The short answer: there is no US approval for this treatment as of September 28, 2026. Permission to use it in Italy does not give US approval. A government panel’s advice does not give that approval either.
The direct US answer
The Food and Drug Administration (FDA) oversees US drugs; as of September 28, 2026, it had approved no medicine containing thymosin alpha-1. There is also no FDA-approved prescribing label for it: the full medicine instructions for health professionals, rather than the sticker on a bottle.
What approval abroad tells us
As of September 28, 2026, Italy allows thymalfasin (Zadaxin) to be used by prescription. The FDA and European Medicines Agency describe its use there as an extra treatment given with the flu vaccine to people whose body defences are weak.
As of September 28, 2026, that Italian authorisation does not give a product permission to be sold in the United States.
What making a medicine at a pharmacy means
For one patient, compounding creates or changes medicine instead of using a ready-made medicine. A pharmacist, doctor or registered facility can do this when the rules allow it.
The public record
The panel advised against letting pharmacies use it
At its December 4, 2024 meeting, the FDA’s advisory panel considered two forms of the ingredient: thymosin alpha-1 free base and thymosin alpha-1 acetate. These are different chemical forms of the same peptide. The panel voted against adding either form to the list of ingredients that ordinary compounding pharmacies may use.
For each form, 17 members voted against adding it and 4 voted in favour. The panel gives advice to the FDA; the FDA must go through its process for making a rule to change the list.
As of September 28, 2026, no final FDA rule had added it to the list. It still did not meet the ingredient rules for an ordinary pharmacy to make a medicine from it.
Help to develop a drug is not permission to sell it
As of September 28, 2026, FDA records show that thymalfasin was given orphan-drug status, a form of support for developing drugs for rare conditions. That status did not lead to an approved medicine. It is not permission to sell the treatment.
Ask about the exact medicine
What exact product is being discussed?
Which country and which use does an approval claim refer to?
What record supports that claim?
If a pharmacy will make this medicine, which current rule allows it to use this ingredient?