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

Semaglutide doses are small, so the draw is small and the water volume matters more than with any other compound here.

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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
0.25 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.

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.

Buying Semaglutide?

The where to buy page lists the vendors this site uses and what to check first. Peptide Bureau keeps the ranked scorecard.

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

All calculators and charts

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Tirzepatide calculator The 2.5 to 15 mg ladder, converted
Semaglutide calculator (this page)
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Growth hormone axis

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CJC-1295 (no DAC) calculator No-DAC and DAC, mcg to units
CJC-1295 / Ipamorelin blend calculator The 5 mg + 5 mg blend, per component
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Hexarelin calculator mcg doses to units
IGF-1 LR3 calculator Tens of mcg from very small vials
AOD-9604 calculator 300 mcg daily, in units
MOTS-c calculator 5 to 10 mg, two or three times a week

Repair, skin and blends

BPC-157 calculator mcg doses from a 5 or 10 mg vial
TB-500 calculator Loading and maintenance, in units
BPC-157 / TB-500 blend calculator The Wolverine stack, per component
GHK-Cu calculator 50 to 200 mg vials, mg doses
GLOW blend calculator The 70 mg blend, split per component
KLOW blend calculator The 80 mg blend, split per component

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Glutathione calculator Hundreds of mg, or a 200 mg/mL solution

Dosage charts and schedules

Peptide reconstitution chart Concentration for every vial and water combination
Peptide dosing chart Printable unit tables for every compound
Retatrutide titration schedule 2 to 12 mg in units, stage by stage
Tirzepatide titration schedule 2.5 to 15 mg in units, stage by stage
Semaglutide titration schedule 0.25 to 2.4 mg in units, stage by stage
KLOW dosage and frequency chart The 80 mg blend at 2, 3 and 4 mL, both phases
GLOW dosage chart The 70 mg blend, units to each peptide
Wolverine stack dosing chart BPC-157 + TB-500, blend and separate vials
MOTS-c dosage chart 5 and 10 mg vials at three water volumes
Tirzepatide reconstitution chart Every vial size, every water volume, the whole ladder
Retatrutide dosing chart 1 to 12 mg across 10, 20 and 30 mg vials
Printable dosing charts Four one-page charts to save, pin or print

Tools

Peptide calculator The general tool, any compound
Reconstitution calculator How much water to add, and why it matters
mg to units calculator Both directions, any concentration
Bacteriostatic water calculator Pick a volume that lands where you can read it
How to read an insulin syringe U-100 vs U-40, and the 2.5x error
The Protocol Pack Free 25-page printable reference
Where to buy Vendor notes and what to check first
1 mg to units on an insulin syringe The conversion table for every common concentration

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.