What the medicines review found
In 2024, the FDA, the US medicine regulator, assessed research for 12 uses of this peptide.
These included liver infections, cancer and chronic fatigue. The review also asked whether the peptide helps the body's defences build protection after a vaccine.
For every use it assessed, the agency found too little sound evidence to establish that the treatment works.
Uncertainty is a real answer
That finding does not prove the peptide can never help; it means benefit was not established by the evidence reviewed.
As of September 28, 2026, researchers were still testing the lab-made version, thymalfasin, in studies listed in the US government's research database.
A study being listed is not a result, and research status does not mean FDA approval.