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Thymosin Alpha-1
Pick your pack · how long it lasts
At 3.20 mg/wk — select pack size
1 × 10-vial pack required for packing — samples add on to any pack
Lab-direct quality — full packs or single-vial samples
Every batch ships straight from the lab that synthesises it — sealed, tamper-evident, and HPLC-verified to >99% purity with a batch-linked Certificate of Analysis. Buying direct means you pay the lab-direct rate on every vial, with nothing stacked on top.
Order a full sealed 10-vial research pack for a complete study supply, or add a single-vial sample alongside your pack to trial a new compound first. Same lab, same batch, same verified purity — scaled to whatever your research needs.
What It's Researched For
In plain terms, Thymosin Alpha-1 is studied as an immune-balancing peptide that helps tune the body's defences up or down. Here is what that looks like across the research.
Immune support
Research explores how it strengthens a worn-down immune system and helps mature the T-cells the body uses to fight infection.
Antiviral defence
In clinical research it is investigated for helping clear viral infections such as hepatitis B, and it is approved as Zadaxin in more than 30 countries.
Calming an overactive response
Clinical studies look at its use in severe infection (sepsis), where the focus is rebalancing an overwhelmed immune system rather than just boosting it.
Natural-killer-cell activity
Studied for sharpening the front-line immune cells that target both viruses and abnormal cells.
Overview
Thymosin Alpha-1 (Zadaxin) is a 28-amino-acid thymic peptide that activates multiple Toll-like receptors to rebalance both innate and adaptive immunity, approved as an immunomodulator in more than 30 countries.
Thymosin Alpha-1 (Tα1) is a small naturally occurring peptide produced from the prohormone prothymosin alpha in thymic tissue. The thymus is where T-cells mature, and Tα1 turns out to be one of the signals that tells immune cells how to differentiate and respond.
What makes Tα1 clinically interesting is its dual effect on the immune system. It activates Toll-like receptors 2, 3, 4, 7, and 9 - the innate-immunity sensors that detect viral and bacterial signatures - while also supporting T-cell maturation, NK cell cytotoxicity, and dendritic cell function on the adaptive side. In conditions where the immune system is either exhausted (like chronic hepatitis B) or overwhelmed (like sepsis), Tα1 acts as a rebalancer rather than a blunt stimulant or suppressant.
Marketed globally as Zadaxin, Thymosin Alpha-1 is approved in over 30 countries and holds FDA orphan drug designation for melanoma, hepatitis B, DiGeorge syndrome, and hepatocellular carcinoma. Supplied here as sterile lyophilised powder for in-vitro and preclinical research.
Mechanism of Action
Thymosin Alpha-1 activates innate immune Toll-like receptors while supporting T-cell maturation, reshaping both arms of the immune system rather than just boosting or suppressing it.
Romani et al. (Molecules, 2023) reviewed the mechanism and showed that Tα1 binds multiple TLRs directly - an unusual multi-receptor innate activity. Li et al. (Critical Care Medicine, 2015) published a meta-analysis of 12 sepsis RCTs (N = 1,480) showing a pooled mortality relative risk of 0.68 (p < 0.00001) versus placebo. In chronic hepatitis B, randomised studies reported 40.6% HBV DNA clearance at 6 months versus 9.4% in controls. Subcutaneous Tmax is ~2 hours, serum t½ ~2 hours, with return to baseline within 24 hours.
Common Questions People Are Asking
What is Thymosin Alpha-1 and how does it work?
Thymosin Alpha-1 is a 28-amino-acid N-terminally acetylated thymic peptide derived from prothymosin alpha. It works by directly engaging multiple Toll-like receptors (TLR2/3/4/7/9) on innate immune cells, triggering IRF3, NF-κB, p38MAPK and MyD88 signalling, while also supporting maturation of CD4+/CD8+ T-cells, NK-cell cytotoxicity, and dendritic-cell antigen presentation. This dual innate-plus-adaptive action is why it is described as an immune rebalancer rather than a simple stimulant.
What does "immunomodulator" mean versus "immunostimulant"?
An immunostimulant broadly revs up immune activity; an immunosuppressant broadly shuts it down. An immunomodulator like Tα1 rebalances — it can amplify weak responses in immune-exhausted states like chronic viral infection, while helping calm overactivation in conditions like sepsis. The same molecule can do both because the immune system regulates itself differently in different states.
What does the clinical research actually show?
The evidence is genuinely mixed. Chronic hepatitis B studies reported higher HBV DNA clearance versus controls, and COVID-19 work suggested restoration of lymphocyte counts and reversal of T-cell exhaustion. But the rigorous multicentre phase-3 TESTS sepsis trial (2025) found no significant 28-day mortality benefit. So while the mechanism is well characterised, the clinical efficacy picture is not uniformly positive — and none of this is human-use guidance.
What dosing appears in the published literature?
Published clinical trials describe a 1.6 mg dose (approximately 900 μg/m² of body surface area) administered subcutaneously twice weekly, the schedule used across most of the sepsis, hepatitis B, and immune-support studies. Subcutaneous Tmax is roughly 2 hours and serum half-life around 2 hours, with return toward baseline within 24 hours. These are descriptive research parameters only; Tα1 is supplied for laboratory research.
How does Thymosin Alpha-1 differ from Thymulin or Thymopoietin?
They are all thymic peptides but completely different molecules with different mechanisms. Tα1 is a 28-residue peptide derived from prothymosin alpha that binds TLRs and supports T-cell maturation. Thymulin is a nonapeptide that requires zinc for activity, and thymopoietin is a 49-residue polypeptide. They are sometimes grouped together as "thymic factors" but act distinctly.
Is Thymosin Alpha-1 approved or legal?
Thymosin Alpha-1 is marketed as Zadaxin and approved as an immunomodulator in more than 30 countries, and it holds FDA orphan-drug designation for several indications — but it is not an FDA-approved drug for general therapeutic use in the United States. New-U supplies it strictly as a research-grade compound for in-vitro and preclinical laboratory research, not for human use; buyers are responsible for local compliance.
How should Thymosin Alpha-1 be stored and reconstituted?
Keep the lyophilised powder frozen at −20 °C. After reconstitution with bacteriostatic water, refrigerate at 1–6 °C and protect from light. Tα1 is reasonably stable in solution within the normal peptide-handling window; avoid repeated freeze-thaw cycles. This is laboratory handling guidance only.
Where can I buy Thymosin Alpha-1?
Right here — Thymosin Alpha-1 is supplied directly by New-U Research Compounds on this page. Every batch is independently third-party tested to >99% HPLC purity with a batch-linked Certificate of Analysis, supplied as lyophilised research-grade material, and shipped direct from source worldwide in discreet, tracked packaging. Strictly for laboratory research use only — not for human use.
How much does Thymosin Alpha-1 cost?
Thymosin Alpha-1 pricing is shown live on this page, per pack size — 10-vial research packs as standard, with single-vial sample options on selected compounds. Larger vial strengths lower the per-mg cost, every order includes the batch Certificate of Analysis, and shipping is free on orders over $300.
Is Thymosin Alpha-1 third-party tested?
Yes. Every Thymosin Alpha-1 batch is verified by independent laboratories (Janoshik Analytics and Freedom Diagnostics) for identity and purity, with a batch-linked Certificate of Analysis confirming >99% purity by HPLC. Every order ships with its COA, and current batch certificates are published on our COA page.
How do I buy Thymosin Alpha-1?
Add the Thymosin Alpha-1 pack size you need to your cart and check out: enter your shipping details, then choose your payment method — cryptocurrency or card — on the next step. Every order ships with its batch Certificate of Analysis (COA). Thymosin Alpha-1 is supplied strictly for laboratory research use only, not for human or veterinary use.
What payment methods can I use to buy Thymosin Alpha-1?
At checkout you can pay by cryptocurrency (BTC, ETH, SOL, LTC, USDC, USDT and more) or by card, each handled by a dedicated secure payment provider. You choose your method after confirming your order.
How fast is shipping, and do you ship worldwide?
Yes — we ship worldwide in discreet, unmarked, temperature-stable, tracked packaging. Delivery typically takes 6–14 business days, and shipping is free on orders over $300.
Pharmacokinetics
Evidence Tier
Overall: Tier 1: Human clinical
Thymosin Alpha-1 has the strongest human clinical dataset in this batch (multiple RCTs, a sepsis meta-analysis and hepatitis B trials) and is an approved immunomodulator in 30+ countries — but the efficacy picture is genuinely mixed, as the rigorous phase-3 TESTS sepsis trial was negative. It is NOT FDA-approved for general therapeutic use; the research-grade material supplied here is unapproved laboratory material in the US.
Tier 1 · Human clinical
Source References & Further Reading
Last reviewed: 16 June 2026 · New-U Research Compounds
Key Characteristics
Specifications
About Thymosin Alpha-1 (Zadaxin / Thymalfasin): Immune Modulator Research Guide
Thymosin Alpha-1 (Tα1, thymalfasin) was first purified from thymic tissue in the 1970s as part of a broader effort to identify the signals the thymus uses to orchestrate T-cell maturation. It turned out that a small 28-residue peptide, derived from the larger prothymosin alpha protein, carries much of that activity. That discovery launched decades of clinical development that ended with Zadaxin approved in more than 30 countries as an immunomodulator.
The clinical dataset is what makes Tα1 stand out among research peptides in the immune category. Earlier meta-analysis across twelve randomised sepsis trials (nearly 1,500 patients) reported a pooled mortality reduction, and Tα1 was studied for reversing T-cell exhaustion in severe COVID-19. More recent high-quality work tempers that picture: the multicentre phase-3 TESTS trial (2025) found no significant 28-day mortality difference versus placebo in sepsis, so the honest research position is mixed rather than settled. HBV DNA clearance data in chronic hepatitis B and FDA orphan-drug designations for melanoma and hepatocellular carcinoma round out an unusually deep but not uniformly positive profile.
New-U Research Compounds supplies Thymosin Alpha-1 as a research-grade lyophilised powder at >99% HPLC purity, verified by independent third-party labs. All material is strictly for in-vitro and preclinical research use. Note the clinical contraindication in organ transplant recipients, where Tα1's immunostimulatory effect is undesirable. Nothing on this page constitutes medical advice.
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