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.

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25 printable pages: dosing cards for the twelve most-used compounds at three water volumes, titration planners, a vial log, and five pages on what to do when it has already gone wrong.

Dose to units at the usual vial and water

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

5 mg vial in 1 mL of bacteriostatic water (5 mg/mL), U-100 insulin syringe, twice weekly.

About Thymosin alpha-1

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.

The same 5 mg vial at other water volumes

If the draw is awkward to read, change the water, not 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 lasts in the body

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.

IndependentThis site does not sell peptides and is not owned by a vendor.

The maths is openThe formula is on every page and in the methodology. The code is one file with an automated test suite, run before each deploy.

How it earnsAffiliate links on one marked page, never inside the calculator.

ReviewedDose ranges and half-lives checked 3 September 2026.

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Where to buyWhat to check before you order Vendor scorecardRanked vendors, at Peptide Bureau Build a full protocolThe stack builder at Peptide Bureau, about two minutes

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