Peptide library / Immune & defense / Thymosin alpha 1
Thymosin alpha 1
A 28 amino acid thymus peptide approved in dozens of countries but not in the United States.
Effects studied or claimed
What it is used or promoted for, and where each effect has actually been seen
- Hepatitis B and C, adjunctLarge trials
- Immune support in sepsisLarge trials
- Vaccine response in older adultsSmall human studies
How it is thought to work
Thymosin alpha 1 activates dendritic cells and T cells through toll-like receptors, boosting the immune response to infection or vaccines.
What the evidence shows
Used for years in China and elsewhere. A large trial in sepsis in China reported lower 28-day mortality, though the result needs confirmation in other settings.
Safety and unknowns
Generally well tolerated in trials, with mild injection site reactions.
Regulatory status
Approved in many countries. Not FDA-approved.
Regulatory status changes quickly. This entry was last reviewed on 27 October 2026. Confirm current status with the FDA before relying on it.
More in Immune & defense
Thymulin
Wellness and performanceA nine amino acid thymus hormone that needs zinc to work.
Vancomycin
FDA-approvedA glycopeptide antibiotic that remains a mainstay for resistant staph infections.
Thymopentin
In clinical trialsA five amino acid fragment of thymopoietin used as an immune modulator in parts of Europe.
General information, not medical advice. Do not buy or inject unregulated peptides.