Favorable PCAC vote

TB-500

Also known as Thymosin beta-4 fragment, LKKTETQ, TB-500 acetate

LAST VERIFIEDAug 12, 2026Against linked primary sources
PL
WHAT THIS MEANS NOWNo final legal change
FDA REVIEW STATUSCommittee favored
HUMAN STUDIESNone identified by FDA
WHAT COMES NEXTFDA action
FDA scientific review
Meeting announced
03Committee vote
04Final FDA decision
FDA approved?No
FDA-approved indicationNone
Compounding-list statusNot on the final 503A Bulks List; FDA action pending
Advisory-committee statusFavorable advisory recommendation — July 2026
Final FDA decisionNo final FDA action identified
WHY IT GETS ATTENTION

TB-500 is discussed as a recovery and tissue-repair compound, especially in athletic and post-injury communities.

Reality check

The nominated fragment is not the same thing as proving a clinical effect, and FDA reported no identified human exposure data for the reviewed drug products.

AT A GLANCE

What a visitor should know.

PUBLIC INTERESTHighHow much attention this peptide is receiving
HUMAN STUDIESNo identified human exposureAnimal and laboratory results are kept separate
EVIDENCE GAPVery wideHow far public interest has moved beyond human evidence
NEW EVIDENCEQuietNo post-briefing change in human-evidence classification has been verified in Peplyst's monitored source set.
Technical details: aliases, tracked claims, and data record
MOST RECENT FDA UPDATE

PCAC gave a favorable advisory recommendation

The committee recommended TB-500-related bulk drug substances for possible inclusion on the 503A Bulks List.

What this tells us

FDA received advice from its expert compounding committee.

What it does not tell us

The compound was not FDA-approved, and the vote alone did not add it to the final 503A Bulks List.

WHAT COMES NEXTFDA action

FDA must decide whether and how to act on the committee recommendation.

Read the FDA source
REGULATORY HISTORY

How the FDA record developed.

This timeline separates early nominations and scientific reviews from committee votes and final FDA decisions.

July 23, 2026
PCAC vote

PCAC gave a favorable advisory recommendation

The committee recommended TB-500-related bulk drug substances for possible inclusion on the 503A Bulks List.

Read the source ↗
May 2026
FDA review

FDA published its scientific briefing

FDA released its evaluation of TB-500-related bulk drug substances for the committee meeting.

Read the source ↗
2015
Compounding nomination

TB-500 entered FDA's 503A nomination record

The TB-500 fragment was nominated for wound healing. The nomination was later withdrawn, and FDA continued the evaluation on its own initiative.

Read the source ↗
STUDIES AND EVIDENCE

What has actually been studied?

Human studies appear on the left. Animal, cell, and laboratory studies appear on the right because they cannot establish that a treatment works in people.

H
Human evidenceStudies or observations involving people
FDA evidence review

FDA reported no identified human exposure data for drug products containing the nominated TB-500 fragment.

Read the FDA review
P
Preclinical evidenceAnimal, cell, or laboratory research
Laboratory and animal literature

Preclinical findings were reviewed separately and do not establish clinical benefit in people.

Read the FDA review
Laboratory and rat metabolism study (2024)

Researchers measured TB-500 and its metabolites in laboratory systems and rats; only one metabolite showed significant wound-healing activity in vitro. This is not a human treatment study.

Read the study on PubMed
SAFETY & UNCERTAINTY

Important unknowns.

  • FDA reported no identified human exposure data for the drug products it reviewed.
  • FDA identified uncertainty around active-ingredient characterization, peptide-related impurities, or aggregation.
  • Limited evidence of harm should not be interpreted as evidence of safety.

These are evidence and regulatory uncertainties, not an individualized assessment of whether a treatment is appropriate.

SOURCE DOCUMENTS

Read the original sources.