Thymic peptide / immune modulator
Thymosin Alpha-1 (Tα1) is a naturally occurring thymic peptide that modulates immune function by enhancing T-cell maturation, dendritic cell activity, and cytokine production. It is marketed as Zadaxin (SciClone Pharmaceuticals) and is approved in over 30 countries for chronic hepatitis B, hepatitis C, and as an immune adjuvant, but is NOT approved by the FDA in the United States. The compound received FDA Fast Track designation for certain oncology indications and has been studied in over 100 clinical trials. During the COVID-19 pandemic, thymosin alpha-1 was investigated as an immune-modulating therapy for severe COVID-19 in multiple countries. Despite extensive international clinical use, the peptide remains unapproved in the US, and the biohacking community has shown growing interest in it for immune support and recovery.
Track regulatory status and clinical trial evidence. Distinguish international approvals from the absence of FDA approval. Do not publish dosing, sourcing, or treatment instructions. Monitor for new COVID-19 or oncology trial data that may shift the evidence landscape.
Thymosin Alpha-1 is approved in 30+ countries (including China, Italy, and parts of Southeast Asia) for chronic hepatitis B, hepatitis C, and immune adjuvant use, but has never received FDA approval in the United States.
FDA Fast Track designation was granted for certain indications (including malignant melanoma), reflecting regulatory interest, but Phase 3 trials have not resulted in US approval to date.
Over 100 clinical trials have been registered on ClinicalTrials.gov studying thymosin alpha-1 across infectious disease, oncology, and immune support contexts.
During COVID-19, thymosin alpha-1 was studied as an immune modulator in severe cases; retrospective data suggested potential mortality benefit in critically ill patients, but randomized controlled trial evidence remains limited.
King & Tuthill (2016) published a comprehensive review of immune modulation with thymosin alpha-1 in Expert Review of Clinical Immunology, summarizing its mechanism and clinical development history.
Evidence level: Primary regulatory
Sources: ClinicalTrials.gov / U.S. National Library of Medicine, Expert Review of Clinical Immunology (PubMed)
Approval status should be verified against current FDA records and international regulatory databases on each review cycle. The Fast Track designation does not constitute FDA approval.
Evidence level: Peer reviewed
Sources: ClinicalTrials.gov / U.S. National Library of Medicine, Expert Review of Clinical Immunology (PubMed)
COVID-19 studies are largely retrospective or small-scale. Do not imply proven efficacy. Update if larger randomized controlled trial data become available.
Evidence level: Primary regulatory
Sources: ClinicalTrials.gov / U.S. National Library of Medicine
The number of registered trials reflects research interest, not confirmed efficacy. Verify the current count on ClinicalTrials.gov at each review.
Source records are stored in the repo and linked from each claim.
ClinicalTrials.gov registry search showing 100+ interventional studies of thymosin alpha-1 across infectious disease, oncology, and immune support contexts, including COVID-19 trials.
King R, Tuthill C (2016) comprehensive review (PMID 26653168) of thymosin alpha-1's immune-modulating mechanism, clinical development history, and therapeutic applications including hepatitis, oncology, and sepsis.
SciClone Pharmaceuticals product information for Zadaxin (thymosin alpha-1), approved in over 30 countries for chronic hepatitis B, hepatitis C, and immune adjuvant use. Not FDA-approved in the United States.
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