GHRP-6 vs GHRP-2: two secretagogues, two very different half-lives

What are GHRP-6 and GHRP-2, and what does the comparison ask?

GHRP-6 is a hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, with a molecular weight of 872.44 Da, described as a growth hormone secretagogue [1]. GHRP-2, also called pralmorelin, is a synthetic hexapeptide that specifically stimulates growth hormone release in people [3][4]. Neither is growth hormone itself; that is somatropin, a 191 amino acid protein covered in the HGH explainer.

PinPoint's library lists both as limited human research, logged by subcutaneous injection [4]. The questions behind the search are which one acts longer, which has been studied in people, and how a vial converts. The first two have numbers in published papers; the third depends on a package amount.

What do the GHRP-6 and GHRP-2 human studies report?

The GHRP-6 study, published in 2013, gave nine healthy men a single intravenous bolus at 100, 200 or 400 mcg/kg and measured the peptide by mass spectrometry [1]. Its disposition fitted a two-phase model, with a distribution half-life of 7.6 minutes and an elimination half-life of 2.5 hours, and exposure rose roughly in proportion to the amount. Four of the nine showed unexplained concentration spikes during elimination.

For GHRP-2, a 1998 study gave ten prepubertal children with short stature a single 1 mcg/kg intravenous dose and reported a terminal half-life of 0.55 hours, with growth hormone peaking about 25 minutes later [2]. A second 1998 study gave nine healthy young men 100 mcg by subcutaneous injection once daily for five days [3]. Peak growth hormone fell from 83 on day 1 to 51 mcg/l on day 5, and mean IGF-I did not rise.

So the GHRP-6 half-life comes from adult men and the GHRP-2 half-life from children, both after intravenous dosing. The library carries those values, 2.5 and 0.55 hours, into a subcutaneous tracking model and labels the absorption side as an extrapolation [4].

How do GHRP-6 and GHRP-2 vials convert to syringe units?

Neither GHRP-6 nor GHRP-2 has a verified package behind its library entry: the GHRP-6 guide and the GHRP-2 guide both record that the supplier amount stored for each could not be re-verified, so this page gives no vial example for either [4]. A concentration needs the actual labeled amount and the final volume of liquid; with those two numbers from a real label, the peptide calculator divides the labeled amount by the final volume to calculate concentration [5]. Separately, a draw volume in millilitres times 100 gives U-100 units [5].

What the sources do allow is a comparison of time. At 2.5 hours, a single modeled GHRP-6 contribution halves twice by 5 hours; at 0.55 hours, GHRP-2 halves twice in 66 minutes [5]. These are model halvings from intravenous studies, as the figure lists, not measured subcutaneous levels.

How do people log GHRP-6 and GHRP-2 in PinPoint?

Each is its own entry in PinPoint, logged with compound, dose, site and pain level [6][4]. Vial setup takes a size in mg or mcg with a water volume and shows concentration and syringe units, with a fill-line guide for 0.3, 0.5 and 1.0 mL insulin syringes [6].

Daily or custom schedules carry reminders at the times set, and site rotation suggests where to inject next [6]. The Home curve draws GHRP-6 from its 2.5 hour input and GHRP-2 from its 0.55 hour input, so the two curves fall at very different speeds; they are mathematical visualizations that do not account for individual variation [4][6].

What do people ask about GHRP-6 and GHRP-2?

What is the difference between GHRP-6 and GHRP-2?

Both are synthetic hexapeptides that release growth hormone. In their human intravenous studies, GHRP-6 had a 2.5 hour elimination half-life in adult men and GHRP-2 a 0.55 hour half-life in children.

What is the half-life of GHRP-6?

The 2013 study in nine healthy men reported a distribution half-life of 7.6 minutes and an elimination half-life of 2.5 hours after an intravenous bolus.

Does GHRP-2 keep working with daily use?

In a five-day study of nine young men given daily subcutaneous injections, the growth hormone response weakened from day 1 to day 5 and IGF-I did not rise.

Is there a verified GHRP-6 or GHRP-2 vial size?

No. The package amounts stored for both come from supplier pages that could not be re-verified, so no vial example is given. A concentration needs the labeled amount and final volume from an actual label.

Where do these facts come from?

Sources are listed by kind: labels first, then peer-reviewed papers, then PinPoint's own library, arithmetic and app description. Library values were retrieved from the PinPoint application on 5 October 2026; vendor listings support package sizes only.

1. Pharmacokinetic study of GHRP-6 in nine healthy male volunteers, 2013European Journal of Pharmaceutical Sciences, 2013. Single intravenous bolus at 100, 200 and 400 mcg/kg; distribution half-life 7.6 minutes, elimination half-life 2.5 hours.Retrieved 2026-10-05 · study
2. Pharmacokinetics and pharmacodynamics of GHRP-2, phase I study in children, 1998Journal of Clinical Endocrinology and Metabolism, 1998. Ten prepubertal children; single 1 mcg/kg intravenous dose; terminal half-life 0.55 hours.Retrieved 2026-10-05 · study
3. Five days of subcutaneous GHRP-2 in healthy young men, 1998European Journal of Endocrinology, 1998. Nine men, 100 mcg daily by subcutaneous injection for 5 days; growth hormone response attenuated and IGF-I did not rise.Retrieved 2026-10-05 · study
4. PinPoint compound library, application recordsHalf-life inputs, routes, frequencies, package examples and confidence labels as stored in the iOS app library and mirrored in the peptide guides.Retrieved 2026-10-05 · library
5. Unit conversion arithmeticConcentration = amount / volume; volume = amount / concentration; U-100 units = mL x 100; remaining fraction = 2^(-elapsed / half-life).Retrieved 2026-10-05 · arithmetic
6. PinPoint App Store descriptionFeature wording from the approved application description, not pricing.Retrieved 2026-10-05 · app-description