U.S. Food and Drug Administration (FDA)
Is TB-500 (thymosin beta-4 fragment) legal in United States?
Not approvedNo FDA approval; FDA lists TB-500 (thymosin beta-4 fragment) as having no identified human exposure data, and a July 2026 advisory vote is non-binding
Not approved as a medicine here.
TB-500, described by FDA as thymosin beta-4 fragment (LKKTETQ), is not approved for any use. FDA's Category 2 page lists it among withdrawn nominations and states FDA found no human exposure data for it. The Pharmacy Compounding Advisory Committee reviewed it for wound healing on 23 July 2026 and, per a law-firm report, voted 8 to 6 with one abstention to recommend it for the 503A bulks list; the vote is advisory and FDA has taken no listing action. Until FDA acts, it is not on the 503A bulks list.
Last verified 2026-09-29 · how we verify
TB-500 (thymosin beta-4 fragment) elsewhere
Sources (4)
- 01Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Category 2 and withdrawn nominations)U.S. Food and Drug Administration · 2026-04-22 · accessed 2026-09-29
- 02July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory CommitteeU.S. Food and Drug Administration · 2026-08-06 · accessed 2026-09-29
- 03Bulk list bound? PCAC backs majority of peptides in two-day public meetingMcDermott Will & Schulte · 2026-07-27 · accessed 2026-09-29
- 04FDA's Advisory Committee Votes on Peptides: What It Does and Does Not MeanMintz · 2026-07-29 · accessed 2026-09-29