Dose calculator

GHRP-2 dose calculator

Convert any GHRP-2 dose into syringe units in real time, pre-filled with a 5 mg / 2 mL example.

Download Peptide PilotiPhone · Free to download

Draw on a U-100 syringe

0.00 units

Volume to draw

0.000 mL

GHRP-2 is a short-acting injectable peptide people use to trigger sharp pulses of their own growth hormone, usually paired with a GHRH like CJC-1295 or sermorelin. It mimics ghrelin at the GH-secretagogue receptor, producing a strong but brief GH spike within minutes of injection. Published studies show clear post-injection GH peaks, with some appetite increase as a side effect. This page covers reconstitution math and per-injection logging cadence.

How the GHRP-2 dose calculator works

This calculator answers a simple question: given the concentration of the GHRP-2 solution already in your vial, how many syringe units does today's dose work out to? It is the second half of the reconstitution math — the first half locks in concentration, this one converts any dose mg or mcg into a clean unit count.

The formula is volume in mL equals dose mg divided by concentration mg/mL, then volume times one hundred to get units on a U-100 insulin syringe. With a 2.5 mg/mL GHRP-2 solution and a 0.1 mg dose, the draw is 0.04 mL or about 4 units. Type any other dose and the unit count updates in real time — no spreadsheets, no guesswork.

Inputs that genuinely matter: concentration (which only changes when you reconstitute a new vial) and dose mass. Syringe type matters too, but only because U-100 vs U-40 changes the multiplier — almost every modern insulin syringe is U-100, which is why the math defaults to that. Edge cases worth flagging: switching from mcg to mg without checking the input unit, or carrying yesterday's unit count over to a new vial that was reconstituted with a different volume of BAC water.

Most people use this calculator at two moments: when titrating a dose up or down, and when prepping a single dose before injection. The output is meant to be checked against the syringe before drawing — read the markings, confirm the unit count, then draw. The calculator is fast precisely so you can do that check every time without it feeling like a chore.

How GHRP-2 dosing is tracked

Published research on GHRP-2 frequently documents protocols that involve multiple administrations throughout the day, typically ranging from one to three separate doses. This dosing cadence is a direct consequence of the peptide's short half-life, a common characteristic among all synthetic ghrelin agonists that necessitates repeated stimulus to study sustained effects. A standard U-100 insulin syringe is almost universally employed for this purpose, as it provides the necessary precision to accurately measure and draw the small liquid volumes corresponding to typical dose magnitudes of around 100 micrograms.

The timing of administration is a critical variable studied in these protocols, with doses often scheduled on an empty stomach, such as upon waking or several hours after a meal. This timing is planned to prevent the potential blunting effect that circulating glucose and fatty acids can have on the pulsatile release of growth hormone. For anyone documenting a personal protocol, this makes time-stamping each log entry essential. Without this data point, a log of a three-times-daily schedule rapidly degrades into a simple tally that cannot be used to analyze patterns or correlate observed outcomes to a specific morning, mid-day, or evening administration.

A second consideration documented in the comparative literature is how a multi-dose schedule interacts with cumulative weekly exposure. Three 100 mcg doses per day for seven days produce 2,100 mcg of weekly exposure from a single 5 mg vial, which means a vial reconstituted at the example concentration of 2,500 mcg/mL lasts roughly two and a half weeks at that cadence — a useful number to know in advance when planning reorders, since running out mid-cycle disrupts whatever pattern the log was attempting to capture. Researchers who document this kind of long-running protocol typically also note ambient temperature during transport between dose times, because a vial carried in a warm bag for several hours each day is not in the same storage condition as one that lives continuously in a refrigerator, and the difference is worth recording even if the visible appearance of the solution does not change.

GHRP-2 mechanism in plain English

GHRP-2 functions as an agonist of the growth hormone secretagogue receptor, type 1a (GHSR-1a), the same receptor targeted by the endogenous hormone ghrelin. Although it shares this primary mechanism with its predecessor, GHRP-6, its modified hexapeptide structure alters its binding characteristics and subsequent intracellular signaling. The substitution of a D-Alanine residue is a key factor in this functional difference. This distinction in receptor interaction is what underlies the observed differences noted in comparative literature, where GHRP-2 often produces a strong GH pulse with a reduced propensity for stimulating the intense hunger response sometimes associated with GHRP-6. The compound's action is entirely mediated through the ghrelin receptor pathway, a separate mechanism from that of GHRH and its analogs.

Common GHRP-2 dose mistakes

  • Mistaking GHRP-2 for GHRP-6 and failing to account for the documented differences in their side-effect profiles regarding appetite stimulation and prolactin.
  • Neglecting to log the specific time of day for each dose in a multi-dose schedule, which renders later analysis of the data almost meaningless.
  • Using a large-volume syringe (e.g., a 3 mL syringe) that lacks the fine gradations needed to accurately measure a typical 100 mcg dose volume.
  • Administering a dose immediately following a large meal, a variable noted in research that can interfere with the peptide's primary action.
  • Basing dose calculations on a previous vial's concentration without verifying the milligram amount and diluent volume for the new vial.

Frequently asked questions about GHRP-2 dose

How is GHRP-2 structurally different from GHRP-6?
GHRP-2 is a synthetic hexapeptide with the sequence D-Ala-D-2-Nal-D-Trp-D-Phe-Lys-NH2. It was developed as a second-generation evolution of GHRP-6. The primary structural difference is the substitution of the natural L-Alanine found in GHRP-6 with a synthetic D-Alanine residue. This single amino acid change significantly alters the molecule’s interaction with the ghrelin receptor, giving rise to its different selectivity profile.
Why do studies describe GHRP-2 as more selective than GHRP-6?
In comparative scientific studies, GHRP-2 has been observed to stimulate a potent release of growth hormone while having a lesser impact on cortisol, prolactin, and appetite compared to dose-equivalent administrations of GHRP-6. This means its action is more focused on GH release. While it targets the same ghrelin receptor, its modified structure results in this more specific downstream effect, though it is still considered less selective than the third-generation peptide ipamorelin.
If a 5 mg vial of GHRP-2 is reconstituted with 2 mL of water, how many units are drawn for a 100 mcg dose?
When a 5 mg (5,000 mcg) vial is reconstituted with 2 mL of diluent, the final concentration becomes 2,500 mcg per mL. To calculate the volume for a 100 mcg dose, you divide the dose by the concentration: 100 mcg ÷ 2,500 mcg/mL equals 0.04 mL. On a U-100 insulin syringe, 0.04 mL corresponds to exactly 4 units.
What is the rationale for the multiple daily administrations sometimes seen in research logs?
Like other peptides in the ghrelin mimetic class, GHRP-2 has a very short biological half-life, meaning its action dissipates quickly after administration. To study the effect of more sustained GH elevation, research protocols often involve scheduling multiple smaller doses throughout the day. This approach contrasts with using a single, larger dose, which would produce a more acute but less frequent pulse.
Why is it so important to log the time of day when documenting a GHRP-2 protocol?
Because study protocols can involve one, two, or three administrations per day, a log entry that only states the date and dose amount is incomplete. A timestamp clarifies if it was a morning dose on an empty stomach, a pre-workout dose, or a pre-bedtime dose. This granular detail is crucial for any meaningful retrospective analysis, as the timing of administration relative to other factors like meals is a key variable.
Does GHRP-2 work through the same mechanism as a GHRH analog like Sermorelin?
No, they operate via completely separate and distinct pathways. GHRP-2 is a ghrelin receptor agonist, mimicking the hormone ghrelin to stimulate the pituitary gland through the GHSR-1a receptor. In contrast, GHRH analogs like Sermorelin work by binding to the Growth Hormone-Releasing Hormone receptor (GHRHR). While both pathways ultimately lead to GH release, they are independent mechanisms.

Related on Peptide Pilot

Log every GHRP-2 dose in the app

Download on the App Store