How the Thymosin Alpha-1 calculator works
Lyophilized (freeze-dried) powder in a sealed vial, labelled in milligrams. The quick-fill buttons in the calculator are the vial sizes Thymosin Alpha-1 is commonly labelled in (1.6 mg, 5 mg and 10 mg). If yours is different, type it in.
Amounts of Thymosin Alpha-1 are usually written in milligrams (mg), so the calculator opens in mg.
If your vial is the licensed product, use the diluent and the volume given in its own instructions rather than any figure from this page.
For a field-by-field walkthrough and a guide to syringe types, see the main peptide calculator.
Thymosin Alpha-1 concentration table
Each labelled vial size at the same three round water volumes used across this site. It shows how the arithmetic behaves and is not a suggestion of what to use.
| Vial | Water added | Concentration | Each mark holds |
|---|---|---|---|
| 1.6 mg vial | 1 mL | 1.6 mg/mL | 0.16 mg per 10 units |
| 1.6 mg vial | 2 mL | 0.8 mg/mL | 0.08 mg per 10 units |
| 1.6 mg vial | 3 mL | 0.53 mg/mL | 0.053 mg per 10 units |
| 5 mg vial | 1 mL | 5 mg/mL | 0.5 mg per 10 units |
| 5 mg vial | 2 mL | 2.5 mg/mL | 0.25 mg per 10 units |
| 5 mg vial | 3 mL | 1.67 mg/mL | 0.167 mg per 10 units |
| 10 mg vial | 1 mL | 10 mg/mL | 1 mg per 10 units |
| 10 mg vial | 2 mL | 5 mg/mL | 0.5 mg per 10 units |
| 10 mg vial | 3 mL | 3.33 mg/mL | 0.333 mg per 10 units |
Every row for a given vial holds the same total. To compare volumes for a specific reading, use the BAC water calculator.
The formula, step by step
The “Try example numbers” button uses one fixed rule on every page: the smallest labelled vial, 2 mL of water, and whatever amount lands on the 10-unit mark. The amount is a by-product of that rule and not a typical or suggested Thymosin Alpha-1 dose.
- Concentration: 1.6 mg ÷ 2 mL = 0.8 mg/mL.
- The 10-unit mark is 10 ÷ 100 = 0.1 mL, which holds 0.1 × 0.8 = 0.08 mg.
- Run it forwards to check: 0.08 mg ÷ 0.8 mg/mL = 0.1 mL, and 0.1 × 100 = 10 units.
Thymosin Alpha-1: general reference
General educational reference for research purposes only. None of it is a recommendation, none of it is medical advice, and none of it is used by the calculator, which works only on the numbers you enter.
Thymosin alpha-1 is a peptide of 28 amino acids that was first isolated from thymus tissue. The synthetic version is called thymalfasin.
Thymalfasin is sold as Zadaxin and is approved as a prescription medicine in more than 35 countries, including China and Italy. It has never been approved by the FDA.
The licensed product is a 1.6 mg vial of freeze-dried powder that comes with its own diluent and its own instructions.
- Class
- 28-amino-acid thymic peptide
- Group
- Thymosins and BPC-157
- Also known as
- Thymalfasin, Zadaxin
- Molecular weight
- About 3,108 Da
- Half-life
- About 2 hours. Published reviews give a half-life in the circulation of about 2 hours.
- Regulatory status
- Approved in more than 35 countries, not by the FDA. Thymalfasin is an approved prescription medicine in more than 35 countries. It has never been approved by the FDA, and its position in US pharmacy compounding has changed since 2023, so check the FDA’s current lists for the present status.
- Labelled vial sizes
- 1.6 mg, 5 mg and 10 mg
Arithmetic slips to watch for with Thymosin Alpha-1
The licensed vial is 1.6 mg
That is an unusual size, and the arithmetic follows it: 1.6 mg in 1 mL is 1.6 mg/mL, so 10 units on a U-100 syringe holds 0.16 mg. Research vials of 5 mg and 10 mg give very different concentrations with the same volume.
Not the same thing as TB-500
Thymosin alpha-1 and thymosin beta-4 (the parent of TB-500) share a name because both were first found in thymus extracts. They are unrelated molecules of different sizes. A number worked out for one tells you nothing about the other.
Watch the decimal point
1.6 and 16 differ by ten times. Amounts are written in milligrams with decimals, and the “Show the math” panel prints every step so a slipped decimal is easy to see.
What this page does not do
The calculator performs mathematical conversions only. It does not recommend, suggest or verify any Thymosin Alpha-1 dose or schedule, it does not say how much water to add, and it does not say what Thymosin Alpha-1 is for, whether it is safe, or whether it is legal where you live. It is not medical advice, diagnosis or treatment, and Peptrack does not sell, supply or endorse any substance.
Always confirm measurements with a licensed healthcare provider or pharmacist. See the full disclaimer.
Zadaxin is a trademark of its owner. Peptrack is not affiliated with, or endorsed by, any manufacturer.
Sources
- Dominari et al. (2020), Thymosin alpha 1: a comprehensive review of the literature, World Journal of Virology
- FDA: bulk drug substances used in compounding under section 503A
Facts last checked: September 2026. Regulatory status changes, so check the regulator’s own pages for the current position.
