show 3 sources
Review history
Revalidated TB-500 against the 2026 WADA Prohibited List, where TB-500 and thymosin-beta-4 are named in the prohibited growth-factor category.
Initial brief uses FDA's July 2026 identity and evidence review before final agency action.
Not independently medically reviewed. This page is not a dosing, sourcing, or treatment guide.
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