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TB-500: Evidence, Legal Status, and Safety

TB-500 is sold as a synthetic fragment related to thymosin beta-4, pitched for the same injury-recovery use case as BPC-157 and often stacked with it. The honesty-critical distinction: the full-length parent molecule has some human safety and wound-healing data, but the synthetic fragment sold as “TB-500” has essentially no dedicated human trial data of its own. It is not FDA-approved for any human use.

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What the evidence says
What it is

Understand what's actually being sold

A synthetic peptide fragment modeled on thymosin beta-4, a naturally occurring protein involved in cell migration and wound healing, promoted for the same injury-recovery use case as BPC-157 and often stacked with it.

The name refers to a fragment of the parent protein, not the full molecule that has been studied in humans.

2026 scoping review of thymosin beta-4 / TB-500 literature
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Evidence tier: C

See what belongs to TB-500 versus its parent molecule

The parent molecule (full-length thymosin beta-4) has some human data: a completed Phase 1 safety study and Phase 2 wound-closure data. The synthetic fragment sold as TB-500 has essentially no dedicated human trial data of its own; a 2026 scoping review found direct TB-500 evidence limited to a single included study.

This is the single most important honesty point on this page: the human data belongs to the parent molecule, not the product being sold.

2026 scoping review, mdpi.com/2076-3417/16/12/6202
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Legal status

Know where it stands

Not FDA-approved for any human use; sold as an unregulated research chemical, the same category as BPC-157. The thymosin beta-4 fragment is among bulk substances the FDA has flagged for limited human-safety data.

There is no regulatory pathway making TB-500 a legal medical product in its current form.

FDA compounding-risk reporting
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Safety

Know the real risk

Same unregulated-manufacturing risk as BPC-157: no purity or sterility guarantee, and no completed human safety trial specific to the synthetic fragment as sold. It is frequently stacked with BPC-157; taking two unapproved, unregulated peptides together compounds unknown risk rather than averaging it out.

Stacking is a popular marketing pattern, not a safety strategy.

Huberman Lab peptide-therapeutics episode
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What it is

TB-500 is a synthetic peptide fragment modeled on thymosin beta-4, a naturally occurring protein involved in cell migration and wound healing. This page reports the honest evidence tier, legal status, and safety picture; it does not describe how to use it.

Why it works▼
Thymosin beta-4, the naturally occurring protein TB-500 is modeled on, has some real human data: a completed Phase 1 safety study in healthy volunteers found intravenous recombinant thymosin beta-4 well-tolerated with no dose-limiting toxicity, and Phase 2 trials showed accelerated wound closure in some skin-wound settings. A 2026 scoping review of the broader literature found human evidence concentrated in eye or cornea and skin or wound settings, with direct TB-500 evidence limited to a single included study. Attributing the parent molecule's human data to “TB-500” itself would be evidence-laundering, so this page keeps that distinction explicit: the fragment sold online has essentially no dedicated human trial data of its own. It carries the same unregulated-manufacturing risk profile as BPC-157, and it is frequently stacked with BPC-157; stacking two unapproved, unregulated peptides compounds unknown risk rather than averaging it out. Andrew Huberman's Huberman Lab episode on peptide therapeutics describes TB-500/thymosin beta-4 as having wound-healing and stem-cell claims backed only by animal evidence, with no human trials of the fragment itself.
The evidence
Sources 2
Primary sources behind this page, cited straight to the source: peer-reviewed papers and reporting. Select any to view it here.
1
2026 scoping review of thymosin beta-4 / TB-500 human evidence
Paper · MDPI, Applied Sciences
2
Huberman Lab: Benefits & Risks of Peptide Therapeutics for Physical & Mental Health (TB-500/thymosin beta-4 segment)
Article · hubermanlab.com
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Is this for you?
Good fit if
  • Anyone considering TB-500 who wants the honest evidence before discussing it with a clinician
  • Anyone who has seen BPC-157 and TB-500 marketed together as a “stack”
  • Readers who want to know what evidence actually belongs to TB-500 versus its parent molecule
  • Readers comparing research chemicals to FDA-approved peptides
Cautions
  • Not FDA-approved for any human use; sold as an unregulated research chemical with no purity or sterility guarantee.
  • The human data most often cited for “TB-500” actually belongs to the full-length parent molecule, thymosin beta-4, not the fragment sold online.
  • Frequently stacked with BPC-157; combining two unapproved, unregulated peptides compounds unknown risk.
  • Educational only, not medical advice.
Common questions
Is TB-500 the same as thymosin beta-4?▾
Not exactly. TB-500 is sold as a synthetic fragment related to thymosin beta-4, the naturally occurring parent protein. Most of the human safety and wound-healing data that exists belongs to the full-length parent molecule, not the fragment sold as TB-500.
Has TB-500 itself been tested in humans?▾
A 2026 scoping review found direct human evidence for the TB-500 fragment limited to a single included study. The stronger human data (Phase 1 safety, Phase 2 wound-closure results) belongs to the parent molecule, thymosin beta-4.
Is it safe to stack BPC-157 and TB-500?▾
There is no completed human safety data for that combination. Stacking two unapproved, unregulated research chemicals compounds unknown risk rather than averaging it out.
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Not medical advice. This page is for education only and is not a substitute for professional medical care. Consult a qualified clinician before changing your health routine.
Editorial disclosure. This protocol is written and fact-checked by the YourProtocol editorial team directly from the primary sources cited below; it is not written or reviewed by any outside expert.

TB-500: Evidence, Legal Status, and Safety
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