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Reconstitution · Semaglutide

Semaglutide reconstitution calculator

Pick the vial, the water you added and the dose. Get the exact draw in units for the syringe in your hand.

Step 1 of 4

  1. How many mg are in your vial?
    Vial amounttotal mg in the calculation
  2. How many mL of water did you add?
  3. What dose do you want to convert?
  4. Which syringe are you using?
Draw to
10.0units

0.10 mL in the syringe · 20 calculated doses from this amount

10.0 units on a U-100 insulin syringe · 1 mL · lines every 2 units, which is 0.10 milliliters. The draw lands on a syringe line.

Easy to read on this syringe. The calculated volume matches the 10-unit line. No rounding is needed.

5 mg ÷ 2 mL = 2.50 mg/mL
→ 25 mcg/unit · 0.25 mg = 0.100 mL = 10.0 units

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Show the math and syringe details

Can this syringe show the result clearly?

Easy to read on this syringe. 10.0 u is exactly the 10-unit line on a U-100 — no rounding error at all.

Want an easier syringe number?

This setup is already easy to read. Changing the water between 0.5 and 3 mL would not put 0.25 mg closer to a line on this U-100 syringe.

Adding more water makes the mixture less concentrated, so the same dose uses more syringe units. It does not change how much peptide is in the vial.

This setup is in the address bar — every input is part of the link.

Educational math, not medical advice — dosing decisions belong to a licensed clinician. The available tabs also show supply calculations and any sourced schedule.

How to use the calculator

  1. 1

    Enter the amount in the vial

    Use the total mg printed on your Semaglutide vial.

  2. 2

    Enter the water you added

    Use the amount of water added to that vial, in mL.

  3. 3

    Enter the dose you want to convert

    Choose mg or mcg, then match the result to your syringe.

Semaglutide is the drug in Wegovy, Ozempic and Rybelsus. It copies a gut hormone called GLP-1, which helps control appetite and blood sugar. People take Wegovy for long-term weight management, and Ozempic or Rybelsus for type 2 diabetes.

All three products have FDA approval. Wegovy and Ozempic are weekly injections; Rybelsus is a daily tablet, and each has its own schedule.

Examples using 5 mg of Semaglutide

Each row uses 5 mg and the liquid volume shown. Dividing the amount by that volume gives the calculated concentration. The rows are arithmetic examples, not alternative product preparations.

◆ How liquid volume changes the resultdose used: 0.25 mg

With 1 mL bacteriostatic water

5.0 units

Concentration
5.00 mg/mL
Each U-100 unit
50.0 mcg
Syringe volume
0.050 mL
Nearest line
6 units · 20.0% off

With 2 mL bacteriostatic water

10.0 units

Starting example
Concentration
2.50 mg/mL
Each U-100 unit
25.0 mcg
Syringe volume
0.100 mL
Nearest line
Exactly 10 units

The amount, liquid volume and dose shown here are the calculator’s starting example for Semaglutide. Replace them with your own values. Every result in the table is calculated from those inputs.

Drawn from once a week at 0.25 mg, a 5 mg vial yields 20 doses — about 20.0 weeks of supply. No storage limit is assigned to this example. Follow the dispensing label for the specific product.

Semaglutide: small draws need the full concentration

A small semaglutide amount in a concentrated liquid may occupy only a few syringe units. The dose, vial amount and liquid volume all matter. A unit count on its own leaves out the information needed to interpret that draw.

Open the mixing details3 notes

Keep tablets, pens and vial calculations separate

Semaglutide has oral and injected forms. Entering a tablet amount here cannot turn it into an equivalent injection. The calculator converts an entered amount into liquid volume; it does not convert one product or route into another.

Pen instructions also belong to the particular device. A syringe unit count for a separate vial is not a pen setting. The product name, dosage form and strength need to stay with the amount when comparing instructions or reading a saved calculation.

Why a small volume can fall between syringe lines

At a fixed semaglutide dose, increasing the concentration reduces the volume needed. The result may fall between the syringe markings even though the calculator can display it to several decimal places. Numerical precision does not create another line on the barrel.

For the same vial amount and dose, the larger water example gives a larger draw. That describes the arithmetic, not a recommendation to add water. Check the result against the selected syringe scale; a setup copied from elsewhere may use a different concentration.

Supply count and storage time are separate

Dividing the amount in a vial by the entered dose estimates how many complete doses it contains. It does not show how long the liquid remains usable. A treatment step lasting several weeks does not establish a storage window for the vial.

The size or appearance of the powder cannot supply that missing information either. Keep preparation and storage instructions separate from the dose-count result. If the prescribed amount changes, the remaining supply calculation changes even when the liquid concentration stays the same.

Semaglutide tablets and injections use different schedules

Semaglutide is available in oral and injected forms. A tablet amount cannot be turned into an equivalent injection by entering it in this calculator. The medicine’s name alone is not enough to identify its dose schedule.

Read the supporting evidence3 supporting notes

Check the form as well as the brand

Wegovy’s label includes both tablets and injections. They have separate starting, step-up and maintenance instructions. A weekly injection schedule does not apply to the daily tablet, even when the brand name matches.

Syringe units depend on the liquid strength

The same amount of semaglutide can occupy different volumes in liquids of different strengths. A unit marking from another vial is not enough to reproduce the dose. The tool needs both the amount wanted and the concentration of the liquid.

The example does not select a maintenance dose

The published injection schedule starts low and increases over time. Which maintenance dose applies depends on the product, the reason for treatment and its prescribing instructions. Changing the calculator’s entry does not change those instructions.

Units to dose at 2.50 mg/mL

Mix 5 mg into 2 mL and one U-100 unit carries 25.0 mcg. The table shows how much peptide is in each numbered syringe line. These are conversion examples, not suggested doses.

Open the unit conversion table10 rows
Numbered U-100 syringe lines converted to volume and mass at 2.50 milligrams per milliliter.
U-100 lineVolumeMass (mcg)Mass (mg)
10 u0.10 mL250 mcg0.25 mg
20 u0.20 mL500 mcg0.5 mg
30 u0.30 mL750 mcg0.75 mg
40 u0.40 mL1,000 mcg1 mg
50 u0.50 mL1,250 mcg1.25 mg
60 u0.60 mL1,500 mcg1.5 mg
70 u0.70 mL1,750 mcg1.75 mg
80 u0.80 mL2,000 mcg2 mg
90 u0.90 mL2,250 mcg2.25 mg
100 u1.00 mL2,500 mcg2.5 mg

Where repeated Semaglutide doses settle

Each weekly dose lands before the last one has cleared. So the level in the body climbs for a while, then holds steady. The half-life here is 7 days, which leaves 50% of a dose still there a week later. The level settles at about 2.00× what one dose gives. It gets 95% of the way there after 5 doses, roughly 4 weeks in.

Open the weekly build-up table9 rows
For each dose: the estimated level just after it and just before the next dose, compared with the first dose, plus how close the peak is to the long-term level.
DoseLevel afterLevel before the nextShare of long-term level
11.00×0.50×50%
21.50×0.75×75%
31.75×0.87×87%
41.88×0.94×94%
51.94×0.97×97%
61.97×0.98×98%
71.98×0.99×99%
81.99×1.00×100%
Plateau2.00×1.00×100%

Half-life Wegovy (semaglutide) — FDA-approved Prescribing Information (DailyMed) · retrieved 2026-08-20. Every other figure is arithmetic on that half-life and the interval.

These are ratios, not blood levels. Turning them into an actual concentration would need more information than the cited source provides. The simple model is also only an approximation of how a drug really behaves in a body. The Accumulation tab plots the same math at whatever interval you pick.

How the math works

  1. Concentration — divide the amount entered by the liquid volume used in the calculation: mg ÷ mL = mg/mL. This tells you how many mg are in each mL.
  2. Volume — the dose divided by that concentration: dose ÷ (mg/mL) = mL.
  3. Units — on a U-100 syringe one unit is 0.01 mL, so mL × 100 = units. A U-40 unit is 0.025 mL, so the wrong barrel is a 2.5× error. That is why the calculator asks which one you have.
  4. Rounding gap — the exact draw against the nearest syringe line: |exact − nearest line| ÷ exact × 100 = % difference.

Medically reviewed by Kenneth Montecillo, MD2026-09-07open the primary sources

Useful guides for this calculation

The math is only one part of the question. These guides cover the compound, published doses, side effects, mixing steps and supplies.

The FDA dates that ended compounded semaglutide

Compounding semaglutide under 503A ended 2025-04-24, under 503B 2025-05-22.

Semaglutide dosage chart with the source for every row

The strongest dose source for semaglutide is an approved label.

The molecule behind Wegovy, Ozempic and Rybelsus

Published half-life: 7 days.

From semaglutide milligrams to syringe lines

Change the water and every semaglutide row moves together, which is what the table is for.

The label instructions behind injecting semaglutide

A guide exists for semaglutide only because an approved label’s instructions do.

Tirzepatide vs semaglutide, from the semaglutide side

SURMOUNT-5 studied 751 adults for 72 weeks. This sits beyond semaglutide.

Questions readers ask

How do you calculate reconstitution?

Divide the vial’s milligrams by the milliliters of water, then read one U-100 unit as a hundredth of a milliliter of the result. A 5 mg vial in 2 mL is 2.5 mg/mL, so each unit carries 25 micrograms.

Semaglutide is where that last step earns its keep. The labeled starting quantity is 0.25 mg, which comes to 10 units at 25 micrograms per unit. Mix 10 mg into 1 mL instead and the same dose is 2.5 units, where one mark ruins the draw.

How do I reconstitute 20 mg of semaglutide?

The preset vials are 2, 5 and 10 mg. For a 20 mg vial, the same formula gives 10 mg/mL with 2 mL of water or 5 mg/mL with 4 mL.

At 10 mg/mL the 0.25 mg starting quantity draws 2.5 units, the weakest reading anywhere in this page’s range. A 20 mg vial also holds 80 of those starting doses. Both facts point one way: a bigger vial wants more water.

How much BAC water for 10 mg of semaglutide?

Either 1 mL or 2 mL, and the choice doubles or halves how far up the barrel the first dose sits. 1 mL is 10 mg/mL and puts 0.25 mg at 2.5 units; 2 mL is 5 mg/mL and puts it at 5.

Neither is a large number, which is this compound’s particular problem. Its whole first month sits at the bottom of the barrel, and the labeled schedule holds each step for four weeks. This page’s sourced window for a mixed vial is 28 days, so one step and one mixed vial tend to end together.

How to reconstitute a 10mg bottle of semaglutide?

You measure the water with a syringe too, and on a U-100 barrel 1 mL is one full draw while 2 mL is two. Most mixing guides skip that step entirely.

After that the vial holds 10 mg in whatever went in, and the pen you may have used before measures nothing for you here. The labeled doses run from 0.25 mg up to 2.4 mg. A 10 mg vial covers 40 starting doses, or 4 at the full maintenance quantity.

1primary source, each with the day we read it — open the documents used on this page