TA1 — Peptide Protocol Wiki reference
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Summary (generated — provider review required)
Thymosin Alpha-1: Immune Modulator Research Guide | Peptide Protocol Wiki Skip to main content 🧬 Peptide Protocol Wiki Peptides Side Effects New Learn Directory Tools Blog News About ⌘K ⌘K 🌱 New to Peptides? Start the 7-step beginner guide Peptides Side Effects New Directory Learn Tools Blog News About Thymosin Alpha-1 📋 Overview 🧬 Molecule 🔄 Similar ⚠️ Side Effects 💉 Dosing 🔬 Research 🚨 Risks 👥 Community 📊 Community Data Home Peptides Thymosin Alpha-1 Immune Support Anti-Inflammatory approved Thymosin Alpha-1 Also known as: Thymalfasin, Zadaxin, Thymosin α1 Compare with 2 peptide s Research compiled by Peptide Protocol Wiki 📅 Updated January 29, 2026 Citations Verified TL;DR Thymosin Alpha-1 is a 28-amino acid peptide naturally produced by the thymus gland, approved in over 35 countries for treatment of hepatitis B, hepatitis C, and as an immune adjuvant. It enhances T-cell maturation and function, activates dendritic cells, and modulates cytokine production.
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Linked assets (19) · phenotypes (0)
evidence_reference, safety_reference, dosing_reference, mechanism, monitoring_reference, contraindication_reference
Findings (106) · awaiting review (56)
safety · pending
Thymosin Alpha-1: Immune Modulator Research Guide | Peptide Protocol Wiki Skip to main content 🧬 Peptide Protocol Wiki Peptides Side Effects New Learn Directory Tools Blog News About ⌘K ⌘K 🌱 New to Peptides?
outcome · pending
As thymic output declines with age, the availability of endogenous Ta1 correspondingly decreases, which has been associated with age-related immunosenescence.
dosing · pending
Start the 7-step beginner guide Peptides Side Effects New Directory Learn Tools Blog News About Thymosin Alpha-1 📋 Overview 🧬 Molecule 🔄 Similar ⚠️ Side Effects 💉 Dosing 🔬 Research 🚨 Risks 👥 Community 📊 Community Data Home Peptides Thymosin Alpha-1 Immune Support Anti-Inflammatory approved Thymosin Alpha-1 Also known as: Thymalfasin, Zadaxin, Thymosin α1 Compare with 2 peptide s Research compiled by Peptide Protocol Wiki 📅 Updated January 29, 2026 Citations Verified TL;DR Thymosin Alpha-1 is a 28-amino acid peptide naturally produced by the thymus gland, approved in over 35 countries for treatment of hepatitis B, hepatitis C, and as an immune adjuvant.
mechanism · pending
It enhances T-cell maturation and function, activates dendritic cells, and modulates cytokine production.
safety · pending
Browse all immune peptides → Table of Contents 📌 TL;DR • Approved for hepatitis B treatment in multiple countries • Enhances T-cell mediated immunity • Stimulates dendritic cell maturation • Investigated as vaccine adjuvant Community-Reported Side Effects Anecdotal ?
mechanism · pending
📋 Protocol Quick-Reference Immune modulation for chronic hepatitis B, cancer adjuvant immunotherapy, and immune re
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constitution 💉 Dosing Amount 1.6 mg Frequency Twice weekly (standard); daily during chemotherapy cycles (cancer adjuvant) Duration 6-12 months (hepatitis B); 3-6 months (immune support); per chemo cycle (cancer) 💊 Administration Route SC Schedule Twice weekly (standard); daily during chemotherapy cycles (cancer adjuvant) Timing No specific time of day; maintain consistent schedule with 3-4 days between doses ✓ Rotate injection sites 📅 Cycle Duration 6-12 months (hepatitis B); 3-6 months (immune support); per chemo cycle (cancer) Repeatable Yes Preparation & Storage Diluent: Sterile water Use within: Use immediately after reconstitution Storage: Store lyophilized vials at 2-8 degrees Celsius (36-46 degrees Fahrenheit), protected from light.
contraindication · pending
Baseline humoral immunity HBV DNA and HBeAg When: 3 months (hepatitis B indication) Why: Assess virological response; seroconversion may be delayed 💡 Key Considerations → No preservative in reconstituted solution - use immediately → Contraindication: Avoid in patients on immunosuppressive therapy for organ transplantation; caution in autoimmune diseases where immune stimulation could exacerbate condition Subscribe to unlock this content Get weekly peptide research summaries, new study alerts, and protocol updates — free.
outcome · pending
Restore access No thanks, continue reading Related Reading Peptide KPV anti-inflammatory tripeptide Peptide BPC-157 body protection compound Peptide Glutathione peptide How Thymosin Alpha-1 works at the cellular level Overview of Thymosin Alpha-1 benefits and applications Scientific Details Molecular Formula C129H215N33O55 Molecular Weight 3108.3 Da CAS Number 62304-98-7 Sequence 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 What is Thymosin Alpha-1?
dosing · pending
Patients received TACE with or without concurrent Ta1 1.6 mg SC daily for 5 days per TACE cycle followed by twice-weekly maintenance.
outcome · pending
A meta-analysis of 6 trials including over 500 patients reported that Ta1 combined with TACE was associated with improved 1-year and 2-year overall survival compared to TACE alone.
regulatory · pending
Thymosin Alpha-1 is marketed under the trade name Zadaxin (thymalfasin) and has received regulatory approval in over 35 countries, primarily in Asia, South America, and parts of Europe, for the treatment of chronic hepatitis B virus (HBV) infection, chronic hepatitis C virus (HCV) infection, and as an immune adjuvant.
dosing · pending
It is administered as a subcutaneous injection, typically at doses of 1.6 mg twice weekly.
regulatory · pending
Notably, Ta1 has not received FDA approval in the United States, although it has been granted orphan drug designation for certain indications.
regulatory · pending
Unlike many synthetic peptides that remain in preclinical investigation, Ta1 has an extensive clinical track record spanning several decades, with over 4,400 patients studied in controlled clinical trials and widespread clinical use in approved markets.
mechanism · pending
Mechanism of Action # Thymosin Alpha-1 exerts its immunomodulatory effects through multiple convergent pathways that collectively enhance both innate and adaptive immune responses.
mechanism · pending
Its mechanism centers on the activation of dendritic cells, the promotion of T-cell maturation, and the modulation of cytokine networks.
mechanism · pending
Toll-Like Receptor Signaling # A primary mechanism of Ta1 involves activation of Toll-like receptors (TLRs), particularly TLR9 and TLR2, on dendritic cells and other innate immune cells.
mechanism · pending
TLR9 recognizes unmethylated CpG dinucleotides typically found in microbial DNA, and Ta1 acts as an endogenous ligand or co-stimulatory signal for this receptor.
mechanism · pending
Engagement of TLR9 by Ta1 activates the MyD88-dependent signaling cascade, leading to NF-kB translocation and subsequent upregulation of pro-inflammatory cytokines including interleukin-12 (IL-12), interferon-alpha (IFN-alpha), and tumor necrosis factor-alpha (TNF-alpha).
mechanism · pending
Through TLR2 signaling, Ta1 activates both the MyD88-dependent and TRIF-dependent pathways, promoting dendritic cell maturation and enhanced antigen presentation.
mechanism · pending
cells (pDCs), Ta1 upregulates the expression of co-stimulatory molecules CD80, CD86, and MHC class II, enhancing their capacity to present antigens to T cells.
mechanism · pending
T-Cell Maturation and Differentiation # Ta1 promotes the maturation of immature thymocytes into functional T cells by upregulating the expression of T-cell markers including CD3, CD4, CD8, and the T-cell receptor (TCR) complex.
outcome · pending
Beyond thymic effects, Ta1 augments peripheral T-cell function by increasing IL-2 receptor expression, enhancing IL-2 production by activated T cells, and promoting T-cell proliferation in response to antigenic stimulation.
monitoring · pending
It also supports the expansion of natural killer (NK) cells and enhances NK cell cytotoxicity, contributing to innate immune surveillance.
mechanism · pending
Cytokine Modulation # A notable feature of Ta1 is its context-dependent cytokine modulation.
outcome · pending
The combination also showed reduced recurrence rates and improved quality of life scores.
regulatory · pending
Conversely, in hyperinflammatory conditions, it has demonstrated capacity to reduce excessive pro-inflammatory signaling and promote regulatory T-cell (Treg) activity, suggesting a homeostatic rather than purely stimulatory effect on immune function.
safety · pending
This bidirectional modulation may underlie its favorable safety profile, with minimal risk of cytokine storm or autoimmune activation reported in clinical use.
mechanism · pending
Intracellular Signaling # At the intracellular level, Ta1 activates p38 MAPK and IRF-7 transcription factor pathways in dendritic cells, promoting the transcription of type I interferon genes.
outcome · pending
It also modulates the PI3K/Akt pathway in certain immune cell populations, which may contribute to enhanced cell survival and reduced apoptosis of immune effector cells.
mechanism · pending
Additional evidence suggests that Ta1 can upregulate the expression of indoleamine 2,3-dioxygenase (IDO) in dendritic cells, a mechanism linked to immune tolerance and protection against autoimmune tissue damage.
regulatory · pending
Therapeutic Applications and Clinical Evidence # Chronic Hepatitis B # The most well-established clinical application of Ta1 is in the treatment of chronic hepatitis B virus infection, for which it holds regulatory approval in multiple countries.
dosing · pending
In randomized controlled trials, Ta1 monotherapy (1.6 mg subcutaneous twice weekly for 6 months) demonstrated sustained virological re
outcome · pending
The sustained response, defined as HBV DNA suppression and HBeAg seroconversion, continued to improve beyond the end of treatment, a distinctive feature attributed to the immune-mediated rather than direct antiviral mechanism.
outcome · pending
When combined with interferon-alpha, Ta1 showed enhanced efficacy over interferon monotherapy, with sustained response rates reaching 40-50% in combination arms versus 20-25% for interferon alone.
dosing · pending
Importantly, Ta1 therapy in hepatitis B has demonstrated a favorable safety profile essentially equivalent to placebo, with no dose-limiting toxicities and no flu-like symptoms characteristic of interferon therapy.
safety · pending
This tolerability advantage is significant given that many patients with chronic hepatitis B are unable to tolerate interferon-based regimens.
outcome · pending
Studies combining Ta1 with interferon-alpha and ribavirin in treatment-experienced patients (prior non-responders or relapsers) demonstrated improved sustained virological response rates compared to interfe
contraindication · pending
While the advent of direct-acting antiviral agents (DAAs) has transformed hepatitis C treatment, Ta1 remains relevant in clinical settings where DAA access is limited or where patients have contraindications to standard therapies.
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