The first question
What is being offered?
Start with the name of the substance, before the name of a program.
Here, FDA refers to the Food and Drug Administration, the US agency for drugs.
The same building blocks used in proteins form small chains called peptides; thymosin alpha-1 is one of these.
What do the names and proposed effects mean?
This peptide was first discovered in the thymus, a gland inside the chest. This gland helps the immune system, the body’s defences against illness, develop.
Thymalfasin is the name for the man-made form.
Thymosin alpha-1 and TB-500 are different substances; the shared word in their names does not make them the same peptide.
Does “acts on immunity” mean it helps?
Researchers think it can change the activity of cells that help the body fight illness. How it acts in people is still not fully settled.
That idea does not prove that it improves health or treats a disease.
Ask what the offer means by better immunity. Is it promising fewer infections, a test result, or something else? Ask for the study that measured that exact outcome.
Is it an approved medicine here?
There was no US product containing thymosin alpha-1 with FDA approval as of September 28, 2026.
If someone proposes a product, ask for its full name and who made it. Ask which US rule allows this exact product to be supplied. A program name does not answer those questions.