Semaglutide Dosage Calculator: Working Out Concentration for Research
This page works through, with real numbers, how to convert a vial of semaglutide into a solution of known concentration and read the measured amount on an insulin syringe. It is a reconstitution and concentration worksheet for the research bench, not a guide to human use. The reconstitution calculator does the same arithmetic instantly for any vial and volume.
The relationship behind every reconstitution
Concentration is mass divided by volume. The mass of semaglutide in the vial is fixed and printed on the label; the volume of bacteriostatic water you add is the only variable that sets how concentrated the finished solution is. More solvent gives a more dilute solution, less solvent a more concentrated one.
A worked example, step by step
Take a 5 mg vial of semaglutide. Convert the label to micrograms first: 5 mg is 5,000 mcg. Add 1 mL of bacteriostatic water and the concentration is 5,000 mcg divided by 1 mL, which is 5,000 mcg per mL, or 5 mg/mL. Add 2 mL instead and the same 5,000 mcg is spread across 2 mL, giving 2,500 mcg/mL. The vial holds the same peptide either way; only the concentration changes.
From concentration to units on the syringe
An insulin syringe is graduated in units, with 100 units to a full 1 mL. At 5,000 mcg/mL a full millilitre (100 units) holds 5,000 mcg, so one unit holds 50 mcg. To measure an example 500 mcg aliquot you divide 500 by 50 and draw to 10 units; a 250 mcg aliquot is 5 units. If you instead reconstituted to 2,500 mcg/mL, one unit holds 25 mcg, so 500 mcg becomes 20 units. The concentration is always what converts a line on the barrel into a quantity of peptide.
Reference chart for a 5 mg vial
For a 5 mg semaglutide vial, the chart shows how the solvent volume sets the concentration and how many units correspond to a few example aliquot sizes. Read across from the volume you added.
| Bac. water added | Concentration | 250 mcg | 500 mcg | 1 mg (1000 mcg) |
|---|---|---|---|---|
| 1 mL | 5,000 mcg/mL | 5 units | 10 units | 20 units |
| 2 mL | 2,500 mcg/mL | 10 units | 20 units | 40 units |
| 3 mL | 1,667 mcg/mL | 15 units | 30 units | 60 units |
| 4 mL | 1,250 mcg/mL | 20 units | 40 units | 80 units |
The aliquot sizes in the columns simply demonstrate the arithmetic; substitute whatever amount your own protocol calls for and divide by the per-unit figure.
Choosing a solvent volume
Because the vial always contains 5,000 mcg, reconstituting with 1 mL produces a solution four times more concentrated than 4 mL, and the units per aliquot scale to match. A more dilute preparation is easier to read on the barrel but needs a larger fill volume; a more concentrated one needs tiny draws. Picking a volume that lands your usual aliquot on a round number of units keeps measurement simple, and recording the exact volume makes the result reproducible.
Let the calculator handle any vial
The reconstitution calculator runs all of this for any vial size and any solvent volume and reports micrograms per unit directly. For the physical steps, see the GLP-1 reconstitution guide, and for the formulas the reconstitution math guide.
Storage and verification
Keep the reconstituted vial refrigerated and out of light, and prepare it near the time it is needed. Every figure depends on the material being what the label says, so confirm identity and purity on the COA page before relying on a batch.
Research use only. This article is educational and is not medical, legal, or financial advice. The compounds discussed are not approved for human or veterinary use, consumption, or therapeutic application.