How many units is 0.25 mg of Semaglutide?

It depends entirely on how much water you added. In a 5 mg vial reconstituted with 2 mL, the concentration is 2.5 mg/mL, so 0.25 mg is 0.1 mL, which is 10 units on a U-100 insulin syringe. In the same vial with 1 mL of water it is 5 units, and with 3 mL it is 15 units.

How much bacteriostatic water for a 5 mg Semaglutide vial?

2 mL is the usual choice. It gives 2.5 mg/mL, which puts the commonly reported range of 0.1 mg to 2.4 mg between roughly 4 and 96 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 0.25 mg that is 20 doses, which at once weekly is 140 days.

Why are my units different from someone else's?

Because they used a different amount of water. Units are only meaningful alongside the vial strength and the water volume. Always state all three.

Semaglutide dosage calculator

In a 5 mg vial with 2 mL of water (2.5 mg/mL), 0.25 mg of Semaglutide is 10 units on a U-100 insulin syringe. Semaglutide doses are small, so the draw is small and the water volume matters more than with any other compound here.

Reviewed 3 September 2026
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Dose to units at the usual vial and water

Dose	U-100 units	Draw	Doses per vial	Vial lasts
0.25 mg	10 units	0.1 mL	20	140 days
0.5 mg	20 units	0.2 mL	10	70 days
1 mg	40 units	0.4 mL	5	35 days
1.7 mg	68 units	0.68 mL	2	14 days
2.4 mg	96 units	0.96 mL	2	14 days

5 mg vial in 2 mL of bacteriostatic water (2.5 mg/mL), U-100 insulin syringe, once weekly.

About Semaglutide

Semaglutide is a GLP-1 receptor agonist. The licensed ladder is 0.25, 0.5, 1.0, 1.7 and 2.4 mg once weekly, stepping every four weeks, with 0.25 mg as a starting dose rather than a maintenance one.

Because 0.25 mg is a very small quantity, a 5 mg vial reconstituted with 2 mL puts that dose at 10 units. Reconstituting the same vial with only 1 mL halves it to 5 units, where a small misread is a large proportional error. This is the one compound where erring towards more water is usually the easier choice.

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	0.05 mL	5 units	20
5 mg	2 mL	2.5 mg/mL	0.1 mL	10 units	20
5 mg	3 mL	1.67 mg/mL	0.15 mL	15 units	20
10 mg	1 mL	10 mg/mL	0.025 mL	2.5 units	40
10 mg	2 mL	5 mg/mL	0.05 mL	5 units	40
10 mg	3 mL	3.33 mg/mL	0.075 mL	7.5 units	40

All rows above assume a 0.25 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 Semaglutide is about 6.9 days. 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 a weekly compound still has meaningful levels present when the next dose lands, and why levels build over the first several weeks before they settle.

Common questions

How many units is 0.25 mg of Semaglutide?: It depends entirely on how much water you added. In a 5 mg vial reconstituted with 2 mL, the concentration is 2.5 mg/mL, so 0.25 mg is 0.1 mL, which is 10 units on a U-100 insulin syringe. In the same vial with 1 mL of water it is 5 units, and with 3 mL it is 15 units.
How much bacteriostatic water for a 5 mg Semaglutide vial?: 2 mL is the usual choice. It gives 2.5 mg/mL, which puts the commonly reported range of 0.1 mg to 2.4 mg between roughly 4 and 96 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 0.25 mg that is 20 doses, which at once weekly is 140 days.
Why are my units different from someone else's?: Because they used a different amount of water. Units are only meaningful alongside the vial strength and the water volume. Always state all three.

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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.

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ReviewedDose ranges and half-lives checked 3 September 2026.

Buying Semaglutide?

Peptulator does not list, rank or link vendors. Whoever the supplier is, use the strength printed on your own vial and check the batch certificate of analysis before you rely on any number here.

The Semaglutide guideDosing, evidence and side effects, at Peptide Bureau Read a syringeU-100 vs U-40, and the 2.5x error Build a full protocolThe stack builder at Peptide Bureau, about two minutes

Common conversions

The same three-step maths, pre-filled for the doses people ask about most. Units on a U-100 insulin syringe, where 100 units is 1 mL.

mg to units calculator Any dose at any concentration, both directions, with the full reference tables
Units to mg calculator What the units you drew are in milligrams
1 mg to units The most-asked conversion, at every common setup

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Every one of the 27 compound calculators, charts and tools: the full list.

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.