GHRP-2 5 mg vial
How much bacteriostatic water to add to a 5 mg vial of GHRP-2, 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 GHRP-2 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 2× per day, it lasts about 3.6 weeks.
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 | |||
|---|---|---|---|---|
| 1 mL | 2 mL | 2.5 mL | 3 mL | |
| 100 mcg | ||||
| 150 mcg | ||||
| 200 mcg | ||||
| 250 mcg | ||||
| 300 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 only: one 100 mcg IV dose after an overnight fast (children aged 4–17: 2 mcg/kg, up to 100 mcg). Not a treatment regimen.
- Trial Nasal spray, 50–200 mcg (by body weight) twice daily for 48 weeks in children with GH deficiency; no growth benefit over placebo.
- Community 100 mcg per injection (often framed as about 1 mcg/kg), 1–3× daily on an empty stomach; some guides go up to 200–300 mcg.
Doses are what labels, trials or community reports reference, not recommendations. GHRP-2’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: Powder: frozen or refrigerated. Mixed: 2–8 °C, use within about 3–4 weeks.
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 GHRP-2?
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 GHRP-2?
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 GHRP-2?
About 50 doses of 100 mcg, or 20 of 250 mcg or 16 of 300 mcg. Taken 2× per day at 100 mcg, it lasts about 3.6 weeks.
How long does a mixed vial of GHRP-2 keep?
Powder: frozen or refrigerated. Mixed: 2–8 °C, use within about 3–4 weeks.
Other vial sizes
Sources
- GHRP Kaken 100 (pralmorelin hydrochloride) package insert, Japan, rev. July 2025
- Chihara et al., GHRP-2 test for adult GH deficiency (Eur J Endocrinol 2007) PMID 17609397
- Tanaka et al., GHRP-2 nasal spray in children with GH deficiency (Clin Pediatr Endocrinol 2014) PMID 25374440
- FDA: bulk drug substances for compounding that may present significant safety risks (GHRP-2), April 2026
The math on this page uses the doses and storage on GHRP-2’s page.