Thymosin Alpha-1
A 28-amino-acid immunomodulatory peptide derived from the thymus. Unlike most peptides on this site it has substantial clinical use: as the licensed drug thymalfasin (Zadaxin) it is approved in several countries for chronic hepatitis B and C and as a vaccine adjuvant, and has been studied in sepsis and cancer. Grey-market 'immune-boosting' use for general wellness is far less well supported than these specific indications.
01 Overview
Thymosin Alpha-1 (Tα1) is a peptide originally isolated from thymic tissue that modulates T-cell function and innate immunity. Marketed as thymalfasin (Zadaxin), it is approved in more than 30 countries (though not the US) for chronic hepatitis B and C and as an immune adjuvant, and has been trialled in sepsis, immunosuppression and as an adjunct in some cancers — giving it a genuine, if mixed, clinical evidence base.
The caveat for consumers: the evidence supports specific medical indications under supervision, not the broad 'boost your immune system' or longevity marketing seen in the peptide scene. Trial results in sepsis and cancer have been mixed, and self-administered wellness use lacks controlled support. It is generally well tolerated, with injection-site reactions the main reported issue.
02 Mechanism
Modulates the immune system by promoting maturation and function of T-cells, enhancing dendritic-cell and natural-killer-cell activity, and modulating cytokine production and Toll-like-receptor signalling, shifting responses toward effective pathogen clearance.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal immune use | 1.5–4.5 mg/wk | SubQ | Wellness/immune dosing varies widely by convention; not a validated indication. |
| Approved (hepatitis) | 1.6 mg | SubQ | Thymalfasin 1.6 mg subcutaneously twice weekly is a standard licensed regimen for chronic hepatitis. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Enhanced T-cell / immune functionImproves T-cell responses and is used clinically as an immune adjuvant. | Clinical | ||
| Antiviral benefit in chronic hepatitisLicensed for chronic hepatitis B and C in many countries, often combined with other antivirals. | Clinical | ||
| Adjunct benefit in sepsis / immunosuppressionStudied as an immune adjunct in sepsis and cancer with inconsistent outcomes. | Mixed trial results | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Injection-site reactionsLocal redness, discomfort or transient erythema at the injection site. | Mild | Common | Clinical | |
| Theoretical autoimmune stimulationAs an immune stimulant there is a theoretical concern about aggravating autoimmune conditions; not clearly established in trials. | Moderate | Rare/theoretical | Unconfirmed |