Peptide library · Skin & longevity
Thymosin Alpha-1
Thymalfasin · Zadaxin
Approved outside US35countries where it's been approved as a medicine (Zadaxin), mainly for hepatitis B and C and as a vaccine booster
What it is
A 28 amino acid peptide first isolated from the thymus, the gland that trains your immune T cells. Its job is immune signaling.
Why researchers are interested
- One of the few research peptides with decades of human use as an approved drug abroad.
- Studied as a vaccine booster in older adults and dialysis patients who respond poorly to vaccines.
- Investigated as an immune support in hepatitis, sepsis and cancer care.
Good to know
- Not FDA approved in the US.
- Immune effects depend heavily on the condition studied, so results don't carry over automatically to healthy people.
Evidence level: 3 of 5
Sources
DrugBank DB04900 (thymalfasin); Goldstein AL et al., thymosin research 1970s to present
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Educational content only. Not medical advice. Last reviewed 2026-10-17.