Gonadorelin 5 mg vial

How much bacteriostatic water to add to a 5 mg vial of Gonadorelin, the syringe units for each common dose, and how many doses the vial holds.

Water: 2.5 mL
Strength: 2 mg/mL
Common dose: 100 mcg
Draw: 5 units0.05 mL
Doses per vial: 50

The short answer

Mixed with 2.5 mL of bacteriostatic water, a 5 mg vial of Gonadorelin holds 2 mg/mL. A 100 mcg dose is then 5 units (0.05 mL) on a U-100 insulin syringe, and the vial holds about 50 doses of that size. Taken 3× per week, it lasts about 17 weeks.

Approved drug. A copy of the body’s own GnRH, approved for decades. Both US products are gone: Factrel (1982) and Lutrepulse (1989) are listed as discontinued. Approved products remain in Europe, including the Lutrelef pump for hypothalamic amenorrhea and a 100 mcg diagnostic injection in the UK. Pump therapy has good evidence in fertility; the popular use alongside testosterone therapy has no controlled trial.

Gonadorelin page

How much water

The water only sets the strength; the dose and the number of doses in the vial stay the same. Draws are on a U-100 insulin syringe, where 1 unit is 0.01 mL.

Water added	Strength	Per syringe unit	Draw for 100 mcg
1 mL	5 mg/mL	50 mcg	2 units (0.02 mL)
2 mL	2.5 mg/mL	25 mcg	4 units (0.04 mL)
2.5 mL	2 mg/mL	20 mcg	5 units (0.05 mL)
3 mL	1.667 mg/mL	16.7 mcg	6 units (0.06 mL)

Dose chart

Syringe units for each common dose at each water volume. Select a cell to open it in the calculator.

Dose	Water added
Dose	1 mL	2 mL	2.5 mL	3 mL
50 mcg
60 mcg
75 mcg
100 mcg
150 mcg
200 mcg

Draws over 100 units show in mL. Faded values are under 2 units, which is hard to measure. Check that your vial holds the larger volumes.

Where the doses come from

Label Diagnostic test: a single 100 mcg dose under the skin or into a vein, with LH measured before the dose and at 15, 30, 45, 60 and 120 minutes.
Trial Pulsatile pump: 10 mcg under the skin every 90 minutes, adjusted to keep LH and FSH in range; ovulation-induction practice uses about 5–20 mcg per pulse every 60–120 minutes.
Community 100–200 mcg under the skin, 2–3× weekly alongside testosterone therapy; some guides argue the short half-life makes daily dosing the minimum.

Doses are what labels, trials or community reports reference, not recommendations. Gonadorelin’s page has the cycle, side effects, cautions and sources.

Mixing and storage

PrepareLet a refrigerated vial come to room temperature, and wipe both stoppers with an alcohol swab.
Add 2.5 mLDraw 2.5 mL of bacteriostatic water and let it run slowly down the inside wall of the vial.
Swirl, don’t shakeSwirl gently until the powder dissolves and the liquid is clear.
Label itWrite the date and the strength, 2 mg/mL, on the vial.

Storage: Research vials, mixed: 2–8 °C, use within about 4 weeks. The approved vial is stored below 25 °C and used within 24 hours of mixing.

The reconstitution guide covers each step, and the units page explains syringe markings.

Questions

How much water do I add to a 5 mg vial of gonadorelin?

There’s no single right amount: the water only sets the strength. With 2.5 mL of bacteriostatic water, a 5 mg vial holds 2 mg/mL. With 1 mL it’s 5 mg/mL; with 2 mL it’s 2.5 mg/mL; with 3 mL it’s 1.667 mg/mL. Less liquid makes each dose a smaller draw; more makes small doses easier to measure.

How many units is 100 mcg of gonadorelin?

With 2.5 mL in a 5 mg vial, 100 mcg is 5 units (0.05 mL) on a U-100 insulin syringe. With 1 mL, 2 units (0.02 mL); with 2 mL, 4 units (0.04 mL); with 3 mL, 6 units (0.06 mL).

How many doses are in a 5 mg vial of gonadorelin?

About 50 doses of 100 mcg, or 33 of 150 mcg or 25 of 200 mcg. Taken 3× per week at 100 mcg, it lasts about 17 weeks.

How long does a mixed vial of gonadorelin keep?

Research vials, mixed: 2–8 °C, use within about 4 weeks. The approved vial is stored below 25 °C and used within 24 hours of mixing.

Other vial sizes

Sources

Gonadorelin 100 micrograms powder for solution for injection (HRF), UK summary of product characteristics, revised 7 October 2022
FDA Drugs@FDA records for Factrel (NDA 018123, approved 1982) and Lutrepulse (NDA 019687, approved 1989), both discontinued
Mao et al., pulsatile GnRH versus combined gonadotropin therapy in congenital hypogonadotropic hypogonadism (Asian J Androl 2017) PMID 28051040
Quaas et al., pulsatile GnRH in functional hypothalamic amenorrhea, 25-year cohort (J Assist Reprod Genet 2022) PMID 36378460
FDA, bulk drug substances nominated for use in compounding under section 503B, categories 1 to 3 (updated March 21, 2025)

The math on this page uses the doses and storage on Gonadorelin’s page.

By Vial Guide editorsLast reviewed October 7, 2026

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