Peptide Knowledge Base · Immune
Thymosin Alpha-1: what it is, what the evidence says, and its real status
Short version
An immune-modulating peptide, studied for immune support.
Education onlyEvidence grade B · Good human evidence
That’s the honest answer. Everything below is the detail.
A genuinely well-studied immune peptide (approved abroad as Zadaxin).
Can you actually get it?
Plain-English verdict: Education only.
Regulatory status: Nomination withdrawn · in no FDA category · FDA advised against 503A listing (Dec 2024 PCAC).
How does Thymosin Alpha-1 work?
A 28-amino-acid peptide that modulates T-cell and innate immune function.
What it does — and what it does not do
What it does: Studied for immune modulation; used clinically abroad as an adjunct in specific conditions.
How honest is the evidence?
Evidence grade B — Good human evidence.
approved abroad; multiple human studies in immune contexts
A grade measures how much human evidence exists, not whether a molecule is good, safe, or worth your interest. Read our grading methodology for what each grade means.
What we still don't know: US regulatory path is unsettled; optimal use outside studied indications is unclear.
WADA status: Not prohibited.
Who should not take it
Discuss immunosuppressive therapy and autoimmune conditions with a clinician.
Sources
Thymosin alpha-1 (Zadaxin) immune-modulation literature
Compounded medications are not FDA-approved. We keep two signals separate and never collapse them: whether you can get something, and what the rule currently says. See the live FDA Peptide Tracker for status.
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Last reviewed · Peptós.LIFE · Not medical advice.
Cite this page
Thymosin Alpha-1. Peptós.LIFE Peptide Knowledge Base. Reviewed Jun 16, 2026. https://peptos.life/peptides/thymosin-alpha-1
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