Peptide Regulation Watch · Substance File
Thymosin alpha-1
Not Listed
STATUS VERIFIED AUGUST 22, 2026 · HAS A SHELF LIFE
A thymic peptide studied for immune modulation — compounded today under enforcement discretion, not approval.
Also encountered as: Thymosin alpha-1 · Ta1 · class: immune
Where it actually stands
Industry summaries routinely place this substance in FDA's interim Category 1. Checked against FDA's own records, it is not in Category 1 — it sits in the withdrawn-nominations table on FDA's safety-risks page. No enforcement-discretion assurance attaches. Anyone quoting Category 1 status for this substance is citing a secondary source; verify against FDA's current list before any formulary decision.
The one-sentence version: not on FDA’s list — the Category 1 status widely attached to this substance does not match the record.
The record
APR 22, 2026
FDA's bulk substances / safety-risk category pages last updated — the placement behind this status.
AUG 9, 2026
Status verified against the category pages for the Q3 2026 brief. Re-verify before acting — interim placements move.
Primary sources
FDA bulk substances / safety-risk pages (updated 4/22/26) · industry compounding summaries, cross-checked for the Q3 2026 brief. Full citation list available on request.