Thymosin Alpha-1
Thymosin Alpha-1 (Thymalfasin)
Also called Thymosin alpha-1, Tα1, thymalfasin, Zadaxin
The immune modulator
Thymosin alpha-1 is made by your thymus, the gland that trains your immune cells and shrinks steadily from your teens onward. The drug version is approved in over thirty countries for hepatitis and used as an immune support elsewhere. It nudges the immune system rather than suppressing or stimulating it bluntly.
A 28-amino-acid peptide naturally produced by the thymus gland. Thymosin Alpha-1 is one of the most clinically validated peptides in existence — approved in over 35 countries for hepatitis B/C and as an immune adjuvant. It enhances T-cell maturation, dendritic cell function, and bridges innate and adaptive immunity.
- Typical dose
- 1.6 mg 2x/week
- Availability
- Research-only
Tested in several human trials
What people use Thymosin Alpha-1 for
Reported uses, roughly in order of how often they are the reason someone goes looking. Whether it works for any of them is a separate question, answered under each one.
- Immune support
- The main reason people use it. It helps T-cells mature and improves how the immune system recognises threats, which is why it turns up in people who catch everything or who are recovering from a long illness.
- Hepatitis B and C
- Its approved use in the countries where it is licensed, usually alongside other treatment.
- Ageing immune function
- The thymus shrinks with age and so does your supply of this. That is the argument for replacing it, and it is reasoning rather than proof.
Mechanism of Action
How Thymosin Alpha-1 works
Thymosin Alpha-1 orchestrates immune function through multiple coordinated mechanisms:
- T-cell maturation — promotes differentiation of immature T-cells (thymocytes) into functional CD4+ and CD8+ cells, restoring immune surveillance that declines with thymic involution after age 30
- Dendritic cell activation — stimulates dendritic cell maturation and antigen presentation via TLR9 signaling, improving the immune system's ability to identify and respond to threats
- NK cell enhancement — increases natural killer cell cytotoxicity, the first-line defense against virus-infected and abnormal cells
- Cytokine balancing — modulates IL-2, IFN-alpha, and IFN-gamma production without overstimulating inflammatory cascades, making it immunomodulatory rather than purely immunostimulatory
Thymosin Alpha-1 dosage calculator
Opens at 1.6 mg, from the doses reported for Thymosin Alpha-1. Change any box to match your own vial. It works out where to pull the plunger to.
How much is in the vial?
Printed on the label, in milligrams
How much water did you add?
Bacteriostatic water, in millilitres
What dose are you taking?
The dose you already intend to use
Which syringe?
Barrel size, printed on the wrapper
Draw to
32 units
on a 0.5 mL insulin syringe (0.32 mL)
- Strength once mixed
- 5 mg/mL
- Doses in the vial
- 6
10 mg in 2 mL makes 5 mg/mL. A 1.6 mg dose is 0.32 mL of that, which is 32 units.
Want a rounder number? Adding 0.63 mL instead would put this dose at exactly 10 units, which is easier to draw accurately.
This is arithmetic, not advice. It converts a dose you already have into a mark on a syringe. It does not tell you what dose to take, and Thymosin Alpha-1 is not prescribed by us. Dosing belongs with a qualified clinician.
Thymosin Alpha-1 side effects: what people reported
Unusually well tolerated for something with real clinical use behind it. Most trials report side effects close to placebo.
What people report
- Injection-site redness or discomfort
- Occasional tiredness in the first days
- Mild aching, like the start of a cold
Worth keeping an eye on
- It modulates immune activity, so anyone with an autoimmune condition should be discussing it with a doctor rather than experimenting
- Anyone on immune-suppressing medication after a transplant should not be nudging the immune system in the other direction
Source: Clinical trials in hepatitis plus prescribing experience where it is approved. This is a summary of published findings, not a complete safety profile and not medical advice. Thymosin Alpha-1 should only be considered with a qualified clinician who knows your history.
Your Genetics & Thymosin Alpha-1
The genes involved in how Thymosin Alpha-1 works
Thymosin Alpha-1 works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
HLA-DRB1 · ••
HLA-DRB1 variants determine which antigens your immune system can recognize. Certain alleles are associated with weaker viral clearance — Thymosin Alpha-1's dendritic cell enhancement may compensate for suboptimal antigen presentation.
TNF · ••
The -308G>A promoter polymorphism increases TNF-alpha production. High TNF producers may experience stronger initial immune activation with Thymosin Alpha-1, but its modulatory effect helps prevent overactivation.
Affects IL-2 production, the primary growth factor for T-cells. Low IL-2 producers may see greater benefit from Thymosin Alpha-1's ability to upregulate IL-2 signaling and T-cell expansion.
TLR9 is the receptor through which Thymosin Alpha-1 activates dendritic cells. The -1237T>C variant affects TLR9 expression — carriers of the C allele may have altered dendritic cell response to Thymosin Alpha-1.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which variants do you carry?
Upload your DNA data, or get tested through our partner, to find out.
Commonly combined with
What Thymosin Alpha-1 is most often paired with, and why:
BPC-157
Immune + Gut Recovery StackModerate EvidenceBody Protection Compound 157
BPC-157 is the peptide people reach for when something will not heal. Tendons, ligaments, a gut that has been irritated by painkillers, an injury that has stalled. It is a short chain of amino acids copied from part of a protein your stomach already makes, and the animal research on it is unusually consistent for this category: across a lot of separate rat studies, injured tissue healed faster than it did without it. The gap is that this has largely not been repeated in people, and it is not an approved medicine, so nobody is checking what is in the vial you buy.
3
Gene variants
19+
Studies
KPV
Immune + Anti-Inflammatory StackEmerging EvidenceKPV (Lys-Pro-Val)
A three-amino-acid fragment snipped off the end of a hormone your body already makes. Almost every page describes it as switching on a melanocortin receptor; the research fairly clearly says it does not. What it appears to do instead is more interesting, and it is why nearly all the good data is about the gut rather than skin.
4
Gene variants
15+
Studies
Sourcing & access
Where to buy Thymosin Alpha-1
Thymosin Alpha-1 is sold as a research compound, not a licensed medicine, so quality and legal status vary widely by country and vendor. If you're sourcing it, treat independent purity testing as non-negotiable.
- Insist on a recent third-party Certificate of Analysis (COA) for the exact batch — labs like Janoshik verify purity and identity.
- Check the legal status where you live before ordering — it differs from country to country.
- Reconstitute correctly with bacteriostatic water and start at a conservative dose.
Before you buy: see whether your DNA actually responds to Thymosin Alpha-1, and at what dose. Analyze my DNA — $99 →
Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you). Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Worth knowing before you consider Thymosin Alpha-1
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- Autoimmune conditions are the real caution
- A compound that helps the immune system respond more sharply is not obviously a good idea if your immune system is already attacking you.
- Approved somewhere is not approved everywhere
- It is a licensed medicine in dozens of countries and not in the US, which is why the same compound is a prescription in one place and a research vial in another.
Last updated
Frequently Asked Questions
What is Thymosin Alpha-1 used for?
Thymosin Alpha-1 is used to enhance immune function. It is FDA-approved in over 35 countries (as Zadaxin) for chronic hepatitis B and C, and used as an immune adjuvant in cancer immunotherapy. It restores T-cell function, enhances dendritic cell activity, and is particularly valuable for age-related immune decline.
Does genetics affect Thymosin Alpha-1 response?
Yes. HLA-DRB1 variants affect antigen presentation efficiency, TNF-alpha variants influence baseline inflammatory tone, and IL-2 variants determine T-cell proliferation capacity. Genetic testing identifies whether your immune system has specific gaps that Thymosin Alpha-1 is best positioned to fill.
Is Thymosin Alpha-1 safe?
Thymosin Alpha-1 has one of the strongest safety profiles of any peptide. It has been used in clinical settings for over 30 years with minimal side effects. Its immunomodulatory (not immunostimulatory) nature means it enhances immune function without triggering dangerous overactivation.
Learn more about Thymosin Alpha-1
9 guides mention Thymosin Alpha-1→stacking
In depth7 Thymosin Alpha-1 Stack Mistakes (And Why Thymulin and Cortagen Belong in the Protocol)
13 min read
peptide guides
In depthThymosin Alpha-1 Dosage and Benefits: What 11,000 Human Subjects Actually Showed
13 min read
peptide guides
Thymulin: The Immune Peptide Your Thymus Stops Making at 60 (And What Happens Next)
13 min read
peptide guides
Best Peptides for Healing & Recovery: Ranked by Evidence (2026)
12 min read
safety
Peptide Pharmacy Europe 2026: Why the Magistral Loophole Does Not Work the Way You Think
11 min read
safety
7 Signs Your Peptide Protocol Is Doing More Harm Than Good (And How to Fix Each One)
12 min read
Your next move
Two ways forward with Thymosin Alpha-1.
Not sure it's for you?
How does Thymosin Alpha-1 relate to your genes?
Your report scores Thymosin Alpha-1 against your receptor, pharmacogene and pathway variants and shows the genetic markers relevant to it, with commonly cited dosing information to review with a clinician.
Analyze my DNA — $99Already decided?
Get Thymosin Alpha-1 from Swiss Chems.
A US research-chemical supplier with third-party Certificates of Analysis. Sold for research use only — check your local laws before ordering.
Buy at Swiss Chems →Save 10% at checkout with code tcwisiiu