Thymosin alpha-1 (thymalfasin) is a 28-amino-acid acetylated peptide originally isolated from thymus tissue that acts through Toll-like receptors on dendritic.
Amounts reported for Thymosin Alpha-1 are listed under Reported protocols, each with its source and study kind. No amount ladder is inferred from them. This is educational source context, not a protocol or recommendation.
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Human study rows are described per source under Reported protocols; they belong to their trial populations and are not a general amount.
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What published studies and recent community write-ups report about amounts, timing and course length. 5 clinical and 2 community-reported rows, each linked to its source. These are descriptions of what others report, not instructions, and nothing here is medical advice.
| Context | Dose | Frequency | Route | Course | Source |
|---|---|---|---|---|---|
| Clinical5 rows | |||||
| TESTS: Phase 3 placebo-controlled sepsis trial1,106 adults aged 18-85 with sepsis at 22 Chinese centers, 2016-2020 | 1.6 mg in 1 mL of sterile water | Every 12 hours | Subcutaneous | 7 days, unless discharged from intensive care or withdrawnNot applicable | BMJ (PubMed)2025 |
| 28-day mortality was 23.4% with thymosin alpha-1 and 24.1% with placebo, a null result, and no secondary or safety outcome differed. The authors chose 1.6 mg twice daily because the twice-weekly hepatitis dose seemed too low for sepsis given the drug's half-life of about 1.5 hours; prespecified subgroups hinted at benefit in people aged 60 or over or with diabetes and harm in younger patients, which the authors flag as hypothesis-generating. SciClone, the manufacturer, supported the trial. | |||||
| ETASS: earlier randomized severe-sepsis trial361 ICU patients with severe sepsis at six Chinese teaching hospitals, 2008-2010 | 1.6 mg (Zadaxin, reconstituted to 1.6 mg/mL) | Twice daily for 5 days, then once daily for 2 days | Subcutaneous | 7 daysNot applicable | Critical Care (PubMed)2013 |
| Mortality at 28 days was 26.0% versus 35.0% in controls, which reached significance only on the log-rank test, and monocyte HLA-DR recovered faster in the treated group. This single-blind trial is what motivated the larger TESTS trial, which did not confirm the mortality signal. | |||||
| Randomized trial added to peginterferon in chronic hepatitis B51 HBeAg-positive chronic hepatitis B patients in Korea | 1.6 mg | Twice a week | Subcutaneous, alongside 180 mcg peginterferon alfa-2a weekly | 12 weeks of thymosin alpha-1 within 48 weeks of peginterferonNot applicable | Scandinavian Journal of Gastroenterology (PubMed)2012 |
| Combined response rates (HBeAg seroconversion, viral suppression and normal ALT) were 23.1% with the combination and 20.0% with peginterferon alone at follow-up, so the short course added nothing measurable. The hepatitis indication predates direct-acting antivirals and nucleoside analogs, and reviews now describe it as historical. | |||||
| Randomized pilot trial for COVID-19 prevention in dialysis patients (NCT04428008)189 adults on maintenance hemodialysis in Kansas City, 2021-2023 (91 treated, 98 standard care) | 1.6 mg in 1 mL | Twice weekly, after dialysis | Subcutaneous | 8 weeks, with 6 months of follow-upNot applicable | ClinicalTrials.gov2023 |
| This is the one US trial registration with results posted for the standard twice-weekly dose; it was open-label with no placebo and counted COVID-19 infections, hospitalizations and deaths over 6 months. The registry page lists the design and arms but the outcome tables need to be read on the record itself. | |||||
| Comprehensive review of dosing across indicationsPatients with chronic viral hepatitis, cancers, sepsis and immunodeficiency across the published literature | Single doses of 0.8-6.4 mg; multiple-dose courses of 1.6-16 mg for 5-7 days | Usually twice a week | Subcutaneous | Varies by indication; hepatitis B regimens ran 26-52 weeksNot described | World Journal of Virology (PubMed)2020 |
| The review records a 40.6% complete virological response with 1.6 mg twice weekly in hepatitis B, calls the drug well tolerated across doses, and argues for repurposing it in COVID-19. It is a narrative review from a single hospital system rather than a systematic analysis. | |||||
| Community-reported2 rows | |||||
| Community dosing chart built around the clinical dose | 1.6 mg (about 3.2 mg per week) | Twice weekly, for example Monday and Thursday | Subcutaneous, from a 5 mg vial reconstituted with 2 mL of bacteriostatic water (2.5 mg/mL, so 1.6 mg is 64 units on a U-100 syringe) | 8-26 weeks commonly describedNot specified | Community resource2025 |
| This 2025 chart reproduces the clinical twice-weekly schedule exactly and adds the syringe math and a 7-day limit on a reconstituted vial. It states plainly that the drug is approved in 35 or more countries but not in the United States, where it is investigational, and frames every figure as research reference only. | |||||
| Community guide with course length and weight adjustment | 1.6 mg; 40 mcg/kg for adults under 40 kg | Twice weekly, 3-4 days apart | Subcutaneous in the abdomen, thigh or upper arm; a 10 mg vial in 2 mL gives 5 mg/mL and six doses | 6 months in hepatitis B monotherapy and cancer-adjunct use; up to 12 months in hepatitis C combination useNot specified | Community resource2026 |
| This guide traces almost every published dose back to the one core 1.6 mg twice-weekly protocol and takes the under-40 kg adjustment from the Zadaxin clinical materials. It makes no claim beyond the approved indications and describes the figures as research-context dosing. | |||||
Plus 2 community resources (dosing guides, forum threads and vendor write-ups), reported above but not linked.
Thymosin alpha-1 (thymalfasin) is a 28-amino-acid acetylated peptide originally isolated from thymus tissue that acts through Toll-like receptors on dendritic and other immune cells to promote T-cell maturation and balance cytokine output. Its synthetic form, Zadaxin, is approved in dozens of countries, mainly in Asia, for chronic hepatitis B and as a vaccine or chemotherapy adjunct, and the regimen used in those labels and in most trials is 1.6 mg injected under the skin twice a week; it is not approved in the United States or the European Union. The largest recent trials have been in sepsis, where a 1,106-patient Phase 3 trial published in 2025 found no reduction in 28-day mortality with 1.6 mg every 12 hours for a week.
These themes describe recurring questions in published research. They are not claims of effectiveness or recommendations for use.
Innate defense, inflammatory signaling and barrier models.
28-day mortality was 23.4% with thymosin alpha-1 and 24.1% with placebo, a null result, and no secondary or safety outcome differed. The authors chose 1.6 mg twice daily because the twice-weekly hepatitis dose seemed.
Mortality at 28 days was 26.0% versus 35.0% in controls, which reached significance only on the log-rank test, and monocyte HLA-DR recovered faster in the treated group. This single-blind trial is what motivated the.
Combined response rates (HBeAg seroconversion, viral suppression and normal ALT) were 23.1% with the combination and 20.0% with peginterferon alone at follow-up, so the short course added nothing measurable. The.
This is the one US trial registration with results posted for the standard twice-weekly dose; it was open-label with no placebo and counted COVID-19 infections, hospitalizations and deaths over 6 months. The registry.
The review records a 40.6% complete virological response with 1.6 mg twice weekly in hepatitis B, calls the drug well tolerated across doses, and argues for repurposing it in COVID-19. It is a narrative review from a.
Study models remain visible so laboratory and animal findings are not mistaken for established human outcomes.
5 protocol rows on this page come from human trials, trial registrations, regulator labels or reviews of human data. Approval status and populations are stated per row.
2 rows record what blogs, vendor write-ups or forums describe for Thymosin Alpha-1. None has been verified against primary literature.
Sequence, synonyms and registry identifiers as recorded in PubChem, the National Library of Medicine's open chemistry database. Formula, mass and CAS number are summarized at the top of the page.
Ac-Ser-Asp-Ala-Ala-Val-Asp-Thr-Ser-Ser-Glu-Ile-Thr-Thr-Lys-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn-OH
Thymalfasin, Thymosin alpha 1, Zadaxin, alpha1-Thymosin, Thymalfasin (USAN:INN), UNII W0B22ISQ1C, CCRIS 7707, Thymosin alpha1 (human)
NZVYCXVTEHPMHE-ZSUJOUNUSA-N
(4S)-4-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S,3R)-2-[[(2S,3S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-acetamido-3-hydroxypropanoyl]amino]-3-carboxypropanoyl]amino]propanoyl]amino]propanoyl]amino]-3-methylbutanoyl]amino]-3-carboxypropanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-3-hydroxypropanoyl]amino]-4-carboxybutanoyl]amino]-3-methylpentanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxybutanoyl]amino]-6-aminohexanoyl]amino]-3-carboxypropanoyl]amino]-4-methylpentanoyl]amino]-6-aminohexanoyl]amino]-4-carboxybutanoyl]amino]-6-aminohexanoyl]amino]-6-aminohexanoyl]amino]-4-carboxybutanoyl]amino]-3-methylbutanoyl]amino]-3-methylbutanoyl]amino]-4-carboxybutanoyl]amino]-4-carboxybutanoyl]amino]propanoyl]amino]-5-[[(1S)-3-amino-1-carboxy-3-oxopropyl]amino]-5-oxopentanoic acid
6 curated references, each with its journal, year and study model, plus 2 community resources reported but not linked.