Peptide Research Hub
Educational reference
Educational reference only. Nothing on this site is medical advice. Many compounds described here are not FDA-approved, lack adequate human evidence, and may be illegal in your jurisdiction. Always consult a licensed clinician.

Healing & Tissue Repair

Thymosin Alpha-1

Thymalfasin

Also known as: Tα1 Zadaxin Thymalfasin

Evidence: Strong clinical Disclaimer: Elevated Approved outside the US (Zadaxin)
Elevated-disclaimer compound. Not approved by the FDA. Evidence is limited to animal models or small human studies. Safety in humans has not been established.

Mechanism & research context

Modulates T-cell function and innate immunity. Studied as an adjunct in chronic hepatitis B/C and sepsis.

Origin: Synthetic version of an N-terminal fragment of prothymosin alpha.

FDA-approved indication: Not FDA-approved in the United States. Approved in 30+ countries for hepatitis B and C as Zadaxin.

Safety flags

0 flags

No curator-recorded safety flags for this entry. Absence of recorded flags is not evidence of safety. Many peptides lack adequate human data.

Research papers

17 records

Citation links route to PubMed, Europe PMC, and PMC. Presence of a study is not endorsement. Records are refreshed from PubMed on a regular cadence; rows marked “Live search link” will resolve to a current PubMed search until a full citation has been ingested.

Clinical trials

21 records
  • Live search Live search

    Live ClinicalTrials.gov search: Thymosin Alpha-1

    Condition: See live results

    Open on ClinicalTrials.gov ↗
  • NCT00040027 PHASE3 COMPLETED

    Thymosin Plus PEG-Interferon in Non-Cirrhotic Hepatitis C Patients Who Did Not Respond to Interferon or Interferon Plus Ribavirin

    Condition: Hepatitis C; Hepatitis C, Chronic

    Sponsor: SciClone Pharmaceuticals

    Open on ClinicalTrials.gov ↗
  • NCT00082082 PHASE2 COMPLETED

    A Trial of Thymalfasin With Trans Arterial Chemo-Embolization (TACE) in the Treatment of Adult Patients With Unresectable Hepatocellular Carcinoma: A Phase II Trial

    Condition: Carcinoma, Hepatocellular

    Sponsor: SciClone Pharmaceuticals

    Open on ClinicalTrials.gov ↗
  • NCT00911443 PHASE2 COMPLETED

    A Phase II, Multicentre, Open, Randomised, Dose Ranging Study to Investigate the Efficacy of Combination Therapy Containing Dacarbazine (DTIC) Plus Low Dose Interferon Alpha (aIFN) Plus Thymosin a1 Versus Both DTIC Plus Thymosin a1 and DTIC Plus aIFN in Patients With Advanced -Stage Metastatic Malignant Melanoma

    Condition: Malignant Melanoma

    Sponsor: sigma-tau i.f.r. S.p.A.

    Open on ClinicalTrials.gov ↗
  • NCT01178996 PHASE3 COMPLETED

    A Phase III, Multicentre, Double Blinded Study In Patients With Chronic Hepatitis C Who Are Non-Responders To Prior Peginterferon Alpha + Ribavirin Therapy Comparing Treatment With Thymosin Alpha 1 + Peginterferon Alpha-2a Plus Ribavirin With Peginterferon Alpha-2a + Ribavirin + Placebo

    Condition: Chronic Hepatitis C

    Sponsor: sigma-tau i.f.r. S.p.A.

    Open on ClinicalTrials.gov ↗
  • NCT01943617 PHASE4 COMPLETED

    Optimized Treatment and Regression of HBV-induced Compensated Liver Cirrhosis

    Condition: Liver Cirrhosis

    Sponsor: Beijing Friendship Hospital

    Open on ClinicalTrials.gov ↗
  • NCT02281266 PHASE4 UNKNOWN

    Investigator Initiated Study of Thymosin in HBV-related HCC

    Condition: Curable Hepatitis B Virus-Related Hepatocellular Carcinoma

    Sponsor: Jia Fan

    Open on ClinicalTrials.gov ↗
  • NCT02787447 PHASE2 UNKNOWN

    A Phase II Trial of Hypofractionated Radiotherapy Combined With Thymosin for Metastatic NSCLC Patients Who Showed Stable Disease After First Line TKI Therapy

    Condition: Lung Adenocarcinoma

    Sponsor: First People's Hospital of Hangzhou

    Open on ClinicalTrials.gov ↗
  • NCT02883595 PHASE4 COMPLETED

    Efficacy of Thymosin Alpha 1 on Improving Monocyte Function for Sepsis

    Condition: Sepsis

    Sponsor: Sun Yat-sen University

    Open on ClinicalTrials.gov ↗
  • NCT03082885 NA COMPLETED

    A Randomized Controlled Trial to Evaluate Efficacy and Safety of Thymosin-α1 Administration in Patients With HBV-related Acute-on-chronic Liver Failure

    Condition: Liver Failure

    Sponsor: Sun Yat-sen University

    Open on ClinicalTrials.gov ↗
  • NCT03448744 PHASE4 UNKNOWN

    A Multicenter, Randomized, Open-label Control Study to Evaluate Efficacy and Safety of Combination Therapy of Thymalfasin and Entecavir in HBeAg-positive ETV-experienced Patients

    Condition: Chronic Hepatitis b

    Sponsor: Wen-hong Zhang

    Open on ClinicalTrials.gov ↗
  • NCT04320238 PHASE3 UNKNOWN

    An Clinic Trial of Recombinant Human Interferon Alpha Nasal Drops to Prevent Coronavirus Disease 2019 in Medical Staff in Epidemic Area

    Condition: 2019 Novel Coronavirus Infection

    Sponsor: Shanghai Jiao Tong University School of Medicine

    Open on ClinicalTrials.gov ↗
  • NCT04428008 PHASE2 COMPLETED

    A Pilot Trial of Thymalfasin (Ta1) to Prevent COVID-19 Infection in Renal Dialysis Patients

    Condition: COVID-19

    Sponsor: William B. Ershler, MD

    Open on ClinicalTrials.gov ↗
  • NCT04487444 PHASE2 TERMINATED

    A Pilot Trial of Thymalfasin (Ta1) to Treat COVID-19 Infection in Patients With Lymphocytopenia

    Condition: Covid19

    Sponsor: Rhode Island Hospital

    Open on ClinicalTrials.gov ↗
  • NCT05339529 NA RECRUITING

    Protective Effect of Thymosin Α1 Against Negative Immune Dysregulation and Organ Dysfunction After Acute Aortic Dissection Surgery (PANDA II)

    Condition: Acute Aortic Syndrome; Aortic Dissection Type a

    Sponsor: Nanjing Medical University

    Open on ClinicalTrials.gov ↗
  • NCT05487469 NA UNKNOWN

    Thymosin α1 Use in Rheumatic Heart Disease Patients Undergoing Cardiac Surgery on Cardiopulmonary Bypass

    Condition: Rheumatic Heart Disease; Cardiopulmonary Bypass; Immunotherapy

    Sponsor: Nanjing Medical University

    Open on ClinicalTrials.gov ↗
  • NCT05790447 PHASE2 UNKNOWN

    Treatment of Advanced Refractory Solid Tumors Based on Precise Thymalfasin-regulated PRaG Mode: an Open-label, Prospective, Multicenter Study (PRaG 5.0 Study)

    Condition: Advanced Solid Tumor; Refractory Tumor

    Sponsor: Second Affiliated Hospital of Soochow University

    Open on ClinicalTrials.gov ↗
  • NCT06139419 PHASE2 ACTIVE_NOT_RECRUITING

    A Prospective Phase II Controlled Study to Evaluate the Impact of Thymosin Alpha 1 on the Completion Rate of Consolidation Immunotherapy After Radical Radiochemotherapy for Locally Advanced Non-Small Cell Lung Cancer

    Condition: Non-small Cell Lung Cancer

    Sponsor: Sun Yat-sen University

    Open on ClinicalTrials.gov ↗
  • NCT06573398 PHASE2 NOT_YET_RECRUITING

    Efficacy and Safety of Radiotherapy With Sequential Chemotherapy Combined With PD-1 Inhibitor and Thymalfasin for Borderline Resectable Pancreatic Cancer

    Condition: Carcinoma, Pancreatic Ductal

    Sponsor: Ruijin Hospital

    Open on ClinicalTrials.gov ↗
  • NCT06598839 NA RECRUITING

    Assessment of the Efficacy of Immunomodulatory Therapy With Thymosin Alpha 1 (Tα1) Following Surgical Resection in Patients With Stage I Non-Small Cell Lung Cancer

    Condition: Non Small Cell Lung Cancer

    Sponsor: Yousheng Mao

    Open on ClinicalTrials.gov ↗
  • NCT07103408 PHASE2 NOT_YET_RECRUITING

    A Phase II Study Evaluating Concurrent Chemoradiotherapy Combined With Dual Immune Checkpoint Blockade (PD-1/CTLA-4) for Limited-stage Small Cell Lung Cancer

    Condition: Small-Cell Lung Cancer (SCLC)

    Sponsor: Sun Yat-sen University

    Open on ClinicalTrials.gov ↗

Doses reported in studies

0 records
This is not a dosing guide. Entries below are historical metadata transcribed verbatim from a cited clinical-trial protocol, published study, or FDA-approved label. They describe what was administered in a specific study population under medical supervision — they are not recommendations, not common-use guidance, and may not be safe or appropriate outside the cited context. Doses widely discussed in community/anecdotal sources are not shown here; see the safety policy for why.

No study-protocol dose records have been curated for Thymosin Alpha-1 yet. Absence of records is not evidence of safety — many peptides lack adequate human-trial data in the first place.

Records here are populated from public sources only (ClinicalTrials.gov protocol summaries and FDA-approved labels) and must cite a verifiable source URL. They are not added from forum posts, vendor pages, anecdotal write-ups, or social media.

These entries describe what was studied. They do not tell you what to take, how to reconstitute anything, how to fill a capsule, how often to administer, or where to obtain a compound. If you are considering use of Thymosin Alpha-1, those decisions belong with a licensed clinician working from the full label or trial record — not from this summary.

Why this page does not list a dose for self-use

The "Doses reported in studies" section above (when populated) describes what was administered in a cited study or label, under medical supervision, in a specific population. It is not a dosing guide for self-use. Separately, we do not publish anecdotal or community-reported dose ranges, administration methods, vial concentrations, or capsule masses for Thymosin Alpha-1. Anecdotal figures for unapproved compounds are not harm-reduction data: they lack denominators for adverse events, cannot account for individual physiology or compound purity, and normalise unsupervised use. See the safety policy for the full reasoning.

If this compound has an FDA-approved label

If a label exists, the regulator-reviewed dosing and administration information is there — read it in the context of a prescriber's evaluation.

Questions worth bringing to a clinician

  • What is the evidence for this compound in someone with my history?
  • What are the realistic, regulator-reviewed alternatives?
  • What would you monitor, and what would make you stop?

If you have already taken a peptide and feel unwell: contact emergency services. In the United States, Poison Control is reachable 24/7 at 1-800-222-1222. Do not wait for a community thread.

Research peptides are not substitutes for medical care. If you are considering any peptide for health purposes, speak with a board-certified physician or endocrinologist first.