How many units is 1.6 mg of Thymosin alpha-1?

It depends entirely on how much water you added. In a 5 mg vial reconstituted with 1 mL, the concentration is 5 mg/mL, so 1.6 mg is 0.32 mL, which is 32 units on a U-100 insulin syringe. In the same vial with 0.5 mL of water it is 16 units, and with 1.5 mL it is 48 units.

How much bacteriostatic water for a 5 mg Thymosin alpha-1 vial?

1 mL is the usual choice. It gives 5 mg/mL, which puts the commonly reported range of 0.5 mg to 3.2 mg between roughly 10 and 64 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.

How many doses are in a 5 mg vial?

Divide 5 by your dose. At 1.6 mg that is 3 doses, which at twice weekly is 10 days.

How many units is 1.6 mg of thymosin alpha-1?

In a 5 mg vial with 1 mL of water, 32 units on a U-100 syringe. With 2 mL, 64 units.

Thymosin alpha-1 dosage calculator

Thymosin alpha-1 has a licensed dose, 1.6 mg twice a week, which makes the arithmetic unusually clear. Enter your vial and water to get the mark.

IndependentThis site does not sell peptides and is not owned by a vendor. Every other calculator on page one of Google belongs to a shop.

The maths is openThe formula is written out on this page and the code behind it is a single file with an automated test suite.

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ReviewedDose ranges and half-life figures last checked 3 September 2026.

Dose to units, at the standard setup

Dose	Draw	U-100 units	Doses per vial	Vial lasts
0.8 mg	0.16 mL	16 units	6	21 days
1.6 mg	0.32 mL	32 units	3	10 days
2.4 mg	0.48 mL	48 units	2	7 days
3.2 mg	0.64 mL	64 units	1	4 days

Based on a 5 mg vial reconstituted with 1 mL of bacteriostatic water, which is 5 mg/mL, drawn on a standard U-100 insulin syringe, twice weekly.

About the numbers above

Thymosin alpha-1 is a 28 amino acid peptide originally isolated from the thymus. As thymalfasin (Zadaxin) it is licensed in a number of countries for hepatitis B and as a vaccine adjuvant, at 1.6 mg by subcutaneous injection twice a week. It is not licensed in the United States and research vials are sold outside any licence.

A 5 mg vial with 1 mL of water is 5 mg/mL, so 1.6 mg is 0.32 mL, or 32 units. With 2 mL of water it is 64 units. Five milligrams is about three licensed doses, so a vial lasts a week and a half at the licensed frequency.

A 5 mg vial at different water volumes

If the draw feels awkward to read, change the water rather than the dose. The dose stays the same; only the mark moves.

Vial	BAC water	Concentration	Draw	U-100 units	Doses/vial
5 mg	1 mL	5 mg/mL	0.32 mL	32 units	3
5 mg	2 mL	2.5 mg/mL	0.64 mL	64 units	3
5 mg	3 mL	1.67 mg/mL	0.96 mL	96 units	3
10 mg	1 mL	10 mg/mL	0.16 mL	16 units	6
10 mg	2 mL	5 mg/mL	0.32 mL	32 units	6
10 mg	3 mL	3.33 mg/mL	0.48 mL	48 units	6

All rows above assume a 1.6 mg dose and a standard U-100 insulin syringe, where 100 units = 1 mL.

How long it stays in you

The half-life of Thymosin alpha-1 is about 2 hours. That is the time for the amount in your blood to halve, so after one half-life you are at 50 percent of the peak, after two you are at 25 percent, and after four you are at roughly 6 percent. This is why it is dosed daily or more often: by the next morning almost none of the previous dose is left, and there is no build-up from day to day.

Common questions

How many units is 1.6 mg of Thymosin alpha-1?: It depends entirely on how much water you added. In a 5 mg vial reconstituted with 1 mL, the concentration is 5 mg/mL, so 1.6 mg is 0.32 mL, which is 32 units on a U-100 insulin syringe. In the same vial with 0.5 mL of water it is 16 units, and with 1.5 mL it is 48 units.
How much bacteriostatic water for a 5 mg Thymosin alpha-1 vial?: 1 mL is the usual choice. It gives 5 mg/mL, which puts the commonly reported range of 0.5 mg to 3.2 mg between roughly 10 and 64 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.
How many doses are in a 5 mg vial?: Divide 5 by your dose. At 1.6 mg that is 3 doses, which at twice weekly is 10 days.
How many units is 1.6 mg of thymosin alpha-1?: In a 5 mg vial with 1 mL of water, 32 units on a U-100 syringe. With 2 mL, 64 units.

Buying Thymosin alpha-1? The where to buy page lists the vendors this site uses and what to check before ordering, and Peptide Bureau keeps the ranked vendor scorecard.

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Read this before you use the numbers. This is a unit-conversion tool. It converts a vial strength and a volume of bacteriostatic water into a concentration, a draw volume and a mark on an insulin syringe. It does not tell you what to take, whether to take it, or whether a compound is safe for you. Most of the compounds listed here are sold for laboratory research use and are not approved for human use. Nothing on this site is medical advice. Dosing decisions belong with a licensed clinician who knows your history. Always confirm the strength printed on your own vial rather than trusting a preset.