How long does GHRP-2 stay in your system?
GHRP-2 has a published half-life of 0.55 ± 0.14 hours (about 33 minutes). By the standard pharmacology rule of thumb, a drug is about 97% eliminated after roughly five half-lives, which here works out to about 2.75 hours. The figure was measured in prepubertal children rather than adults.
Source: Pihoker et al., J Clin Endocrinol Metab 1998 (PMID 9543135) · Peer-reviewed · measured: intravenous bolus · dataset reviewed September 23, 2026
What is the half-life of GHRP-2?
GHRP-2's published half-life of 0.55 ± 0.14 hours, about 33 minutes, comes from a 1998 study in the Journal of Clinical Endocrinology and Metabolism, measured after an intravenous bolus. GHRP-2, also called pralmorelin, is a synthetic hexapeptide that activates the ghrelin receptor and prompts the pituitary to release growth hormone.
The study population matters more than usual here. The value was measured in 10 prepubertal children with short stature, not in adults. Children and adults can differ in body composition, organ function and hormonal status, so this is a paediatric value and should be stated as one rather than presented as a generic adult figure.
How much GHRP-2 is left after each half-life?
Each half-life removes half of whatever is left, so the percentages are pure arithmetic and the same for any compound; only the clock changes. For GHRP-2, one half-life is 33 minutes. The rows below run that forward for a single amount with nothing added.
| Half-lives elapsed | Time elapsed | Remaining | Cleared |
|---|---|---|---|
| 1 | 33 minutes | 50% | 50% |
| 2 | 66 minutes | 25% | 75% |
| 3 | 1.65 hours | 12.5% | 87.5% |
| 4 | 2.2 hours | 6.25% | 93.75% |
| 5 | 2.75 hours | 3.13% | 96.88% |
| 6 | 3.3 hours | 1.56% | 98.44% |
| 7 | 3.85 hours | 0.78% | 99.22% |
Why do the numbers differ between sources?
Because the only human value we can trace is paediatric, any adult figure you see for GHRP-2 needs its own primary source. We did not find one we were willing to cite. A plausible-looking adult number with no study behind it is not better than an honest paediatric one.
Route matters too. The figure was measured after an intravenous bolus, and subcutaneous absorption can stretch the apparent curve. GHRP-2's only national approval, in Japan, is as a single-dose diagnostic agent for growth hormone deficiency, not as a therapy.
What does a half-life not tell you?
GHRP-2 is cleared in well under an hour, but it does more than release growth hormone. Unlike ipamorelin, it measurably raises ACTH, cortisol and prolactin in human studies, and it stimulates appetite through the ghrelin pathway. Each of those responses follows its own time course.
The growth hormone pulse it produces is also larger when GHRH is present, because the two act through separate, synergistic pathways. A half-life describes only the peptide's own disappearance, never the size or duration of the hormonal response. GHRP-2 is prohibited in sport by WADA.
Can you run the numbers yourself?
The estimator applies the same decay arithmetic to any half-life, starting amount and time you enter. It opens with GHRP-2's published value loaded. Type another figure to see how sensitive the result is to it.
Published value: 0.55 ± 0.14 hours (about 33 minutes) (Intravenous bolus) · Pihoker et al., J Clin Endocrinol Metab 1998 (PMID 9543135) · Compound profile
Show the math
What are the limits of this estimate?
Everything above is a single-compartment approximation: one pool of drug, falling by the same fraction in every interval. Real elimination varies with kidney and liver function, body composition, formulation and route, and a published figure describes only the route and the people it was measured in. Many compounds also show a fast distribution phase before the slower elimination the table describes.
A half-life is not a dosing schedule. Labelled intervals come from clinical trials that measured outcomes and tolerability, and nothing on this page suggests when to take, repeat or stop anything. Whether GHRP-2 is out of your system for drug-testing purposes is a different question again. Tests often look for metabolites rather than the parent compound, and the answer depends on the assay, its sensitivity and the sample type, none of which a plasma half-life captures.
FAQ.
Was GHRP-2's half-life measured in adults?
No. The 0.55 ± 0.14 hour figure was measured in 10 prepubertal children with short stature after an intravenous bolus. We found no adult value we were willing to cite, so this page states the paediatric figure as exactly that.
Is GHRP-2 approved anywhere?
In Japan it is approved, as pralmorelin, only as a single-dose diagnostic agent for assessing growth hormone deficiency, not as a treatment. It is not FDA-approved. The legal status page covers its regulatory position.
Does GHRP-2 clear faster than GHRP-6?
On the published figures, yes: about 33 minutes for GHRP-2 in children against an elimination half-life of 2.5 ± 1.1 hours for GHRP-6 in healthy males. The populations differ, so treat the comparison as indicative rather than exact.
For what the evidence on GHRP-2 actually shows, read the GHRP-2 profile. For approval and regulatory position, see is GHRP-2 legal. The half-life reference lists every sourced value side by side, including the compounds where a number circulates online with no reliable human data behind it.