How long does GHRP-6 stay in your system?
GHRP-6 has a published half-life of 2.5 ± 1.1 hours (elimination); 7.6 ± 1.9 minutes (distribution). By the standard pharmacology rule of thumb, a drug is about 97% eliminated after roughly five half-lives, which here works out to about 12.5 hours. That uses the elimination phase; the faster distribution phase governs only the first minutes after an intravenous bolus.
Source: Cabrales et al., Eur J Pharm Sci 2013 (PMID 23099431) · Peer-reviewed · measured: intravenous bolus · dataset reviewed September 23, 2026
What is the half-life of GHRP-6?
GHRP-6 has a published elimination half-life of 2.5 ± 1.1 hours and a distribution half-life of 7.6 ± 1.9 minutes, from a 2013 study in the European Journal of Pharmaceutical Sciences, measured after an intravenous bolus in nine healthy males and averaged across three dose levels. GHRP-6 was the prototype synthetic growth hormone secretagogue, the chemical ancestor of GHRP-2, hexarelin and ipamorelin.
The two numbers describe two phases. In the first minutes after an injection, GHRP-6 spreads out of the blood into tissue and plasma concentration falls steeply. After that, a slower elimination phase takes over. A single half-life, including the one used in the table on this page, understates how fast that early drop is.
How much GHRP-6 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-6, one half-life is 2.5 hours. The rows below run that forward for a single amount with nothing added.
| Half-lives elapsed | Time elapsed | Remaining | Cleared |
|---|---|---|---|
| 1 | 2.5 hours | 50% | 50% |
| 2 | 5 hours | 25% | 75% |
| 3 | 7.5 hours | 12.5% | 87.5% |
| 4 | 10 hours | 6.25% | 93.75% |
| 5 | 12.5 hours | 3.13% | 96.88% |
| 6 | 15 hours | 1.56% | 98.44% |
| 7 | 17.5 hours | 0.78% | 99.22% |
Why do the numbers differ between sources?
GHRP-6 shows why sources can disagree without either being wrong: one that quotes minutes and one that quotes hours can both be describing the same study. The 7.6 minute distribution phase and the 2.5 hour elimination phase are both real, and which one a summary picks depends on what it is trying to say.
The wide standard deviation on the elimination figure, 1.1 hours either side of 2.5, also shows that individuals differed considerably even among nine healthy males. Our table uses the elimination value, because that is the phase that governs how long the compound lingers.
What does a half-life not tell you?
It does not cover GHRP-6's actions beyond growth hormone. It stimulates appetite through arcuate NPY and AgRP neurons, can transiently raise cortisol and prolactin, and binds the CD36 scavenger receptor, the basis of proposed cytoprotective effects seen in animal models. Each of those has its own time course.
And like every secretagogue, GHRP-6 provokes a growth hormone pulse that is a separate event from its own clearance. GHRP-6 is prohibited in sport by WADA, and whether it is detectable depends on the testing method, not on this half-life.
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-6's published value loaded. Type another figure to see how sensitive the result is to it.
Published value: 2.5 ± 1.1 hours (elimination); 7.6 ± 1.9 minutes (distribution) (Intravenous bolus) · Cabrales et al., Eur J Pharm Sci 2013 (PMID 23099431) · Compound profile
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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-6 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.
Why does GHRP-6 have two half-lives?
Because its plasma profile has two phases. After an intravenous bolus, concentration first falls with a distribution half-life of 7.6 ± 1.9 minutes as the peptide moves into tissue, then with an elimination half-life of 2.5 ± 1.1 hours. Both come from the same study.
Which GHRP-6 half-life does the table on this page use?
The elimination half-life of 2.5 hours, because it governs how long the compound remains. The single-compartment table therefore overstates how much is left in the first minutes after a dose, when the faster distribution phase dominates.
Is GHRP-6 the same as hexarelin?
No. Hexarelin is a later relative in the same family. The widely quoted 55 minute figure for hexarelin actually describes the decay of the growth hormone response, not the peptide, and no pharmacokinetic study of hexarelin itself was found in any species.
For what the evidence on GHRP-6 actually shows, read the GHRP-6 profile. For approval and regulatory position, see is GHRP-6 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.