In plain English
Thymosin Alpha-1 is a 28-amino-acid peptide made by the thymus, the gland that trains your immune cells. It helps the immune system respond better to infections while keeping inflammation in balance. Under the name Zadaxin, it has been prescribed in more than 30 countries for decades.
What it's used for
- Immune support during infections or periods of stress
- Chronic viral infections such as hepatitis B and C (its main medical use outside the US)
- Boosting vaccine response
- Immune support with age
Benefits
In human studies, Thymosin Alpha-1 has been shown to:
- Improve immune response in chronic hepatitis B and C
- Boost response to vaccines, especially in older or immune-weakened people
- Support T-cell function and immune balance
- Have a very good safety record across decades of medical use
Users report getting sick less often and recovering faster from colds and infections.
How it works
In simple terms: Thymosin Alpha-1 helps your immune system’s “special forces,” the T cells, mature and work properly.
It acts on immune cells through toll-like receptors, helping dendritic cells and T cells recognize and respond to threats. It boosts helpful immune activity while also helping to calm excessive inflammation, which is why it is described as an immune balancer rather than simply a booster.
Development history
- 1970s: Isolated from thymus tissue by Allan Goldstein and colleagues.
- 1990s onward: Approved as Zadaxin (thymalfasin) in more than 30 countries, including China and Italy, for hepatitis B and C and as an immune enhancer.
- 2020: Studied in hospitals for severe viral infections.
- Today: Widely used for immune support.
Typical protocols
The standard medical dose used where Zadaxin is prescribed is shown below; users of research vials report similar or shorter courses.
| Use | Dose | Frequency | Length |
|---|---|---|---|
| Zadaxin standard dose | 1.6 mg | Twice weekly | 6–12 months for hepatitis |
| Short immune course (users report) | 1.5 mg | Twice weekly, or daily for 1–2 weeks during illness | 2–8 weeks |
Cycling
Commonly used in courses of a few weeks to a few months, or short bursts during illness.
Administration options
Subcutaneous injection, usually in the belly or upper arm.
Reconstitution and dosing calculator
Thymosin Alpha-1 commonly comes in 5 mg or 10 mg vials and is mixed with 1–2 mL of bacteriostatic water.
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This tool does arithmetic only. It does not choose a dose or confirm that any substance is right for you. Double-check every result against your syringe and your clinician’s instructions.
Side effects and safety
- Thymosin Alpha-1 has an excellent safety record in medical use. Occasional effects include injection-site redness or discomfort.
- People with autoimmune conditions or organ transplants, who take immune-suppressing medicines, should be cautious about anything that stimulates the immune system.
- Avoid during pregnancy and breastfeeding.
Common stacks
- BPC-157: combined by users for gut and immune support.
- Thymalin and Epitalon: combined in Russian-style longevity courses.
- LL-37: combined by some users during infections.
Storage
Powder: refrigerate, dry and away from light.
After mixing: refrigerate at 2–8 °C and use within about 4 weeks.
Compare with
- Thymalin: a mix of thymus peptides used in Russia.
- TB-500 (thymosin beta-4 fragment): shares the "thymosin" name but is a repair peptide, not an immune peptide.
Frequently asked questions
Is Thymosin Alpha-1 related to TB-500?
Only by name. Both were found in thymus tissue, but Thymosin Alpha-1 works on the immune system while TB-500 works on tissue repair.
When do people use it?
Users commonly take it during cold and flu season, during illness, or for general immune support with age.
Is it safe?
It has a long safety record from medical use in many countries, with injection-site reactions the most common side effect.
References
- Goldstein AL, Goldstein AL. From lab to bedside: emerging clinical applications of thymosin alpha 1. Expert Opin Biol Ther. 2009;9(5):593-608.
- Romani L, et al. Thymosin alpha 1: an endogenous regulator of inflammation, immunity, and tolerance. Ann N Y Acad Sci. 2007;1112:326-338.