Thymosin Alpha-1 (Tα1), also known as thymalfasin, is a synthetic 28-amino-acid peptide studied for its immunomodulatory effects. The amount of liquid added to a vial determines the resulting concentration; there is therefore no single universal BAC-water volume for every Thymosin Alpha-1 research vial.
There is no scientifically universal BAC-water volume that applies to every Thymosin Alpha-1 vial. The correct mathematical relationship is determined by the total amount of peptide in the vial and the volume of diluent selected for the desired research concentration.
| Vial Quantity | 1 mL | 2 mL | 2.5 mL | 3 mL | 5 mL |
|---|---|---|---|---|---|
| 1.6 mg | 1.6 mg/mL | 0.8 mg/mL | 0.64 mg/mL | 0.533 mg/mL | 0.32 mg/mL |
| 5 mg* | 5 mg/mL | 2.5 mg/mL | 2 mg/mL | 1.667 mg/mL | 1 mg/mL |
| 10 mg* | 10 mg/mL | 5 mg/mL | 4 mg/mL | 3.333 mg/mL | 2 mg/mL |
*The 5 mg and 10 mg rows are mathematical examples for a vial containing that verified quantity. They are not presented here as standardized or FDA-approved Thymosin Alpha-1 vial sizes. Always verify the actual quantity stated on the vial, certificate of analysis, or applicable product documentation.
Use the BacScience calculator to calculate concentration from a custom vial quantity and liquid volume.
A documented pharmaceutical presentation of thymalfasin contains 1.6 mg per vial. A current Singapore National Drug Formulary entry specifies 1 mL of sterile water for injection for that particular product, producing a nominal mathematical concentration of 1.6 mg/mL.
That product-specific instruction should not be generalized to every Thymosin Alpha-1 research vial or replaced with a blanket BAC-water recommendation.
Mathematical concentration: 1.6 mg/mL
If a research vial is independently verified to contain 5 mg of Thymosin Alpha-1, the concentration depends entirely on the liquid volume selected. For example, 5 mg divided by 2 mL equals 2.5 mg/mL, while 5 mg divided by 5 mL equals 1 mg/mL.
If the verified vial contains 10 mg, the same concentration formula applies. For example, 10 mg in 2 mL produces 5 mg/mL, while 10 mg in 3 mL produces approximately 3.33 mg/mL.
Thymosin Alpha-1 (Tα1) is a synthetic peptide corresponding to a naturally occurring thymic peptide. The pharmaceutical form thymalfasin is an acetylated 28-amino-acid peptide with a molecular weight of approximately 3.1 kDa.
Research has focused on its ability to influence immune signaling, including aspects of innate and adaptive immune function.
The mechanism of Tα1 is complex and is not adequately described by the phrase "immune booster." Published research describes effects involving immune-cell differentiation, dendritic-cell signaling, Toll-like receptor pathways and cytokine regulation.
Human and preclinical research has investigated Tα1 in a range of immune-related settings. Published work includes research involving chronic hepatitis B, hepatitis C, severe infections, sepsis, immune dysfunction and oncology-related applications.
The strength of evidence differs substantially between indications. A research finding should therefore not be interpreted as proof that Tα1 is effective for every condition in which it has been investigated.
Thymosin Alpha-1 has a substantial clinical research history, including randomized and controlled studies. However, clinical evidence varies by indication, population, comparator and study design.
| Study | Population | Dose Studied | Route | Frequency | Duration | Key Finding |
|---|---|---|---|---|---|---|
| Japanese randomized chronic hepatitis B trial | 316 adults with chronic hepatitis B | 0.8 mg or 1.6 mg | Subcutaneous | Protocol-dependent | 24 weeks | Long-term virologic and biochemical outcomes were evaluated; both dose groups showed clinical responses. |
| HBV-related acute-on-chronic liver failure RCT | 120 enrolled patients | 1.6 mg | Subcutaneous | Daily during week 1, then twice weekly | 12 weeks | The study reported improved 90-day liver-transplantation-free survival in the treatment group, although competing-risk analysis did not show a significant survival difference. |
| Pilot chronic hepatitis B study | 16 patients | 0.8 mg or 1.6 mg | Subcutaneous | Six times weekly initially, then twice weekly | 24 weeks | Investigated dose-related treatment response and HBV markers. |
Doses and schedules in this table are historical or contemporary published research parameters. They are not BacScience treatment instructions.
Human studies have investigated different Tα1 quantities and schedules. Examples include 0.8 mg and 1.6 mg regimens in chronic hepatitis B research and a 1.6 mg regimen in a study of HBV-related acute-on-chronic liver failure.
Investigated in a randomized chronic hepatitis B study.
Published research quantityA commonly reported quantity in historical clinical research.
Published research quantityMathematical concentration for 1.6 mg in 1 mL.
1.6 mg ÷ 1 mLPreclinical studies have examined how Tα1 influences immune cells, signaling pathways and responses to infection, inflammation and cancer models.
Animal models have investigated Tα1 in infectious disease, immune dysfunction and oncology-related settings. These studies can provide mechanistic and hypothesis-generating information, but animal findings cannot establish human efficacy or safety.
Reconstitution calculations are fundamentally volume-and-mass calculations. The vial's total peptide quantity remains the numerator; the selected liquid volume is the denominator.
Increasing the volume of liquid while keeping the vial's total peptide quantity constant produces a lower mg/mL concentration.
Decreasing the volume while keeping the same peptide quantity produces a higher mg/mL concentration.
Enter the verified vial quantity and selected liquid volume in the BacScience calculator.
Adding a different volume of diluent does not change the total amount of peptide represented by the vial. It changes the concentration of the resulting solution.
| Vial | Liquid Volume | Calculation | Resulting Concentration |
|---|---|---|---|
| 1.6 mg | 1 mL | 1.6 ÷ 1 | 1.6 mg/mL |
| 1.6 mg | 2 mL | 1.6 ÷ 2 | 0.8 mg/mL |
| 1.6 mg | 3 mL | 1.6 ÷ 3 | 0.533 mg/mL |
| 1.6 mg | 5 mL | 1.6 ÷ 5 | 0.32 mg/mL |
FDA records show thymalfasin orphan-drug designations for several conditions, but those designations do not constitute FDA approval. FDA's current orphan-drug records identify thymalfasin as not FDA approved for those orphan indications.
FDA has also evaluated Thymosin Alpha-1-related substances in the context of bulk drug compounding. FDA materials describe concerns involving potential immunogenicity, peptide aggregation, peptide-related impurities and difficulties in characterization.
Regulatory status is jurisdiction-specific. For example, the Singapore National Drug Formulary currently lists Zadaxin injection containing 1.6 mg of Thymosin Alpha-1 per vial and identifies chronic hepatitis B among its indications.
An international approval should not be interpreted as evidence that the same product or indication is FDA-approved in the United States.
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There is no universal volume for every Thymosin Alpha-1 vial. The volume determines the resulting concentration. Use the verified vial quantity and calculate concentration as mg divided by mL.
A documented pharmaceutical 1.6 mg/vial thymalfasin product is supplied with product-specific reconstitution instructions using 1 mL sterile water for injection. This should not be generalized to every research formulation or substituted automatically with bacteriostatic water.
1.6 mg divided by 1 mL equals 1.6 mg/mL.
1.6 mg divided by 2 mL equals 0.8 mg/mL.
Divide the total peptide quantity in milligrams by the liquid volume in milliliters: Concentration = mg ÷ mL.
No. Assuming no material loss, adding more liquid changes the concentration, not the total quantity of peptide originally present in the vial.
No. FDA orphan-drug records identify thymalfasin designations but state that it is not FDA-approved for those orphan indications.
Regulatory status varies by country. For example, Singapore's National Drug Formulary currently lists Zadaxin containing 1.6 mg of Thymosin Alpha-1 per vial.
Published human research has included quantities such as 0.8 mg and 1.6 mg in chronic hepatitis B research, with other studies using 1.6 mg under different protocols. Published research doses should not be interpreted as individualized treatment recommendations.
No. A research dose describes what investigators administered within a specific study design. It does not automatically become a recommendation for another population, indication or product.
Yes. The calculator is designed to perform the mathematical relationship between a verified vial quantity and a selected liquid volume.
The page should use primary or high-quality scientific sources rather than vendor pages, forums or community protocols for clinical and regulatory claims.
September 10, 2026
Scientific content basis: FDA regulatory materials, PubMed-indexed literature and official international product information.
Reviewer: BacScience Scientific Content Team