The evidence base for thymosin alpha-1 is broader than many Category 2 peptides because Zadaxin and related thymalfasin products have been studied and used abroad. That international record does not create an FDA-approved US product or automatic 503A availability.
Physicians may submit patient-specific prescription requests for thymosin alpha-1 for pharmacy review. Certain preparations may be available now when clinically appropriate, lawfully prescribed, supported by patient-specific documentation, and approved by the dispensing pharmacy. Availability is determined case by case. This is not a consumer access promise; it is a clinical, sourcing, formulation, and regulatory review process. This ingredient is part of an evolving FDA review process for peptide-related bulk substances used in compounding.
The regulated US route is not a wellness-clinic immune peptide protocol. A prescriber may submit a patient-specific request, and RonanRx reviews the clinical rationale, product identity, source documentation, and regulatory posture before any dispensing decision.
In brief
Thymosin Alpha-1 / Thymalin Explained
Thymosin alpha-1 (often called Tα1, or by its generic drug name thymalfasin and brand name Zadaxin) is a small immune-modulating peptide. It was first isolated in the 1970s from bovine thymus glands by Allan Goldstein's lab and is now made by chemical synthesis 1. The thymus is the organ where T-cells mature; Tα1 helps push immature T-cells toward functional maturity and tunes innate-immune signaling.
Outside the United States, Tα1 is sold under the brand name Zadaxin (by SciClone Pharmaceuticals) and is approved in roughly 30 countries, including Italy and China, for chronic hepatitis B, chronic hepatitis C, and as an adjunct to vaccines in patients with weakened immune systems. It has also been studied in severe sepsis and (during 2020) in patients hospitalized with COVID-19 in China 19.
thymosin alpha-1 is not FDA-approved for any US indication. This ingredient is part of an evolving FDA review process. Physicians may submit patient-specific prescription requests for pharmacy review. Availability is determined case by case, and availability may change after FDA review, PCAC discussion, final agency action, or state-board guidance.
Thymosin alpha-1 (thymalfasin), a 28-amino-acid N-acetylated peptide originally isolated from bovine thymus by Goldstein and colleagues in the 1970s and subsequently produced by chemical synthesis
FDA-approval status (US)
Category 2, evolving FDA review process. Valid patient-specific prescription required; supporting clinical rationale may be requested.
International approval
Approved as Zadaxin (thymalfasin) by SciClone Pharmaceuticals in approximately 30 countries (including Italy and China) for chronic hepatitis B, chronic hepatitis C, and as an adjunct to influenza or hepatitis B vaccination in immunocompromised patients. Approval status varies by jurisdiction.
Route
Subcutaneous injection in published clinical trials, typically twice weekly at 1.6 mg per dose
Evidence posture
Multiple randomized controlled trials and meta-analyses in chronic hepatitis B, chronic hepatitis C, and severe sepsis support a well-studied evidence base in the indications where Zadaxin is approved abroad. In the United States the substance has no FDA-approved use and is classified as emerging.
Compounded under
Physicians may submit patient-specific prescription requests for pharmacy review. Availability is determined case by case.
RonanRx position
RonanRx does NOT source, compound, or dispense thymosin alpha-1. This monograph documents the international evidence base and US regulatory status for awareness only. RonanRx will reconsider compounding only if and when FDA reclassifies thymosin alpha-1 to Category 1.
Prescription review
Patient-Specific Prescription Only
Physicians may submit patient-specific prescription requests for Thymosin Alpha-1 / Thymalin for pharmacy review. Certain preparations may be available now when clinically appropriate, lawfully prescribed, and approved by the dispensing pharmacy. Availability is determined case by case.
Made to order, not off a shelf. No batch sits in a warehouse waiting for buyers. Your prescription is what triggers the prep.
Named-patient label. The bottle carries your name. The batch records carry your prescription.
Dose, strength, and route chosen for you. A prescriber who knows your chart decides what gets compounded, not a manufacturer who set the strength for a trial population.
Licensed pharmacist on the hook. A real person, with a license that can be pulled, signs off on every prep. State inspectors check the facility.
Compounded drugs are not FDA-approved. They should not be evaluated using branded-drug trial data. Availability varies by state and prescribed medication.
A research-use-only website ships a vial from a warehouse. There is no prescription, no pharmacist, no facility inspection, and no way to recall the product if something is wrong with it. If the vial is mislabeled, contaminated, or under-potent, there is nobody whose license is at stake.
A 503A compounding pharmacy is the other thing. Your doctor writes the prescription. A licensed pharmacist, whose name is on the label, prepares the medicine in a facility the state inspects. If something goes wrong, there is a person and a license on the hook, and a documented chain of custody on every lot. That accountability is what makes it safe.
What it is
What is Thymosin Alpha-1 / Thymalin?
Thymosin alpha-1 (Tα1) is a 28-amino-acid N-acetylated peptide with the sequence Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN. It is the most-studied member of the thymosin alpha family, a group of immunoregulatory peptides originally isolated by Goldstein and colleagues from bovine thymus extracts in the 1970s 123. The endogenous peptide is cleaved from the precursor prothymosin alpha and is detectable in human thymic epithelial cells and serum.
The synthetic generic name is thymalfasin. The substance is manufactured by solid-phase peptide synthesis and marketed internationally as Zadaxin by SciClone Pharmaceuticals (originally a US biotechnology company; SciClone's US commercial focus is on China and other markets where Zadaxin has regulatory approval). Zadaxin is supplied as a sterile lyophilized powder reconstituted with sterile water for injection prior to subcutaneous administration; the labeled dose in approved territories is 1.6 mg twice weekly 1831.
In the United States, thymosin alpha-1 has no FDA-approved product. The FDA Pharmacy Compounding Advisory Committee reviewed the substance for the 503A bulk-drug-substances list and placed it in Category 2 (insufficient information to evaluate for use in compounding) 3738. RonanRx therefore does not source, compound, or dispense the substance.
How it works
How Thymosin Alpha-1 / Thymalin Works
Class
Thymic peptide (immunomodulatory)
First studied
1970s
Current status
Category 2, evolving FDA review process
Compounding category
Patient-specific 503A on physician request, pending broader FDA review
Thymosin alpha-1 acts as an immunoregulator that modulates both innate and adaptive immunity 33. The dominant mechanistic theme established across two decades of mechanistic work is dendritic-cell activation: Tα1 signals through Toll-like receptors (principally TLR-2 and TLR-9) on plasmacytoid and conventional dendritic cells, triggering MyD88-dependent maturation and a Th1-skewed cytokine response 5. Subsequent work by the Romani group showed that Tα1 also engages indoleamine 2,3-dioxygenase (IDO)-mediated tryptophan catabolism in dendritic cells, producing a tolerogenic regulatory environment that balances inflammation 67.
Downstream effects include enhanced T-cell maturation from CD4−/CD8− thymocyte precursors, augmented natural killer cell cytotoxicity, increased IL-2 receptor expression on T-cells, and partial restoration of suppressed lymphocyte counts and function in immunosuppressed states 33. The 2018 Stincardini review extended the model with a role in cellular proteostasis 8. Net clinical consequences span antiviral effects (chronic hepatitis B and C), restoration of T-cell function in critically ill patients with severe sepsis, and adjunct activity in cancer immunotherapy and vaccine response.
Research history
Thymosin Alpha-1 / Thymalin Research History
The thymic peptide research program that produced thymosin alpha-1 began with Allan Goldstein's group at the Albert Einstein College of Medicine in the late 1960s. The 1972 PNAS paper by Goldstein, Guha, Zatz, and Hardy 1 reported purification and biological activity of 'thymosin', a partially purified bovine thymus extract that restored T-cell function in neonatally thymectomized mice. Subsequent fractionation work by Low, Thurman, and colleagues at George Washington University 2 resolved the partially purified extract into Fractions 5 and 5a containing multiple peptides, of which thymosin alpha-1 was the most active in T-cell maturation assays. The amino-acid sequence was determined in 1977 and chemical synthesis followed shortly thereafter, enabling the transition from bovine-derived to synthetic material 3.
Clinical development through the 1980s and 1990s focused on chronic hepatitis B. The Andreone et al. 1996 Hepatology trial 9 randomized HBeAg-positive chronic hepatitis B patients to thymosin alpha-1 versus interferon alfa and reported comparable rates of HBV DNA clearance with substantially better tolerability for Tα1. The Mutchnick et al. 1999 multicenter phase III placebo-controlled trial 10 reported a sustained virologic response advantage. Subsequent combination regimens with lamivudine 12 and meta-analytic synthesis 11 consolidated the chronic hepatitis B evidence base.
Chronic hepatitis C development used Tα1 as an adjunct to interferon and pegylated interferon. The Andreone et al. 2004 J Viral Hep RCT 13 tested Tα1 plus standard IFN in treatment-naive HCV patients. The Poo et al. 2008 triple-therapy trial 14 combined thymalfasin with peginterferon alfa-2a and ribavirin. The Ciancio et al. 2012 J Viral Hep trial 15 extended the indication to peginterferon-ribavirin nonresponders.
Regulatory approvals as Zadaxin (thymalfasin) accumulated through the late 1990s and 2000s in approximately 30 countries, principally Italy, China, and other Asian and European jurisdictions where chronic hepatitis B remains a major public-health concern 3116. SciClone Pharmaceuticals (the US-based commercial sponsor) did not pursue FDA approval; the US development program for chronic hepatitis B was discontinued after the Mutchnick trial.
The second major clinical-development arc is severe sepsis. The Wu et al. 2013 ETASS multicenter single-blind randomized trial 19 reported a 28-day mortality reduction with subcutaneous Tα1 (1.6 mg twice daily) versus standard care in adults with severe sepsis. Subsequent systematic reviews and meta-analyses 202122 have been broadly supportive of the mortality signal, with the 2025 Gu et al. meta-analysis integrating the larger published trial set.
Oncology evidence includes a large randomized phase 3 trial in metastatic melanoma comparing Tα1, interferon alfa, and the combination with dacarbazine 27, a preclinical mechanistic study in NSCLC 28, the historical oncology synthesis by Garaci and colleagues 30, and a multicenter Chinese RCT protocol for HBV-related hepatocellular carcinoma after curative resection 29. Vaccine-adjuvant work in influenza and hepatitis B vaccination of immunocompromised patients is summarized by Tuthill and Camerini 34.
COVID-19 evidence emerged in 2020 from Chinese hospitals. The Liu et al. 2020 Clinical Infectious Diseases report 23 described 28-day mortality reduction in critically ill COVID-19 patients with low baseline CD8+ T-cell counts. Multicenter retrospective and cohort data 2425 reinforced the signal but did not produce a randomized phase 3 trial. The 2022 Zhang mechanism paper 26 proposed a direct antiviral entry-modulation mechanism via ACE/ACE2 downregulation.
Timeline
Thymosin Alpha-1 / Thymalin Timeline
1972Goldstein and colleagues publish purification and biological activity of 'thymosin' from bovine thymus in PNAS, the foundation of the thymic peptide field 1
1977Amino-acid sequence of thymosin alpha-1 determined; chemical synthesis follows shortly thereafter, enabling synthetic (non-bovine) supply 32
1979Low, Thurman, and colleagues publish thymosin family fractionation in Annals of the New York Academy of Sciences, establishes Tα1 as the most active component of bovine Fraction 5 2
1996Andreone et al 9. (Hepatology), RCT of thymosin alpha-1 vs interferon alfa in HBeAg-positive chronic hepatitis B; comparable virologic response with better tolerability
1998Gramenzi et al 17. (BioDrugs), early clinical pharmacology and antiviral applications review
1999Mutchnick et al 10. (J Viral Hep), multicenter phase III placebo-controlled trial of thymosin alpha-1 in chronic hepatitis B
2001Ancell et al 18. (Am J Health Syst Pharm) publish a clinician-facing thymosin alpha-1 review
2004Andreone et al. (J Viral Hep), Tα1 plus interferon alfa in treatment-naive chronic hepatitis C; Romani et al 135. (Blood) characterize Tα1 dendritic-cell activation via Toll-like receptor signaling
2006Romani et al 6. (Blood), Tα1 activates dendritic-cell tryptophan catabolism, establishing a regulatory environment balancing inflammation and tolerance
2007Goldstein historical review and Garaci historical overview (Annals NYAS) consolidate the thymosin discovery arc; Romani et al 437. publish the 'endogenous regulator' framework
2008Yang et al. (Antiviral Res) meta-analysis, Tα1 vs interferon alfa in chronic hepatitis B; Poo et al 1114. (Annals Hep) triple-therapy trial in HCV
2009Zhang et al 12. (Virol J), lamivudine plus Tα1 for HBeAg-positive chronic hepatitis B
2010Maio et al. (J Clin Oncol), large randomized trial of thymosin alpha-1, interferon alfa, and the combination with dacarbazine in metastatic melanoma; Perruccio et al 273516. (NYAS), Tα1 for immune reconstitution after haploidentical HSCT; Ciancio and Rizzetto review thymalfasin in hepatitis B/C
2012Ciancio et al 15. (J Viral Hep), Tα1 plus peginterferon-ribavirin in HCV nonresponders; Tuthill et al 34. (NYAS) summarize Tα1 as a vaccine-response enhancer
2013Wu et al 19. publish the ETASS multicenter randomized controlled trial of thymosin alpha-1 for severe sepsis in Critical Care, 28-day mortality signal
2015Garaci, Pica, Matteucci, Gaziano publish historical oncology review; Camerini and Garaci publish historical infectious-diseases review; King and Tuthill publish preclinical evaluation in immune-suppressing indications 30313229
2016Wang et al 2021. (BMC Infect Dis) and Liu et al 33. (BMC Infect Dis) publish systematic reviews and meta-analyses of Tα1 in sepsis; King and Tuthill publish 'Immune Modulation with Thymosin Alpha 1' review in Vitamins and Hormones
2018Stincardini et al 8. (Expert Opin Biol Ther), Tα1 and cellular proteostasis: a new mechanistic twist
2020Liu et al. (Clin Infect Dis) report Tα1 reduces mortality in critical COVID-19 patients with low baseline CD8+ counts; Yang et al 2328. (Biomed Pharmacother) demonstrate Tα1 blocks MDSC accumulation in NSCLC by inhibiting VEGF
2021Sun et al. (Int Immunopharmacol), multicenter retrospective study of Tα1 effect on mortality in critical COVID-19; Matteucci et al 2425. (Open Forum Infect Dis), Tα1 mitigates cytokine storm in COVID-19 blood cells
2022Zhang et al 26. (Front Biosci Landmark), Tα1 binds ACE and downregulates ACE2 expression in human respiratory epithelia
2023FDA Pharmacy Compounding Advisory Committee evaluation places thymosin alpha-1 in Category 2 on the 503A bulk-drug-substances list, substance ineligible for 503A patient-specific compounding pending further data; Quagliata et al 373836. publish patent landscape of thymosin peptides
2025Gu et al 22. (Front Cell Infect Microbiol) publish updated systematic review and meta-analysis of Tα1 efficacy in sepsis across the expanded RCT corpus
Clinical contexts studied
Clinical Contexts for Thymosin Alpha-1 / Thymalin
Chronic hepatitis B (in countries where Zadaxin is approved) well studied
Well-studied indication outside the United States; Zadaxin is marketed in approximately 30 countries including Italy and China. Not an FDA-approved indication in the US.
Randomized controlled trials in HBeAg-positive chronic hepatitis B demonstrated virologic response rates with Tα1 monotherapy comparable to interferon alfa, with substantially better tolerability 9. The Mutchnick et al. multicenter phase III placebo-controlled trial reported a sustained virologic response advantage 10. Combination with lamivudine in HBeAg-positive patients reported improved HBeAg seroconversion and HBV DNA suppression 12. The Yang et al. meta-analysis pooled efficacy across the Tα1-vs-IFN-alfa RCT corpus and reported a sustained response advantage for Tα1 11. Approval in international jurisdictions is supported by this evidence base 3116.
Chronic hepatitis C (combination with interferon-based regimens, in countries where Zadaxin is approved) well studied
Studied in randomized trials in combination with interferon and pegylated interferon plus ribavirin. International approval in selected jurisdictions; not an FDA-approved indication.
Tα1 has been studied as an adjunct to standard-of-care interferon-based regimens. Andreone et al. randomized treatment-naive chronic HCV patients to Tα1 plus IFN-alfa vs IFN-alfa alone 13. Poo et al. evaluated triple therapy (thymalfasin + peginterferon alfa-2a + ribavirin) in difficult-to-treat HCV 14. Ciancio et al. extended the indication to peginterferon-ribavirin nonresponders 15. The 2010 Ciancio-Rizzetto review summarizes the hepatitis B and C evidence base 16. Note that the introduction of direct-acting antiviral regimens for HCV from 2013 onward has substantially superseded interferon-based regimens; Tα1's role in modern HCV management is limited.
Severe sepsis (adjunct to standard care, in countries where Zadaxin is approved or used off-label) well studied
Studied in the multicenter ETASS RCT and multiple meta-analyses; mortality signal reproducible across pooled data. Not an FDA-approved indication.
The Wu et al. (2013) ETASS multicenter single-blind randomized trial randomized 361 adults with severe sepsis to subcutaneous thymosin alpha-1 (1.6 mg twice daily for 7 days) versus standard care; 28-day mortality was lower in the Tα1 arm 19. Subsequent meta-analyses by Wang et al. 20 (Tα1 plus ulinastatin), Liu et al. 21 (Tα1 alone, BMC Infect Dis), and the updated Gu et al. 2025 systematic review and meta-analysis 22 have been broadly supportive of the mortality signal, though heterogeneity in standard-care comparators and trial geography limits confidence in generalization to contemporary critical-care settings outside the source population.
Severe COVID-19 (during the early SARS-CoV-2 pandemic) emerging
Studied principally in Chinese retrospective and prospective cohort data published in 2020-2022; encouraging mortality signal in patients with low baseline CD8+ counts, but evidence is largely non-randomized and not generalizable to current variants or contemporaneous standard-of-care.
Liu et al. (Clin Infect Dis 2020) reported that thymosin alpha-1 restored lymphocyte counts and reduced 28-day mortality in critically ill COVID-19 patients, particularly those with low baseline CD8+ counts 23. A multicenter retrospective analysis 24 reported a mortality reduction in a larger cohort of critically ill patients. In vitro work demonstrated Tα1 mitigation of cytokine storm in COVID-19 patient blood cells 25, and a 2022 mechanistic paper proposed Tα1 binding to ACE with downregulation of ACE2 expression in respiratory epithelia as a complementary antiviral entry mechanism 26. The evidence is encouraging but the trial designs were largely retrospective, the standard-of-care comparators predate antiviral and immunomodulatory advances, and SARS-CoV-2 variants have evolved.
Metastatic melanoma (adjunct to dacarbazine, in international clinical research) well studied
Studied in a large randomized phase 3 trial in combination with dacarbazine and interferon alfa.
The Maio et al. (J Clin Oncol 2010) phase 3 randomized trial enrolled 488 patients with metastatic melanoma to thymosin alpha-1 plus dacarbazine, interferon alfa plus dacarbazine, the triple combination, or dacarbazine alone 27. Tα1-containing arms reported a numerical overall-survival advantage over dacarbazine monotherapy, though the trial did not change clinical practice and modern melanoma care is dominated by checkpoint inhibitors and targeted therapy. Preclinical models supporting the immune-modulation rationale are summarized by King and Tuthill 32 and the historical oncology review by Garaci and colleagues 30.
HBV-related hepatocellular carcinoma (adjuvant after curative resection, in Chinese clinical research) emerging
Studied in a multicenter Chinese randomized protocol.
Qiu et al. (2015) published the protocol for a multicenter Chinese RCT evaluating thymalfasin adjuvant therapy after curative resection of HBV-related hepatocellular carcinoma 29. The rationale combines the established Zadaxin antiviral role in chronic hepatitis B with the postoperative immune-modulation hypothesis for HCC recurrence prevention. Long-term outcomes from the trial are not yet integrated into international HCC guidelines.
Non-small cell lung cancer (preclinical and exploratory clinical research) emerging
Preclinical mechanistic evidence in tumor-microenvironment models; clinical evidence base is heterogeneous and not practice-changing.
Yang et al. (2020) demonstrated that Tα1 blocks myeloid-derived suppressor-cell accumulation in NSCLC murine models by inhibiting VEGF production 28, offering a tumor-microenvironment rationale for the adjuvant-immunotherapy hypothesis. Clinical evidence is heterogeneous and does not support a defined role in NSCLC management outside of investigational protocols.
Vaccine adjuvant in immunocompromised patients (influenza and hepatitis B vaccination) emerging
Studied in small trials and reviews; rationale supported by mechanistic dendritic-cell biology. International use, not an FDA-approved indication.
Tuthill et al. (2012) summarize the evidence base for Tα1 as a vaccine-response enhancer, principally for influenza and hepatitis B vaccination in elderly and hemodialysis populations with blunted vaccine responses 34. The Romani group's mechanistic dendritic-cell work 57 provides a coherent rationale. Trial sizes are small and the evidence base has not produced a regulatory adjuvant designation in any jurisdiction.
Immune reconstitution after haploidentical hematopoietic stem cell transplantation emerging
Studied in single-center European cohort data.
Perruccio et al. (2010) reported that Tα1 administration after T-cell-depleted haploidentical HSCT was associated with accelerated post-transplant immune reconstitution and reduced infection-related mortality 35. The work extends the Romani-group dendritic-cell biology into the post-transplant clinical setting. Phase 3 trial data are not available.
Off-label use
Off-Label Uses of Thymosin Alpha-1 / Thymalin
General 'immune support' marketing (US wellness and longevity clinic context) emerging
Evidence should be interpreted in context for thymosin alpha-1. Any patient-specific request requires prescriber rationale and pharmacy review; availability is determined case by case.
Evidence should be interpreted in context for thymosin alpha-1. Any patient-specific request requires prescriber rationale and pharmacy review; availability is determined case by case.3738
Compounded use
Compounded Thymosin Alpha-1 / Thymalin (503A)
Physicians may submit patient-specific prescription requests for pharmacy review. For thymosin alpha-1, certain preparations may be available now when clinically appropriate, lawfully prescribed, and approved by the dispensing pharmacy. Availability is determined case by case and may depend on patient-specific documentation, ingredient status, source qualification, formulation feasibility, state requirements, and pharmacist judgment. The review starts with the evidence constraint: The evidence base for thymosin alpha-1 is broader than many Category 2 peptides because Zadaxin and related thymalfasin products have been studied and used abroad. That international record does not create an FDA-approved US product or automatic 503A availability.
This ingredient is part of an evolving FDA review process. RonanRx is monitoring FDA's PCAC process and any subsequent agency action. This ingredient is part of an evolving FDA review process for peptide-related bulk substances used in compounding. Availability may change after FDA review, PCAC discussion, final agency action, or state-board guidance. For thymosin alpha-1, RonanRx ties that monitoring to the evidence limits described above and to any patient-specific documentation submitted by the prescriber.
Valid patient-specific prescription required. Supporting clinical rationale may be requested. Compounded medications are not FDA-approved. No consumer self-ordering, no office stock, no bulk dispensing. Requests for thymosin alpha-1 are reviewed before any preparation is made or released. The regulated US route is not a wellness-clinic immune peptide protocol. A prescriber may submit a patient-specific request, and RonanRx reviews the clinical rationale, product identity, source documentation, and regulatory posture before any dispensing decision.
Formulations and routes
Thymosin Alpha-1 / Thymalin Formulations and Routes
Form
Concentration
Description
Sterile lyophilized powder for reconstitution (international reference product)
1.6 mg per vial, reconstituted with 1 mL sterile water for injection prior to subcutaneous administration
Zadaxin (SciClone Pharmaceuticals) is the international reference product. Supplied as a sterile lyophilized white powder in a single-use vial; reconstituted immediately before administration. Approved in approximately 30 countries; NOT FDA-approved in the United States.1831
RonanRx-compounded preparation
—
If a patient-specific thymosin alpha-1 request is approved after pharmacy review, the route and formulation must be selected by the prescriber and dispensing pharmacy for that named patient. Research-use presentations sold online are not RonanRx preparations.3738
Routes used in published literature: subcutaneous.
Dosing
Thymosin Alpha-1 / Thymalin Dosing
Route
Population
Range
Duration
Study type
Subcutaneous
Chronic hepatitis B (Zadaxin international labeling)
1.6 mg twice weekly for 6 months
26 weeks (typical international labeled course)
Labeled regimen in international approvals; supported by RCTs91018
Subcutaneous
Chronic hepatitis C (combination with peginterferon alfa-2a and ribavirin, international clinical use)
1.6 mg twice weekly for 24-48 weeks alongside the interferon-based regimen
Internationally, the labeled Zadaxin regimen for chronic hepatitis B is 1.6 mg subcutaneously twice weekly for 6 months; for chronic hepatitis C, the same per-dose unit is given twice weekly alongside the interferon-based backbone for the duration of that regimen 1831. The ETASS sepsis trial protocol used 1.6 mg twice daily for 7 days 19. These regimens are derived from international clinical trials and approvals; they are not FDA-labeled in the US.
RonanRx does not publish a consumer dosing schedule for thymosin alpha-1. Any request requires a valid patient-specific prescription, supporting clinical rationale, and pharmacist review. Route, strength, dosing interval, monitoring expectations, and dispensing quantity would be determined case by case from the prescriber's documentation and pharmacy feasibility review.
Doses listed are literature context, not patient instructions. Dosing decisions are made by the prescribing doctor and tailored to the individual patient.
Safety
Thymosin Alpha-1 / Thymalin Safety
Safety overview
Across more than three decades of international clinical use, thymosin alpha-1 has shown a favorable tolerability profile 38. The Andreone et al. 1996 Hepatology RCT specifically noted substantially better tolerability for Tα1 than for interferon alfa 9. The Mutchnick et al. multicenter phase III trial reported no treatment-related discontinuations and an adverse-event profile not significantly different from placebo 10. The Wu et al. ETASS sepsis trial similarly reported no major safety signal beyond background ICU adverse events 19. Practice-facing reviews 183331 consistently describe Tα1 as well tolerated; injection-site reactions (transient erythema and discomfort) are the most common reported event.
Hypersensitivity to thymosin alpha-1 or to excipients in international reference products is the principal contraindication in approved jurisdictions 1838. Use in pregnancy and lactation has not been adequately studied; international labels generally advise against use during pregnancy in the absence of compelling clinical need.
The safety profile summarized here applies to international reference product (Zadaxin) used at labeled doses. It does not apply to US wellness-clinic preparations of uncertain identity, potency, sterility, or endotoxin status. Substances sold as 'thymosin alpha-1' outside the regulated supply chain are not characterized by published safety data and are not endorsed by RonanRx 3738. Any RonanRx availability decision is made case by case after patient-specific pharmacy review.
Contraindications
International Zadaxin labeling identifies known hypersensitivity to thymosin alpha-1 or to excipients in the product as a contraindication 18. Use in pregnancy and lactation has not been adequately studied and is generally not recommended in approved jurisdictions in the absence of compelling clinical need. Use in immunosuppressed transplant recipients on cyclosporine-based regimens has been studied 35 but should be coordinated with the transplant team.
Because Physicians may submit patient-specific prescription requests for pharmacy review. Availability is determined case by case.
Drug interactions
Thymosin alpha-1 is a peptide cleared by proteolytic catabolism and does not participate in cytochrome P450-mediated drug interactions 121923. In published clinical use, Tα1 has been combined with interferon alfa, pegylated interferon, ribavirin, lamivudine, dacarbazine, and standard sepsis or COVID-19 supportive care without notable pharmacokinetic interaction signals 131427.
Because the substance is on FDA Category 2 and is not compounded by RonanRx 3738, a RonanRx-product-specific drug-interaction profile is not applicable.
Adverse events
The most commonly reported adverse events across international clinical trials of thymosin alpha-1 are transient injection-site reactions (erythema, mild discomfort) 9101838. No consistent systemic adverse-event signal has emerged across more than 30 years of clinical use. The Mutchnick et al. phase III trial reported no statistically significant difference in adverse-event rates between Tα1 and placebo 10. The ETASS sepsis trial reported no Tα1-specific safety signal beyond background critical-care adverse events 19. Meta-analytic synthesis 112122 is consistent with this profile.
Adverse-event surveillance for US wellness-clinic preparations of 'thymosin alpha-1' is not systematically conducted. Reports of adverse events temporally associated with such preparations should be filed with FDA's MedWatch program. For any physician-submitted RonanRx request, adverse-event expectations and follow-up would be reviewed case by case before dispensing 3738.
Monitoring
Monitoring Thymosin Alpha-1 / Thymalin Therapy
No RonanRx-specific monitoring protocol has been established for thymosin alpha-1. If a patient-specific prescription is submitted, supporting clinical rationale may be requested, and monitoring expectations would be reviewed case by case against the published evidence, route, sterile or nonsterile status, concomitant therapies, and patient risk factors.
For US patients asking about thymosin alpha-1 from wellness clinics, clinicians should be aware of the FDA Category 2 designation 3738 and the absence of US FDA-supervised pharmacovigilance for non-approved preparations.
Special populations
Thymosin Alpha-1 / Thymalin in Special Populations
Pregnancy
No FDA-recognized use guidance for thymosin alpha-1 in this population is established. Any patient-specific request would require prescriber rationale, patient-specific risk review, and pharmacist approval before dispensing.
Lactation
There are no human data on the presence of thymosin alpha-1 in human milk or its effects on the breastfed infant. International labeling advises against use during lactation in the absence of compelling clinical need 18.
Pediatric
Safety and effectiveness in pediatric patients have not been established. Pediatric data are limited to small studies in chronic viral hepatitis and in pediatric oncology and HSCT settings, principally outside the United States.
Geriatric
Tα1 has been studied in older adult populations, particularly in chronic hepatitis B and C trials and in influenza vaccine adjuvant work 34. No specific age-related dose adjustment is reflected in international labeling 18.
Renal impairment
Thymosin alpha-1 is a small peptide cleared by proteolytic catabolism; renal clearance is a minor pathway. International labeling does not require a renal dose adjustment 18. The vaccine-adjuvant evidence base includes hemodialysis populations 34.
Hepatic impairment
Thymosin alpha-1 has been studied extensively in chronic hepatitis B and C populations with varying degrees of compensated hepatic dysfunction 91013. International labeling does not require a hepatic-function-based dose adjustment 15.
Evidence quality
Thymosin Alpha-1 / Thymalin Evidence Quality
The international evidence base for thymosin alpha-1 is substantial and predates most of the modern peptide-therapy landscape. Randomized controlled trials in chronic hepatitis B 91012 supported international Zadaxin approvals in approximately 30 countries, with meta-analytic synthesis confirming a sustained virologic response advantage over interferon alfa 11. The chronic hepatitis C evidence base 131415 is now of historical interest given the dominance of direct-acting antivirals from 2013 onward. The severe-sepsis evidence base centered on the ETASS multicenter RCT 19 is reinforced by multiple systematic reviews and meta-analyses 202122 with a reproducible mortality signal, though heterogeneity in standard-care comparators and trial geography (predominantly Chinese ICUs) limits generalization.
Oncology evidence comprises the Maio et al. (2010) melanoma phase 3 trial 27 (not practice-changing in the modern checkpoint-inhibitor era), the Qiu et al. (2015) Chinese HCC adjuvant protocol 29, and preclinical NSCLC mechanism work 28. COVID-19 evidence is largely retrospective and not generalizable to current variants 2324. Mechanistic work by the Romani group 567 and others 826 is internally coherent and supports the immune-modulation framework.
From a US regulatory standpoint, the FDA Pharmacy Compounding Advisory Committee placed thymosin alpha-1 in Category 2 of the 503A bulk-drug-substances list 3738, i.e., insufficient information to evaluate for use in compounding. This designation reflects the absence of FDA-supervised efficacy and safety review of US-marketed material, not a finding of harm. The international evidence base may be adequate to support an eventual FDA reclassification request, but at the time of this writing thymosin alpha-1 may not be used in 503A patient-specific compounding. RonanRx does not source, compound, or dispense the substance.
Major studies
Major Thymosin Alpha-1 / Thymalin Clinical Studies
Randomized open-label trial in treatment-naive chronic hepatitis C adults
—
48 weeks treatment + 24 weeks follow-up
Combination of thymosin alpha-1 with interferon alfa improved end-of-treatment and sustained virologic response over interferon alfa alone in this naive population 13
Randomized open-label triple-therapy study in genotype 1 chronic hepatitis C
—
48 weeks treatment
Addition of thymalfasin to peginterferon alfa-2a plus ribavirin improved end-of-treatment and sustained virologic response in difficult-to-treat HCV 14
Multicenter randomized open-label trial in chronic hepatitis C patients not responsive to prior peginterferon-ribavirin
—
48 weeks
Addition of thymosin alpha-1 to retreatment with peginterferon alfa-2a plus ribavirin produced modest improvement in sustained virologic response in this difficult population 15
Multicenter single-blind randomized controlled trial in adults with severe sepsis
361
7-day intervention, 28-day mortality endpoint
Subcutaneous thymosin alpha-1 (1.6 mg twice daily for 7 days) plus standard care reduced 28-day all-cause mortality compared with standard care alone in adults with severe sepsis 19
Phase 3 randomized open-label trial of thymosin alpha-1, interferon alfa, and the combination with dacarbazine in metastatic melanoma
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Tα1-containing arms reported a numerical overall-survival advantage over dacarbazine monotherapy; trial did not change clinical practice 27. Modern melanoma care is dominated by checkpoint inhibitors and targeted therapy
Preclinical mechanistic study of dendritic-cell tryptophan catabolism downstream of Tα1 signaling
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Tα1 activates dendritic-cell tryptophan catabolism via indoleamine 2,3-dioxygenase, establishing a regulatory cytokine milieu that balances inflammation and tolerance 6
Protocol publication for a multicenter Chinese RCT of thymalfasin adjuvant therapy in HBV-related hepatocellular carcinoma after curative resection
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Protocol establishes the rationale and analytic framework for evaluating Tα1 as an adjunct after HCC resection in HBV-endemic populations 29
Mechanism detail
Detailed Mechanism of Thymosin Alpha-1 / Thymalin
The molecular mechanism of thymosin alpha-1 begins at the dendritic cell. The seminal Romani et al. 2004 Blood paper 5 used MyD88-knockout mice and TLR-specific blockade to demonstrate that Tα1 signaling in dendritic cells is TLR-dependent, with the strongest signal through TLR-9 in plasmacytoid DCs and TLR-2 in conventional DCs. Engagement drives a Th1 cytokine profile (IL-12, IFN-γ) and antifungal resistance in murine models of invasive aspergillosis. The Romani 2006 Blood follow-up 6 characterized a parallel effect: Tα1 induces IDO-mediated tryptophan catabolism in dendritic cells, producing kynurenines that establish a tolerogenic regulatory environment. This dual capacity, proinflammatory Th1 priming and concurrent IDO-driven regulatory balance, underlies the description of Tα1 as an 'endogenous regulator of inflammation, immunity, and tolerance' 7.
Downstream on T-cells, Tα1 promotes maturation of CD4−/CD8− thymocyte precursors toward functional CD4+ and CD8+ phenotypes, upregulates CD3 and CD25 (IL-2 receptor alpha) expression, and increases IL-2 and IFN-γ production in stimulated lymphocytes. In severely immunocompromised states, including critical illness with lymphocytopenia, post-chemotherapy myelosuppression, and chronic viral infection, Tα1 partially restores absolute lymphocyte counts and reverses markers of T-cell exhaustion such as PD-1 and Tim-3 expression 23. On natural killer cells, Tα1 augments cytotoxicity and IFN-γ production; on macrophages and monocytes, it enhances chemotaxis and antimicrobial function.
Cellular proteostasis work extends the mechanism beyond classical immunology. Stincardini et al. (2018) characterized Tα1 as a regulator of autophagy and the unfolded protein response, with implications for chronic inflammatory and infectious-disease pathways 8. In the SARS-CoV-2 setting, mechanistic work has examined Tα1 binding to angiotensin-converting enzyme and downregulation of ACE2 expression in respiratory epithelial cells 26, proposing a direct antiviral entry-modulation mechanism complementary to the immunomodulatory effect. In oncology contexts, Tα1 has been shown to suppress myeloid-derived suppressor-cell accumulation in NSCLC models via VEGF inhibition 28, offering a tumor-microenvironment rationale for the adjuvant signals reported in cancer trials.
Thymosin alpha-1 administered subcutaneously is rapidly absorbed; reported terminal half-life is approximately 2 hours in healthy adults 18. The peptide is cleared by proteolytic catabolism; renal clearance is a minor pathway. Cytochrome P450 metabolism is not relevant for a small linear peptide. PK characteristics are reproducible across age and renal-function strata in published international clinical use 1817.
PK characterization for a RonanRx preparation would depend on the actual formulation, route, and patient-specific prescription reviewed by the pharmacy. International Zadaxin data and US wellness-clinic preparations are not interchangeable with a RonanRx-compounded preparation 3738.
Pharmacodynamics
Pharmacodynamic effects of thymosin alpha-1 are measurable as changes in T-cell subset distribution and function (CD4+ and CD8+ counts, CD3 and CD25 expression, IL-2 and IFN-γ production), natural-killer-cell cytotoxicity, dendritic-cell maturation marker expression (CD83, HLA-DR), and Th1 cytokine output 5633. In severely immunocompromised states such as critical illness with lymphocytopenia, Tα1 partially restores absolute lymphocyte counts and reverses T-cell exhaustion markers (PD-1, Tim-3) 23.
Indication-specific endpoints include HBV DNA suppression and HBeAg seroconversion for chronic hepatitis B 910, HCV RNA clearance for chronic hepatitis C 1314, 28-day all-cause mortality for severe sepsis 19, and overall survival in oncology trials 27.
Zadaxin (SciClone Pharmaceuticals) is the international reference product, a sterile lyophilized powder for reconstitution, supplied at 1.6 mg per single-use vial. Zadaxin holds regulatory approval in approximately 30 countries (including Italy and China) for chronic hepatitis B, chronic hepatitis C, and as a vaccine adjuvant in immunocompromised patients 311618. NOT FDA-approved in the United States.
If a thymosin alpha-1 preparation is approved after pharmacy review, RonanRx applies source documentation, formulation records, lot traceability, release checks, and storage controls appropriate to the actual dosage form. Research-use vial storage practices do not substitute for pharmacy-assigned storage, beyond-use dating, sterility controls when applicable, or recallable batch records.
Storage
Thymosin Alpha-1 / Thymalin Storage and Handling
If a thymosin alpha-1 preparation is approved after pharmacy review, RonanRx applies source documentation, formulation records, lot traceability, release checks, and storage controls appropriate to the actual dosage form. Research-use vial storage practices do not substitute for pharmacy-assigned storage, beyond-use dating, sterility controls when applicable, or recallable batch records.
Physicians may submit patient-specific prescription requests for pharmacy review. For thymosin alpha-1, certain preparations may be available now when clinically appropriate, lawfully prescribed, and approved by the dispensing pharmacy. Availability is determined case by case and may depend on patient-specific documentation, ingredient status, source qualification, formulation feasibility, state requirements, and pharmacist judgment. The review starts with the evidence constraint: The evidence base for thymosin alpha-1 is broader than many Category 2 peptides because Zadaxin and related thymalfasin products have been studied and used abroad. That international record does not create an FDA-approved US product or automatic 503A availability.
This ingredient is part of an evolving FDA review process. RonanRx is monitoring FDA's PCAC process and any subsequent agency action. This ingredient is part of an evolving FDA review process for peptide-related bulk substances used in compounding. Availability may change after FDA review, PCAC discussion, final agency action, or state-board guidance. For thymosin alpha-1, RonanRx ties that monitoring to the evidence limits described above and to any patient-specific documentation submitted by the prescriber.
Valid patient-specific prescription required. Supporting clinical rationale may be requested. Compounded medications are not FDA-approved. No consumer self-ordering, no office stock, no bulk dispensing. Requests for thymosin alpha-1 are reviewed before any preparation is made or released. The regulated US route is not a wellness-clinic immune peptide protocol. A prescriber may submit a patient-specific request, and RonanRx reviews the clinical rationale, product identity, source documentation, and regulatory posture before any dispensing decision.
Pharmacist review
For thymosin alpha-1, the pharmacist review starts before any preparation is made. Valid patient-specific prescription required. Supporting clinical rationale may be requested. The pharmacist reviews ingredient status, sourcing, formulation feasibility, state requirements, patient-specific documentation, and whether dispensing is appropriate case by case.
Quality and traceability
If a thymosin alpha-1 preparation is approved after pharmacy review, RonanRx applies source documentation, formulation records, lot traceability, release checks, and storage controls appropriate to the actual dosage form. Research-use vial storage practices do not substitute for pharmacy-assigned storage, beyond-use dating, sterility controls when applicable, or recallable batch records. The patient-specific framework and quality controls are documented in the cited compounding references 41.
Cold chain
If a thymosin alpha-1 preparation is approved after pharmacy review, RonanRx applies source documentation, formulation records, lot traceability, release checks, and storage controls appropriate to the actual dosage form. Research-use vial storage practices do not substitute for pharmacy-assigned storage, beyond-use dating, sterility controls when applicable, or recallable batch records.
FAQ
Frequently Asked Questions About Thymosin Alpha-1 / Thymalin
Can physicians request thymosin alpha-1 through RonanRx?
Physicians may submit patient-specific prescription requests for pharmacy review. Certain preparations may be available now when clinically appropriate, lawfully prescribed, and approved by the dispensing pharmacy. Availability is determined case by case. Compounded medications are not FDA-approved, and no consumer self-ordering, office stock, or bulk dispensing is offered.3738
Is thymosin alpha-1 approved anywhere?
Yes, internationally. Thymosin alpha-1 is the active ingredient of Zadaxin (thymalfasin), marketed by SciClone Pharmaceuticals and approved in approximately 30 countries (including Italy and China) for chronic hepatitis B, chronic hepatitis C, and as a vaccine adjuvant in immunocompromised patients 3116. It is NOT FDA-approved for any use in the United States.
What is the evidence base?
There is a substantial international evidence base 27. Randomized controlled trials and meta-analyses support efficacy in chronic hepatitis B (Andreone 1996, Mutchnick 1999, Yang 2008 meta-analysis), chronic hepatitis C in combination with interferon-based regimens (Andreone 2004, Poo 2008, Ciancio 2012), and severe sepsis (Wu 2013 ETASS, multiple meta-analyses including Gu 2025) 91011. COVID-19 and oncology evidence is encouraging but largely retrospective or single-trial 192223.
How does thymosin alpha-1 work?
Thymosin alpha-1 is an immune modulator 33. It activates dendritic cells through Toll-like receptor signaling (principally TLR-9 and TLR-2), promotes T-cell maturation and natural-killer-cell activity, and concurrently engages indoleamine 2,3-dioxygenase-mediated tryptophan catabolism that establishes a regulatory cytokine environment 56. Net effect is enhanced Th1 immunity balanced by regulatory tone, a profile that fits the chronic viral infection, sepsis, and adjunct-immunotherapy contexts where it has been studied 7.
What about wellness-clinic 'thymosin alpha-1' available in the United States?
Material sold as 'thymosin alpha-1' by US wellness clinics outside the regulated supply chain is not FDA-supervised, is not characterized by published pharmacovigilance, and is not endorsed by RonanRx. The FDA Category 2 designation means the substance may not be used in 503A patient-specific compounding pending further evaluation 37. RonanRx does not source, compound, or dispense thymosin alpha-1 in any form 38.
Could RonanRx compound thymosin alpha-1 if FDA reclassifies it to Category 1?
RonanRx would re-evaluate at that point. Reclassification would remove the regulatory bar, but additional pharmacy-side prerequisites would still need to be met: pharmaceutical-grade active ingredient with documented identity, potency, sterility, and endotoxin specifications; USP <797> sterile-compounding workflow; documented patient-specific clinical rationale under section 503A; and a defensible US clinical-evidence basis for the prescribed regimen 3739. The international Zadaxin evidence base would inform but not by itself satisfy the evaluation 40.
Where can patients get Zadaxin if they want it?
Patients seeking Zadaxin in jurisdictions where it is approved should consult prescribers and pharmacies licensed in those jurisdictions. Thymalfasin (Zadaxin) is sold internationally by SciClone Pharmaceuticals; it is not available through US compounding pharmacies, and RonanRx does not source it 3116.
Clinician resource
Download the Thymosin Alpha-1 / Thymalin Clinical Monograph (PDF)
The full white paper covers every section on this page plus chemical identity, evidence grading, indication-by-indication summaries, research gaps, and reference appendix. Suitable for sharing with prescribing doctors and pharmacist reviewers.
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[low1979] Low TL, Thurman GB, Chincarini C, McClure JE, Marshall GD, Hu SK, Goldstein AL. Current status of thymosin research: evidence for the existence of a family of thymic factors that control T-cell maturation. Annals of the New York Academy of Sciences. 1979. PMID 394636. (accessed 2026-05-11)
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[romani2004_dc_tlr] Romani L, Bistoni F, Gaziano R, Bozza S, Montagnoli C, Perruccio K, Pitzurra L, Bellocchio S, Velardi A, Rasi G, Di Francesco P, Garaci E. Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling. Blood. 2004. PMID 14982877. (accessed 2026-05-11)
[romani2006_dc_ido] Romani L, Bistoni F, Perruccio K, Montagnoli C, Gaziano R, Bozza S, Bonifazi P, Bistoni G, Rasi G, Velardi A, Fallarino F, Garaci E, Puccetti P. Thymosin alpha1 activates dendritic cell tryptophan catabolism and establishes a regulatory environment for balance of inflammation and tolerance. Blood. 2006. PMID 16741252. (accessed 2026-05-11)
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[mutchnick1999] Mutchnick MG, Lindsay KL, Schiff ER, Cummings GD, Appelman HD, Peleman RR, Silva M, Roach KC, Simmons F, Milstein S, Gordon SC, Ehrinpreis MN. Thymosin alpha1 treatment of chronic hepatitis B: results of a phase III multicentre, randomized, double-blind and placebo-controlled study. Journal of Viral Hepatitis. 1999. PMID 10607256. (accessed 2026-05-11)
[yang2008_hbv_meta] Yang YF, Zhao W, Zhong YD, Yang YJ, Shen L, Zhang N, Huang P. Comparison of the efficacy of thymosin alpha-1 and interferon alpha in the treatment of chronic hepatitis B: a meta-analysis. Antiviral Research. 2008. PMID 18078676. (accessed 2026-05-11)
[zhang2009_lam_combo] Zhang YY, Chen EQ, Yang J, Duan YR, Tang H. Treatment with lamivudine versus lamivudine and thymosin alpha-1 for e antigen-positive chronic hepatitis B patients: a meta-analysis. Virology Journal. 2009. PMID 19467157. (accessed 2026-05-11)
[andreone2004_hcv] Andreone P, Gramenzi A, Cursaro C, Felline F, Loggi E, Margotti M, Biselli M, Lorenzini S, Bernardi M. Thymosin-alpha 1 plus interferon-alpha for naive patients with chronic hepatitis C: results of a randomized controlled pilot trial. Journal of Viral Hepatitis. 2004. PMID 14738560. (accessed 2026-05-11)
[poo2008_triple] Poo JL, Sánchez Avila F, Kershenobich D, García Samper X, Torres-Ibarra R, Góngora J, Cano C, Parana R, Wiltzer R, Uribe M. Efficacy of triple therapy with thymalfasin, peginterferon alpha-2a, and ribavirin for the treatment of hispanic chronic HCV nonresponders. Annals of Hepatology. 2008. PMID 19034238. (accessed 2026-05-11)
[ciancio2012_hcv] Ciancio A, Andreone P, Kaiser S, Mangia A, Milella M, Sola R, Pol S, Tsianos E, Boccato S, Pessôa M, Rizzetto M. Thymosin alpha-1 with peginterferon alfa-2a/ribavirin for chronic hepatitis C not responsive to IFN/ribavirin: an adjuvant role?. Journal of Viral Hepatitis. 2012. PMID 22233415. (accessed 2026-05-11)
[ciancio2010] Ciancio A, Rizzetto M. Thymalfasin in the treatment of hepatitis B and C. Annals of the New York Academy of Sciences. 2010. PMID 20536462. (accessed 2026-05-11)
[gramenzi1998_review] Gramenzi A, Cursaro C, Andreone P, Bernardi M. Thymalfasin: clinical pharmacology and antiviral applications. BioDrugs. 1998. PMID 18020580. (accessed 2026-05-11)
[ancell2001] Ancell CD, Phipps J, Young L. Thymosin alpha-1. American Journal of Health-System Pharmacy. 2001. PMID 11381492. (accessed 2026-05-11)
[wu2013_etass] Wu J, Zhou L, Liu J, Ma G, Kou Q, He Z, Chen J, Ou-Yang B, Chen M, Li Y, Wu X, Gu B, Chen L, Zou Z, Qiang X, Chen Y, Lin A, Zhang G, Guan X. The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial. Critical Care. 2013. PMID 23327199. (accessed 2026-05-11)
[wang2016_ulinastatin_meta] Wang FY, Fang B, Qiang XH, Yu TO, Zhong JR, Cao J, Chen WP. The Efficacy and Immunomodulatory Effects of Ulinastatin and Thymosin α1 for Sepsis: A Systematic Review and Meta-Analysis. BioMed Research International. 2016. PMID 27340674. (accessed 2026-05-11)
[liu2016_sepsis_meta] Liu F, Wang HM, Wang T, Zhang YM, Zhu X. The efficacy of thymosin α1 as immunomodulatory treatment for sepsis: a systematic review of randomized controlled trials. BMC Infectious Diseases. 2016. PMID 27633969. (accessed 2026-05-11)
[gu2025_sepsis_meta] Gu B, Zhou Y, Nie Y, Wang L, Liang L. Efficacy of thymosin α1 for sepsis: a systematic review and meta-analysis of randomized controlled trials. Frontiers in Cellular and Infection Microbiology. 2025. PMID 40969554. (accessed 2026-05-11)
[liu2020_covid] Liu Y, Pan Y, Hu Z, Wu M, Wang C, Feng Z, Mao C, Tan Y, Liu Y, Chen L, Li M, Wang G, Yuan Z, Diao B, Wu Y, Chen Y. Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells. Clinical Infectious Diseases. 2020. PMID 32442287. (accessed 2026-05-11)
[sun2021_covid_mortality] Sun Q, Xie J, Zheng R, Li X, Chen H, Tong Z, Pan C, Huang R, Yu W, Liu Y, Qiu H, Yang Y. The effect of thymosin α1 on mortality of critical COVID-19 patients: A multicenter retrospective study. International Immunopharmacology. 2021. PMID 33208294. (accessed 2026-05-11)
[matteucci2021_cytokine] Matteucci C, Minutolo A, Balestrieri E, Petrone V, Fanelli M, Malagnino V, Ianiro G, Sandro AD, Garaci E, Sinibaldi-Vallebona P, Andreoni M. Thymosin Alpha 1 Mitigates Cytokine Storm in Blood Cells From Coronavirus Disease 2019 Patients. Open Forum Infectious Diseases. 2021. PMID 33506065. (accessed 2026-05-11)
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[maio2010_melanoma] Maio M, Mackiewicz A, Testori A, Trefzer U, Ferraresi V, Jassem J, Garbe C, Lesimple T, Guillot B, Gascon P, Gilde K, Camerini R, Cognetti F. Large randomized study of thymosin alpha 1, interferon alfa, or both in combination with dacarbazine in patients with metastatic melanoma. Journal of Clinical Oncology. 2010. PMID 20194853. (accessed 2026-05-11)
[yang2020_nsclc_mdsc] Yang Z, Guo J, Cui K, Du Y, Zhao H, Zhu L, Weng L, Tang W, Wang L. Thymosin alpha-1 blocks the accumulation of myeloid suppressor cells in NSCLC by inhibiting VEGF production. Biomedicine & Pharmacotherapy. 2020. PMID 32942159. (accessed 2026-05-11)
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How to access
How to Access Thymosin Alpha-1 / Thymalin
Physicians may submit patient-specific prescription requests for Thymosin Alpha-1 / Thymalin for pharmacy review. Availability is determined case by case, and RonanRx is monitoring FDA's PCAC process and any subsequent agency action.
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