Scientific context only. Not medical advice, not a recommendation to use.
At a glance
Synthetic hexapeptide that founded the class of growth-hormone-releasing peptides (GHRPs). Cyril Bowers identified GHRP-6 in the late 1970s as the first orally and parenterally active GH secretagogue with no structural similarity to GHRH. Never approved as a medicine; downstream analogs (GHRP-2, hexarelin, ipamorelin) were pursued clinically.
Researched for
GH stimulation in provocation testingPharmacological characterisation of the ghrelin receptorAppetite stimulation in animal models
Official status
US: Unapproved
No FDA approval as a medicine or dietary supplement. Sale as a 'research chemical' is not legally covered.
GHRP-6 is a high-affinity agonist of the growth-hormone secretagogue receptor 1a (GHSR-1a) — the same receptor later shown to bind the endogenous hormone ghrelin. The identification of GHRP-6 as a pharmacological anchor led to cloning of GHSR in 1996 and the discovery of ghrelin itself in 1999. GHRP-6 stimulates pituitary GH secretion via a pathway independent of GHRH and can be combined synergistically with GHRH. Via GHSR in the hypothalamus it additionally activates NPY/AgRP neurons, producing an orexigenic (appetite-stimulating) effect in animal models.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
4 observations · 3 tiers
Human trial
2
Animal model
1
Preclinical
1
03
What the studies show
Human trial
Mensch
Bowers CY. et al. 1990
Robust acute GH rise after single intravenous or subcutaneous administration documented in healthy volunteers and in GH-deficient patients
What does NOT follow: Acute diagnostic endpoint; chronic use has not been tested in randomised studies for clinical endpoints such as body composition.
Human trial
Mensch
Bowers CY. et al. 1990
Synergistic GH response in combination with GHRH documented — peak values exceed the sum of individual administrations
What does NOT follow: Described in provocation testing in adults and children; not part of clinical routine.
Animal model
Ratte / Maus
Orexigenic (appetite-stimulating) effect via NPY/AgRP neurons described in rodents
What does NOT follow: Translatability to humans is not supported by controlled studies for endpoints such as weight gain or cachexia.
Preclinical
in vitro / Rezeptorpharmakologie
Howard AD. et al. 1996
Identification of GHRP-6 was historically the pharmacological key to cloning the ghrelin receptor (Howard 1996) and discovering ghrelin (Kojima 1999)
What does NOT follow: Scientific-historical finding — not a clinical effect in humans.
04
Where studies disagree
Open question
Is the orexigenic (appetite-stimulating) effect of GHRP-6 clinically relevant in humans?
POSITION A
In rodent models the appetite effect via NPY/AgRP neurons is reproducibly documented; forum reports interpret this as a 'reliable hunger boost' for human use.
POSITION B
Controlled human studies on clinically relevant weight gain or lean-mass gain under GHRP-6 are missing. Acute hunger reports from provocation tests are brief and have not been evaluated for chronic use.
CURRENT STATE · The step from rodent appetite to therapeutic weight gain in humans has not been bridged. Downstream analogs (GHRP-2, anamorelin) were the therapeutic hope at this very point — anamorelin was explicitly developed for cachexia trials and partly failed clinically relevant endpoints.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 0.4 h. Pure pharmacokinetic model — not a dosing recommendation.
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Intravenous
Used as an IV bolus in provocation tests; produces the sharpest GH peak.
Subcutaneous
Also administered subcutaneously in research settings; prolonged absorption compared with IV.
Intranasal
Tested intranasally in early paediatric studies; bioavailability substantially lower.
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human trial
Transient hunger / oral dryness
Linked to ghrelin receptor activation; mostly brief and self-limiting.
berichtet in den frühen klinischen Studien
Human trial
Acute increase in prolactin and cortisol
More pronounced for GHRP-6 than for later analogs such as ipamorelin, which is more selective.
in Provokationstests beschrieben
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
No documented interactions recorded
We have not yet found robustly documented interactions for this peptide. This does NOT mean none exist — the data is limited.
08
Risks & hygiene aspects in the literature
What regulatory and scientific literature reports on risks, sterility and identity in non-pharmaceutical sources — descriptive, not a hygiene guide.
WADA status
GHRP-6 is listed on the WADA prohibited list under S2 (peptide hormones and secretagogues) — prohibited in and out of competition.
Selectivity
Compared with ipamorelin, GHRP-6 is considered less selective: concurrent rises in prolactin and cortisol are more frequently documented.
10
Anecdotal observations
Weakest evidence tier — not supported by studies
Reading note. This section gathers popular claims from communities and forums. They are explicitly marked as weakest-tier evidence. Unblinded self-reports are particularly prone to placebo, recall and confirmation biases.
Why no amounts or protocols are listed here. We deliberately show only WHAT communities report — not in what amount or how it is used. Anecdotal "doses" or "biohacker protocols" are neither verified nor standardised nor safe; publishing them would be a usage guide, which we do not provide on principle. Specific amounts belong in a conversation with a doctor, not in a forum.
Bodybuilding forums often describe GHRP-6 as a 'budget variant' of other GHRPs, paired with Mod-GRF/CJC-1295.
widespread in English- and Russian-language forums
Not supported by studies: Off-label forum use is not supported by any controlled human study for endpoints such as muscle gain or body composition; the source (powder market) is not regulatorily controlled.
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Legal status by country
Country
Status
Note
Checked
United States
Unapproved
No FDA approval as a medicine or dietary supplement. Sale as a 'research chemical' is not legally covered.
2026-05-22
Germany
Unapproved
No EMA/BfArM approval. Bringing to market as an unapproved medicinal product is prohibited under §21 AMG. WADA-prohibited under S2.
2026-05-22
United Kingdom
Unapproved
No MHRA approval. WADA-prohibited.
2026-05-22
JP
Unapproved
Unlike GHRP-2 (approved in Japan as GHRP Kaken for diagnostics), GHRP-6 is not approved as a medicine in Japan.
2026-05-22
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
1Enter the vial's substance amount (printed on the label).
2Enter how much solvent you add.
3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.