What it is
A synthetic 28-amino-acid peptide identical in sequence to a naturally occurring thymic peptide. Supplied as a lyophilized powder (Zadaxin).
How it works
Modulates T-cell maturation and function and influences innate immune signaling, including Toll-like receptor pathways, in preclinical and clinical studies.
Where it's used
Approved in multiple countries outside the US for chronic hepatitis B and C and as an immune adjuvant. In the US, available only through compounding pharmacies.
Regulatory status
Not FDA-approved; available through compounding pharmacies in the US. Approved in numerous other countries for chronic hepatitis B and C.
Reconstitution
Supplied as a lyophilized powder reconstituted with the supplied or bacteriostatic water prior to subcutaneous injection.
Tracking it
Thymosin Alpha-1 is injectable, so two things matter in a log: when you dosed and where. Rotating sites and writing both down prevents the classic “did I already pin the left side?” problem. with a half-life of about 2 hours, a dose log also lets a tracker model the relative amount still in your system between doses.
Source
Public reference
Last reviewed 2026-06-11