Skip to content

Reference information only. Therapept does not sell peptides and does not provide medical advice.Research-use notice

Therapept

Synthetic 28-residue N-acetylated peptide corresponding to the N-terminal fragment of prothymosin alpha

Thymosin alpha-1

A synthetic 28-residue peptide with no approved drug product in the United States, though it is marketed in some other jurisdictions.

Also listed as: Thymalfasin, Tα1, Zadaxin

Chemical identity

Compound class
Synthetic 28-residue N-acetylated peptide corresponding to the N-terminal fragment of prothymosin alpha
Sequence
Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN
Molecular formula
C129H215N33O55
Molecular weight
3108.3 g/mol
CAS number
62304-98-7
PubChem CID
16130571
Research categories
Immunomodulatory peptides

United States regulatory status

No FDA-approved product

  • No record found in Drugs@FDA under thymalfasin. Not approved in the United States.
  • Listed on FDA's table of bulk substances nominated for compounding and withdrawn by the nominator.
  • FDA's published concerns state that compounded thymosin alpha-1 may pose significant risk for immunogenicity, and that available safety information is inadequate for the agency to understand the extent of any safety issues.
  • Not named on the WADA 2026 Prohibited List.

Regulatory status describes how a substance is classified. It is not a safety assessment, and it says nothing about the quality of any particular material.

Sources

  1. PubChem CID 16130571
  2. Drugs@FDA — approved drug products
  3. FDA — Certain bulk drug substances for use in compounding may present significant safety risks

Last reviewed 3 September 2026 · Compiled by Therapept Editorial · How these records are built