What is Thymosin alpha-1?

The short answer

Thymosin alpha-1 is a lab-made copy of a peptide that the thymus gland makes.

What it is
Thymus peptide studied as an immune modulator.
What people look into
Aging

9 sources
Status as of October 4, 2026
How we source
Ellum doesn't sell peptides.

By Ellum EditorialPublished October 6, 2026Updated October 11, 2026AI use

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What it is

Type: Thymic peptide (28-aa)
Also known as: ta1, thymalfasin, zadaxin
How it works: Thymus peptide studied as an immune modulator.

Regulatory status

Approved outside the US How we label status

As of October 4, 2026, Thymosin alpha-1 is not FDA-approved for any use and is not on FDA's 503A bulks list. It is approved in Italy.

See Thymosin alpha-1 in the Index →

Federal (FDA): Not FDA-approved (openFDA thymalfasin: no records)
503A compounding: No category (nomination withdrawn; removed from Cat 2 2024-09-27); not on 216.23 as of 2026-10-07; not an approved-drug component; 503B Category 3 (as of October 7, 2026)
PCAC history: 2024-12-04: against 4-17-0 (free base and acetate; uses reviewed incl. hepatitis B/C, HIV, cancers); FDA staff: against

Timeline

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Date	What happened	Source
November 10, 2021	FDA warning letter to a compounding pharmacy states that thymosin alpha was not nominated for inclusion on the 503A bulks list.	FDA, event of November 10, 2021, on fda.gov
October 25, 2024	Federal Register notice of an FDA Pharmacy Compounding Advisory Committee meeting lists thymosin alpha-1 among bulk drug substances under consideration for the 503A bulks list.	Federal Register, event of October 25, 2024, on federalregister.gov

References

Sources as of October 4, 2026