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No. 008peptide

TB-500

TB-500 is a peptide that is research only, not approved for human use in the US.

Also known as Thymosin beta-4 fragment, Tβ4 fragment, Ac-LKKTETQ

TB-500 is a short synthetic peptide modeled on part of thymosin beta-4, a natural protein involved in cell movement and tissue repair. It is marketed for muscle and tendon recovery and is often mentioned alongside BPC-157.

In 1 example journal

Empty glass test tubes with white caps neatly arranged in a rack, pale and clinical in tone.
Research only · Not for human use
Not approved for human useNot approved for human use in the US. We list it so you can learn what it is, but we do not link to anyone selling it. If you are considering it, a clinician can talk through approved alternatives.
Lawful options in fitness & strength

Is TB-500 legal in the US?

Not approved for human use in the US. We list it so you can learn what it is, but we do not link to anyone selling it. FDA removed it from the Category 2 "significant safety risk" compounding list on April 15, 2026, and FDA's advisory committee narrowly recommended adding it to the 503A bulks list in July 2026. It is not on that list yet: FDA still has to finish rulemaking, so there is no settled lawful compounding route today. The July 2026 vote was 8-6.

As of September 23, 2026.

Key takeaways

  • TB-500 is a short synthetic fragment of thymosin beta-4, a natural repair protein. It is not approved for human use.
  • FDA found no reports of TB-500 being given to patients for any disease, and no toxicity studies.
  • An FDA advisory committee voted 8 to 6 in July 2026 to recommend a compounding route, against FDA staff advice. Nothing is final.
  • Thymosin beta-4 and its derivatives, including TB-500, are banned in sport.

How does TB-500 work?

Proposed from lab and animal studies

Preclinical only: the parent protein, thymosin beta-4, helps cells move and supports new blood vessel growth in animal wound models. TB-500 copies a small part of it.

It is not clear the fragment does what the parent protein does. FDA's review cites a lab study in which TB-500 itself did not speed wound closure.

Bright blue liquid pours from a glass flask into a row of clear laboratory test tubes under clean lab light.
Macro close-up of empty glass sample vial openings arranged in a bright blue laboratory tray.

What does the evidence say about TB-500?

Animal & lab studies only

Evidence for the fragment sold as TB-500 comes from lab and animal studies; FDA noted essentially no human exposure data.

Why are clinicians and regulators cautious about TB-500?

Regulators and sports medicine reviewers describe TB-500 as essentially untested in people.

Summaries of published guidelines, drug labels, regulators and reviews, each attributed to its source. DiscoverMedica does not employ clinicians.

Who should avoid TB-500?

Especially important to avoid if

  • Anyone considering buying it online: it is not made to drug standards
  • People with a current or past cancer, since the parent protein supports cell migration and blood vessel growth
  • Pregnancy or breastfeeding: there are no data
  • Competitive athletes in tested sport

What are the risks and side effects of TB-500?

  • Not approved for human use. Products sold online as "research chemicals" are not made to drug standards, so identity, purity, sterility and dose are unverified.
  • FDA flagged a potential for aggregation and immune reactions, and the lack of human safety data.
  • Thymosin beta-4 supports blood vessel growth and cell migration, raising a theoretical concern for people with cancer.
  • Prohibited in sport by the World Anti-Doping Agency.

What should you ask a clinician about TB-500?

  • What proven options do I have for this injury?
  • Would any peptide therapy be safe given my medical history?

These save with the compound when you add it to My Journal, so they’re on the printout for your visit.

Where can I get TB-500?

TB-500 is not approved for human use, so DiscoverMedica links to no seller.

We don’t link to sellers of research-only compounds. Products sold “for research use only” are not made for people and are not held to pharmaceutical quality standards.

Compare and learn

TB-500: questions, answered

Is TB-500 the same as thymosin beta-4?

No. It is a short fragment of it. Research on the full protein does not automatically apply to the fragment.

Is there human evidence?

FDA found no published human treatment data for TB-500.

Can I get it from a telehealth provider?

Not lawfully today. TB-500 is not FDA-approved, and it is not yet on the list of ingredients pharmacies may compound from, so a licensed telehealth provider has no approved or compounded product to prescribe. An FDA advisory committee voted in July 2026 to recommend adding it, but FDA still has to decide and complete rulemaking. We will update this page if that changes. DiscoverMedica does not link to anyone selling it.

What does "research use only" mean?

It means the product is not made or tested for people. FDA has sent warning letters to sellers who use that label while making health claims, and says it judges a product by how it is marketed, not by the disclaimer.

Important safety information

TB-500 is not approved for human use in the US. Not approved for human use in the US. We list it so you can learn what it is, but we do not link to anyone selling it.

Key risks

  • Not approved for human use. Products sold online as "research chemicals" are not made to drug standards, so identity, purity, sterility and dose are unverified.
  • FDA flagged a potential for aggregation and immune reactions, and the lack of human safety data.
  • Thymosin beta-4 supports blood vessel growth and cell migration, raising a theoretical concern for people with cancer.
  • Prohibited in sport by the World Anti-Doping Agency.

Avoid it especially if

  • Anyone considering buying it online: it is not made to drug standards
  • People with a current or past cancer, since the parent protein supports cell migration and blood vessel growth
  • Pregnancy or breastfeeding: there are no data
  • Competitive athletes in tested sport

This is not a complete list of risks. Talk to a licensed clinician or pharmacist about your own situation. If you have a severe reaction, call 911. You can report side effects to the FDA through MedWatch at 1-800-FDA-1088.

Sources

Also checked for this guide

Guide reviewed September 23, 2026.

Educational information only, not medical advice. It does not replace a conversation with a licensed clinician.

Example journals

Journals with TB-500.

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