Skip to content
Peptigraph home

Oxytocin reconstitution calculator

Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated Educational use only
1Vial size
2Bacteriostatic water added
3Dose per injection
4Syringe (U-100)
Draw to
10units
= 0.1 mL on a 1 mL U-100 insulin syringe
2 mg vial2 mL water100 mcg dose
Concentration
1 mg/mL
Doses per vial
20
Weeks (1 dose/wk)
20
Math only. It does not recommend a dose. Oxytocin: FDA approved (prescription only).

10 units (0.1 mL) on a 1 mL U-100 syringe: 100 mcg from a 2 mg vial + 2 mL water (Oxytocin).

Dosing table for a 2 mg vial

Syringe units (U-100) for each dose, by how much bacteriostatic water you add.

Oxytocin: U-100 syringe units per dose for a 2 mg vial
Dose1 mL water2 mL water2.5 mL water3 mL water
10 mcg0.511.251.5
25 mcg1.252.53.133.75
50 mcg2.556.257.5
100 mcg51012.515
200 mcg10202530
500 mcg255062.575

How the math works

Concentration is the vial's milligrams divided by the water you add. Volume to draw is your dose divided by that concentration. On a U-100 syringe, 1 mL is 100 units, so units = mL × 100.

2 mg ÷ 2 mL = 1 mg/mL
100 mcg = 0.1 mg; 0.1 mg ÷ 1 mg/mL = 0.1 mL
0.1 mL × 100 = 10 units

How many units is 100 mcg of Oxytocin?

With a 2 mg vial and 2 mL of bacteriostatic water, 100 mcg is 10 units (0.10 mL) on a U-100 syringe. With 1 mL of water it is 5 units. The answer always depends on how much water was added.

How much bacteriostatic water for a 2 mg Oxytocin vial?

The water only sets the concentration; the amount of Oxytocin in the vial stays the same. 2 mL makes 1 mg/mL, so 100 mcg is 10 units. 2.5 mL makes 0.8 mg/mL, so the same 100 mcg is 12.5 units. More water makes small doses easier to measure but needs more volume per injection.

How many 100 mcg doses are in a 2 mg vial?

2 mg is 2,000 mcg; 2,000 ÷ 100 = 20, so 20 full doses of 100 mcg. Any liquid lost in the needle and vial is not counted.

Preset doses are round numbers for the arithmetic, not dosing guidance. Vial sizes are the ones most often mentioned for Oxytocin in community discussions.

10 units · 0.1 mL · 100 mcg from 2 mg + 2 mL

Sources

  1. 1Metric (SI) Prefixes (NIST Reference on Constants, Units, and Uncertainty)National Institute of Standards and Technology (NIST) · 2025physics.nist.govAccessed 2 Oct 2026
  2. 2BASAGLAR (insulin glargine) injection, prescribing information (DailyMed)U.S. Food and Drug Administration / DailyMed (Eli Lilly and Company label) · 2026dailymed.nlm.nih.govAccessed 2 Oct 2026

Found an error? Report a correction.