GHRP-6 peptide: what the endocrine studies and the Cuban stroke trial measured, why it makes you hungry, and what was never tested
What 738 indexed publications and 22 randomized trials actually state about ghrp-6, sentence by sentence, each tied to its source and labeled by the kind of evidence it is.
At a glance
What GHRP-6 is, and what the endocrine studies actually measured
GHRP-6 is a peptide in the ghrelin mimetics class (ghrelin receptor (GHS-R1a) agonist). Europe PMC indexes 738 publications naming it or a listed alias in a title or abstract, including 22 randomized controlled trials and 41 clinical trials of any design, as of . The strongest evidence tier in that literature is human clinical trials.
This page reports what those studies state, sentence by sentence, with each statement tied to its source and labeled by the kind of evidence it is. It does not recommend use, and it does not translate study doses into anything personal.
What the evidence level means
Publication counts show what is indexed, not how strong the evidence is. The ledger below separates human clinical records from preclinical, analytical, and in-vitro work.
Interpretation boundary: An indexed publication count is a discovery measure. It does not establish efficacy, safety, approval, or a personal treatment plan.
GHRP-6 in two minutes
What it is. The first growth hormone releasing peptide, a six-amino-acid ghrelin mimic from 1984 whose receptor search discovered ghrelin itself. It makes the pituitary release a pulse of growth hormone and makes people hungry, by the same mechanism.
What the research actually shows. 738 indexed publications, most of them 1990s endocrinology: single intravenous doses raise growth hormone within an hour, far more when combined with GHRH, and also raise ACTH, cortisol and prolactin. The GHRH plus GHRP-6 test was validated as a diagnostic for growth hormone deficiency in 250 people. A Cuban phase 3 trial gave GHRP-6 with EGF to 95 stroke patients for seven days and found no difference in disability.
What was never measured. Muscle, fat, strength or recovery in people, by any route, over any period. No human study in the ledger used subcutaneous injection.
Status. Never approved. Named on the WADA list under S2. Its cousin GHRP-2 is a Japanese diagnostic; its cousin ipamorelin is the one people switched to for less cortisol and hunger.
Where the evidence is thinnest. Everything about the way it is used: subcutaneous, three times a day, for months.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
How it works
Written from general pharmacology and the development record, and marked as editorial synthesis; the measurements behind it are quoted in the biomarker section.
- Editorial synthesis from general knowledge
- Editorial synthesis from general knowledge
- Editorial synthesis from general knowledge
What happened in the human studies?
This record's ledger holds 12 primary human studies, of which 12 are trials. Few enough to show in full: each card quotes what its abstract reported about GHRP-6. Read them before any other section on this page.
-
In the intention-to-treat population, no differences were found in mRS, Barthel index nor survival.
Sourcepmid-42462342· quoted verbatim from the abstract -
Disposition of GHRP-6 best fitted a bi-exponential function with R(2) higher than 0.99, according to a mathematic modeling and confirmed by an Akaike index (AIC) lower than that of the corresponding one-compartment model for all subjects.
Sourcepmid-23099431· quoted verbatim from the abstract -
When analyzing Δ area under the curve (ΔAUC) GH values after ghrelin, GHRP-6, and GHRH, no significant differences were observed in T1DM compared with controls.
Sourcepmid-20189610· quoted verbatim from the abstract -
GHRP-6-induced ACTH release also increased (before: 60.7 +/- 17.2; 6th month: 78.5 +/- 12.1), although not significantly.
Sourcepmid-19453623· quoted verbatim from the abstract -
Peak GH response to GHRH+GHRP-6 during the hyperglycemic clamp was lower than in the englycemic clamp (112.45+/-14.45 mU/l versus 151.06+/-16.87 mU/l; P<0.05).
Sourcepmid-14693411· quoted verbatim from the abstract -
Inclusion criteria were severe GH deficiency--ie, a GH peak after ITT of Findings GH peaks seen after the GHRH/GHRP-6 test did not result in any side-effects and were not affected by age, sex, amount of adipose tissue, or by the GH assay system used.
Sourcepmid-11030292· quoted verbatim from the abstract -
The association of the two peptides markedly increased GH levels (peak: 172.4 +/- 34.2; AUC: 10393.0 +/- 1894.8) compared with the isolated administration of GHRP-6 or GHRH.
Sourcepmid-10583306· quoted verbatim from the abstract -
GHRP-6 i.n. prompted a significant increase in GH concentration during the total night and a trend toward an increase in ACTH secretion during the first half of the night, whereas cortisol secretion remained unchanged.
Sourcepmid-10336729· quoted verbatim from the abstract -
In normal subjects, GH secretion was 1029 +/- 202 after GHRH treatment, 1221 +/- 345 after GHRP-6, and 3542 +/- 650 after GHRH plus GHRP-6; the latter value was significantly (P < 0.05) higher than the secretion elicited by GHRH or GHRP-6 alone.
Sourcepmid-7593423· quoted verbatim from the abstract -
Growth hormone-releasing peptide 6 (GHRP-6) is a synthetic hexapeptide with a potent GH-releasing activity after intravenous, subcutaneous, intranasal and oral administration in man.
Sourcepmid-7581965· quoted verbatim from the abstract -
In the group of young adult subjects the combined administration of GHRH and GHRP-6 elicited a greater GH increase than GHRH alone (F = 21.9, P Conclusions These data show that GH responses to GHRP-6 are much greater than to GHRH in late adulthood.
Sourcepmid-7734029· quoted verbatim from the abstract -
Small transient increases in cortical and PRL were observed (increases in cortical averaged 182.1 +/- 33.1 nmol/L and peak PRL was 21 +/- 2.6 micrograms/L after 1.0 mg/kg L-692,429, respectively), whereas no significant changes occurred in LH, FSH, TSH, insulin, or glucose concentrations.
Sourcepmid-8077339· quoted verbatim from the abstract
Study by study: what GHRP-6 did in people
Every human study in the ledger, with what was given and what was measured. The pattern is hormones after one dose.
| Study | Participants | Dose and route | What was measured | Result |
|---|---|---|---|---|
| Popovic 2000 (diagnostic validation) | 125 adults with pituitary disease, 125 healthy controls | GHRH 1 mcg/kg + GHRP-6 1 mcg/kg IV | Peak GH over 120 min vs insulin tolerance test | The combined test separated deficient from healthy as well as the standard test, more conveniently |
| Hernández-Bernal 2026 (COURAGE-2, phase 3) | 188 acute stroke patients (95 treated, 93 standard care) | EGF 75 mcg + GHRP-6 5 mg IV, twice daily, 7 days | Disability at 3 and 6 months | No difference in Rankin or Barthel scores in the intention-to-treat analysis |
| Cabrales 2013 (pharmacokinetics) | 9 healthy men | 100, 200, 400 mcg/kg IV bolus | Plasma GHRP-6 over 12 hours | Two-phase decline; measurable at 12 hours |
| Frieboes 1999 (sleep and routes) | Healthy young men | 300 mcg/kg oral; 30 mcg/kg intranasal or sublingual | Overnight GH, ACTH, cortisol, sleep EEG | Oral did nothing; intranasal raised GH all night; earlier IV boluses had raised ACTH and cortisol |
| Pinto 1999 | 16 healthy adults | 1 mcg/kg IV, with or without GHRH and dexamethasone | GH response | Acute dexamethasone enhanced the GH response to GHRP-6 |
| Micic 1995 | Healthy young and older adults | 90 mcg IV alone or with GHRH 100 mcg | GH response | The response did not decline with age when GHRP-6 was given, alone or combined |
| Micic 2004 | 12 men with type 2 diabetes | GHRH + GHRP-6, 100 mcg each, IV | GH under euglycaemic and hyperglycaemic clamps | High glucose blunted the GH peak |
| Bellone 1995 | 13 children with short stature | 300 mcg/kg oral, with or without arginine | GH response | Oral GHRP-6 released GH; the abstract compares it with IV GHRH |
| Pombo 1995 | Children with neonatal pituitary stalk transection | GHRH, GHRP-6 or both | GH response | No GH release by any route: GHRP-6 needs an intact hypothalamus |
| Correa-Silva 2010 | 8 patients with Cushing's disease, 11 controls | GHRP-6 and ghrelin, before and after ketoconazole | ACTH and cortisol | Exaggerated ACTH response, larger after six months of ketoconazole |
| de Sá 2010 | 9 patients with type 1 diabetes, 9 controls | Ghrelin, GHRP-6 and GHRH | GH, ACTH, cortisol | Ghrelin released more GH than GHRP-6 or GHRH in both groups |
| Gertz 1993 | 24 healthy men | L-692,429, a non-peptide GHRP-6 mimic, IV | GH, cortisol, prolactin | Dose-dependent GH; small transient cortisol and prolactin rises |
Nothing in this table is a body-composition result. The literature that made GHRP-6 famous is about how growth hormone is regulated, and it used the peptide as a probe.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
What the evidence shows
One row per primary study in this record's ledger. Fields are read from each paper's indexing and abstract. "Analytical method" marks papers about detecting or measuring the compound rather than about its effects.
| Study | Design | n | Species | Dose | Route | Duration | Reported outcome | Tier |
|---|---|---|---|---|---|---|---|---|
| Hernández-Bernal 2026 | Randomized controlled trial | 95 | Humans | — | — | 7 days; 3 years | In the intention-to-treat population, no differences were found in mRS, Barthel index nor survival. | Human clinical trial |
| Cabrales 2013 | Phase 1 clinical trial | — | Humans | — | — | — | Disposition of GHRP-6 best fitted a bi-exponential function with R(2) higher than 0.99, according to a mathematic modeling and confirmed by an Akaike index (AIC) lower than that of the corresponding one-compartment… | Human clinical trial |
| de 2010 | Randomized controlled trial | 9 | Humans | — | — | — | When analyzing Δ area under the curve (ΔAUC) GH values after ghrelin, GHRP-6, and GHRH, no significant differences were observed in T1DM compared with controls. | Human clinical trial |
| Correa-Silva 2010 | Randomized controlled trial | — | Humans | — | — | 6 months | GHRP-6-induced ACTH release also increased (before: 60.7 +/- 17.2; 6th month: 78.5 +/- 12.1), although not significantly. | Human clinical trial |
| Micic 2004 | Clinical trial | — | Humans | 100 mcg | intravenous | — | Peak GH response to GHRH+GHRP-6 during the hyperglycemic clamp was lower than in the englycemic clamp (112.45+/-14.45 mU/l versus 151.06+/-16.87 mU/l; P<0.05). | Human clinical trial |
| Popovic 2000 | Clinical trial | — | Humans | — | intravenous | — | Inclusion criteria were severe GH deficiency--ie, a GH peak after ITT of Findings GH peaks seen after the GHRH/GHRP-6 test did not result in any side-effects and were not affected by age, sex, amount of adipose tissue,… | Human clinical trial |
| Pinto 1999 | Randomized controlled trial | — | Humans | — | intravenous, oral | — | The association of the two peptides markedly increased GH levels (peak: 172.4 +/- 34.2; AUC: 10393.0 +/- 1894.8) compared with the isolated administration of GHRP-6 or GHRH. | Human clinical trial |
| Frieboes 1999 | Clinical trial | — | Humans | — | intravenous, oral | — | GHRP-6 i.n. prompted a significant increase in GH concentration during the total night and a trend toward an increase in ACTH secretion during the first half of the night, whereas cortisol secretion remained unchanged. | Human clinical trial |
| Pombo 1995 | Controlled clinical trial | — | Humans | — | intravenous | — | In normal subjects, GH secretion was 1029 +/- 202 after GHRH treatment, 1221 +/- 345 after GHRP-6, and 3542 +/- 650 after GHRH plus GHRP-6; the latter value was significantly (P < 0.05) higher than the secretion… | Human clinical trial |
| Bellone 1995 | Controlled clinical trial | 7 | Humans | — | intranasal, intravenous, oral, subcutaneous | — | — | Human clinical trial |
| Micic 1995 | Randomized controlled trial | 9 | Humans | — | intravenous | — | In the group of young adult subjects the combined administration of GHRH and GHRP-6 elicited a greater GH increase than GHRH alone (F = 21.9, P Conclusions These data show that GH responses to GHRP-6 are much greater… | Human clinical trial |
| Gertz 1993 | Clinical trial | 8 | Humans | — | intravenous | — | Small transient increases in cortical and PRL were observed (increases in cortical averaged 182.1 +/- 33.1 nmol/L and peak PRL was 21 +/- 2.6 micrograms/L after 1.0 mg/kg L-692,429, respectively), whereas no… | Human clinical trial |
| Risco-Acevedo 2026 | Animal study | 6 | Mice | — | — | — | In aged animals, EGF + GHRP6 treatment increased step length (p = 0.04). | Animal, preclinical |
| Rodríguez-Ulloa 2026 | Animal study | 12 | Rats | — | — | — | At 24 h post-treatment, proteins associated with reactive oxygen species (ROS) detoxification, heat shock factor 1 (HSF1) activation, and negative regulation of cellular hypoxia response were significantly modulated. | Animal, preclinical |
| Yunjia 2026 | Animal study | — | Mice | — | — | — | YJP improved cardiac dysfunction and myocardial fibrosis and markedly ameliorated depressive behaviors. | Animal, preclinical |
| Wang 2026 | Animal study | — | Rats | — | — | 7 days | Here, we show that GHRP-6 attenuated myocardial tissue demise, reduced myocardial interstitial fibrosis/scarring, and integrally improved left ventricle physiology. | Animal, preclinical |
| Zhao 2025 | Animal study | — | Mice | — | — | — | — | Animal, preclinical |
| Zhu 2025 | Animal study | — | Mice | — | — | — | Compared with the E. granulosus (Eg) group, the GHSR-KO group presented a significant reduction in the number of liver infection foci. | Animal, preclinical |
| Castro 2025 | Animal study | — | Dogs | — | — | — | Hypersalivation, hypoactivity, reduced heart rate, changes in respiration, pale gums and erythema of the head region were observed in some animals administered at 1000 and 2000 μg/kg/day. | Animal, preclinical |
| Ayman 2025 | Animal study | — | Rats | — | — | — | On the eighth day, in nicotine-treated rats a significant hyperactivity was observed, that was reduced significantly by ghrelin and GHRP-6. | Animal, preclinical |
| Poelman 2025 | Animal study | — | Mice | 5 mg/kg | intranasal | — | Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos… | Animal, preclinical |
| Wu 2025 | Animal study | — | Mice | — | — | — | EM-1-DLS demonstrated the highest antinociceptive potency among the peptides, with an ED 50 approximately 8-fold greater than EM-1, while EM-2-DLS showed comparable effects to EM-2. | Animal, preclinical |
| Elimam 2024 | Animal study | — | Mice | — | — | — | — | Animal, preclinical |
| Zhu 2024 | Animal study | — | Mice | — | — | — | Serum Ghrelin levels were increased in E.g-infected 4- and 12-week mice, and reduced in 36-week mice. | Animal, preclinical |
Doses reported in studies
Each entry is a sentence quoted from the study's abstract, with the study's design, sample size and year in front of it. Comparator doses in the same sentence are not attributed to ghrp-6.
- Source
pmid-11030292 - Source
pmid-10336729 - Source
pmid-10583306 - Source
pmid-7734029 - Source
pmid-14693411 - Source
pmid-7581965 - Source
pmid-23099431 - Source
pmid-42462342 - Doses stated in the abstract: 5 mg/kg
Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope.
Sourcepmid-39813130· quoted verbatim from the abstract, emphasis added - Doses stated in the abstract: 400 μg
Treatments for both species were based on a CMC jelly composition containing GHRP-6 400 μg/mL.
Sourcepmid-27200188· quoted verbatim from the abstract, emphasis added
Every GHRP-6 dose in the studies, in one table
Every figure here was given in a study, almost always as a single intravenous dose. No human study in the ledger injected it under the skin.
| Setting | Route | Dose | Schedule | Population |
|---|---|---|---|---|
| Diagnostic test | Intravenous bolus | 1 mcg/kg, with GHRH 1 mcg/kg | Single | Adults with suspected GH deficiency |
| Endocrine studies | Intravenous bolus | 1 mcg/kg; 90 to 100 mcg fixed | Single | Healthy adults; diabetes; Cushing's disease |
| Pharmacokinetics | Intravenous bolus | 100, 200, 400 mcg/kg | Single | 9 healthy men |
| Sleep and route study | Oral capsules; intranasal; sublingual | 300 mcg/kg oral; 30 mcg/kg nasal or sublingual | Single, evening | Healthy young men |
| Children | Oral | 300 mcg/kg | Single | Short stature |
| Stroke (COURAGE-2) | Intravenous | 5 mg with EGF 75 mcg | Twice daily, 7 days | Acute ischaemic stroke |
| Mice (2025) | Intranasal | 5 mg/kg | Single | Food-intake study |
| Rabbits and rats (2016) | Local and systemic | 400 mcg | Repeated | Hypertrophic scar and wound models |
Figures for subcutaneous GHRP-6 circulate on forums and vendor pages. None was given to a person in any study in the ledger, so none is reproduced here; the table holds every dose a study actually administered. Note that the stroke trial's 5 mg twice daily, by vein, is orders of magnitude above the endocrine doses and was a different use entirely.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
Side effects: cortisol, prolactin, hunger, and what was never measured
Cortisol and prolactin rise with GHRP-6 in the studies that measured them, more than with ipamorelin; hunger is its signature. Beyond single-dose endocrine work and one 7-day stroke trial, no safety data exist for the way it is used. Events and their frequency as each study reported them, with the denominator where the abstract gives one.
- Source
pmid-10336729 - Source
pmid-19453623 - Source
pmid-8077339 - Source
pmid-42462342 - Editorial synthesis from general knowledge
-
The present study aimed to investigate the impacts of ghrelin and GHRP-6 on the horizontal and vertical activity in rats exposed to chronic nicotine treatment followed by acute nicotine withdrawal.
Sourcepmid-39857727· quoted verbatim from the abstract -
Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope.
Sourcepmid-39813130· quoted verbatim from the abstract
Who GHRP-6 is discussed for, and the cautions that recur
Studied: healthy adults and children in single-dose endocrine tests; adults with pituitary disease, diabetes and Cushing's disease as diagnostic or physiological probes; acute stroke patients in Cuba. Never studied: anyone dosed subcutaneously, anyone dosed for muscle or fat, anyone dosed for more than seven days. Community: bodybuilders, people wanting to gain weight, and people using it for sleep.
The cautions come from the mechanism and the endocrine data:
- Cortisol and prolactin. Both rise with GHRP-6, more than with ipamorelin; the response is exaggerated in Cushing's disease. Anyone with a mood, adrenal or prolactin-related condition is on the wrong side of this compound's selectivity.
- Blood sugar. High glucose blunts the GH response, and growth hormone itself raises glucose; no study measured glucose over repeated dosing.
- Hunger and weight. The mechanism drives food intake; whether that becomes weight gain in people is unmeasured, and for many users it is the point.
- Anyone without an intact hypothalamus. It does nothing after stalk transection, which also means its effects depend on a working axis that steroids and other drugs alter.
- Cancer and growth-sensitive conditions. Repeated GH and IGF-1 stimulation is the class concern; no study of GHRP-6 addressed it.
- Tested athletes. Named on the WADA list under S2; detection methods exist.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
Biomarkers measured in studies
Laboratory and clinical measures the studies report tracking, including which hormones did and did not change.
-
Combined therapy of Epidermal Growth Factor (EGF) and Growth Hormone Releasing Peptide-6 (GHRP6) has shown potential benefits in stroke patients.
Sourcepmid-42462342· quoted verbatim from the abstract -
GHRP-6 is a growth hormone secretagogue that also enhances tissue viability in different organs.
Sourcepmid-23099431· quoted verbatim from the abstract -
Ghrelin is a GH secretagogue that also increases adrenocorticotropic hormone (ACTH) and cortisol levels, similarly to GH-releasing peptide-6 (GHRP-6).
Sourcepmid-20189610· quoted verbatim from the abstract -
In Cushing's disease (CD), adrenocorticotrophic hormone (ACTH)/cortisol responses to growth hormone secretagogues (GHS), such as ghrelin and GHRP-6, are exaggerated.
Sourcepmid-19453623· quoted verbatim from the abstract -
The aim of this study was to investigate the effect of two different glucose levels on GH response to the combined administration of GHRH+GHRP-6 in patients with type 2 diabetes.
Sourcepmid-14693411· quoted verbatim from the abstract
Reported interactions
Sentences in which the compound is studied alongside another agent. Read the quotation: the word interaction can also be statistical.
-
As the GHRH-induced GH rise in children is potentiated by arginine (ARG), even when administered by oral route at low dose (4 g), we studied also the interaction of oral GHRP-6 and ARG administration.
Sourcepmid-7581965· quoted verbatim from the abstract -
The marked increase of plasma GH levels observed after administration of GHRP-6 alone or in combination with GHRH indicates that impaired GH secretion in late adulthood is a functional and potentially reversible state.
Sourcepmid-7734029· quoted verbatim from the abstract
Reported timelines
Onset, peak and duration figures as each study reported them.
- Source
pmid-23099431 - Source
pmid-10336729 - Source
pmid-42462342 -
Here we examined whether GHRP-6 administration concomitant to Dox prevented the onset of DCM/HF and multiple organs damages in otherwise healthy rats.
Sourcepmid-38873418· quoted verbatim from the abstract -
Importantly, in the hypertrophic scars rabbit's model, GHRP-6 intervention dramatically reduced the onset of exuberant scars by activating PPARγ and reducing the expression of fibrogenic cytokines.
Sourcepmid-27200188· quoted verbatim from the abstract -
Four different doses of rhEGF, GHRP-6 and these combined agents were intraperitoneally administered immediately after the onset of reperfusion.
Sourcepmid-26311576· quoted verbatim from the abstract -
GHRP-6 was injected [intraperitoneal (IP) or intracerebroventricular (ICV)] 2 h before the onset of stress to observe its potential prevention of the mucosal lesion.
Sourcepmid-22791951· quoted verbatim from the abstract
What is measured over time, and what is not
The literature measures minutes and hours. A growth hormone pulse peaks within the first hour after an intravenous bolus and the diagnostic test samples for 120 minutes; the peptide itself was still measurable at 12 hours after large intravenous doses; intranasal dosing raised growth hormone across one night. The longest exposure in any human study is seven days, in the stroke trial, which measured disability at six months and found none of the hoped-for difference. Nothing has been measured over the weeks and months of use the community describes, and the three-times-daily pattern is an inference from the pulse duration, not a studied schedule.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
Study durations
Treatment and follow-up periods as stated in each abstract.
- Durations stated: 7 days; 3 years; 6 months
Participants received the combined therapy (n=95; twice daily, 7 days) or standard care (n=93).
Sourcepmid-42462342· quoted verbatim from the abstract, emphasis added - Durations stated: 6 months
Design/patients Eight untreated patients with CD (BMI: 28.5 +/- 0.8 kg/m(2)) were evaluated before and after 3 and 6 months of ketoconazole treatment and compared with 11 controls (BMI: 25.0 +/- 0.8).
Sourcepmid-19453623· quoted verbatim from the abstract, emphasis added - Durations stated: 7 days
Treatments were initiated post-surgery and continued for 7 days.
Sourcepmid-41901314· quoted verbatim from the abstract, emphasis added - Durations stated: 5 days; 30 days
Excisional full-thickness wounds (6 mmØ) were created in the dorsum of Wistar rats and topically treated twice a day for 5 days.
Sourcepmid-27200188· quoted verbatim from the abstract, emphasis added
Routes: intravenous in the studies, oral and nasal once, subcutaneous only on vendor pages
Intravenous bolus in almost every human study; oral capsules and a nasal spray in one sleep study; intravenous in the stroke trial. No human study in the ledger gave GHRP-6 by subcutaneous injection, the route it is sold for. Routes of administration named in each study.
- administration by intravenous route reported
GH response to i.v. bolus of GHRH+GHRP-6 (100 mcg, each) was measured in 12 male patients with type 2 diabetes (mean age: 53.9+/-1.59 years; BMI: 25.58+/-0.39 kg/m(2); mean HbA(1c): 8.7+/-0.42%), during a euglycemic (mean glucose: 4.92+/-0.08 mmol) hyperinsulinemic clamp (insulin infusion rate of 100 mU/kg/h) and a hyperglycemic clamp (mean glucose: 12.19+/-0.11 mmol/l).
Sourcepmid-14693411· quoted verbatim from the abstract - administration by intravenous route reported
All cases and controls were given GHRH 1 microg per kg bodyweight intravenously plus GHRP-6 1 microg per kg intravenously at 0 min and blood samples were obtained during a subsequent 120 min period.
Sourcepmid-11030292· quoted verbatim from the abstract - administration by intravenous, oral route reported
One group of subjects received iv GHRP-6 (1 microg/kg), GH-releasing hormone (GHRH; 100 microg), GHRH plus GHRP-6 or saline 3.5 h after oral acute dexamethasone administration (4 mg; at 0600 h).
Sourcepmid-10583306· quoted verbatim from the abstract - administration by intravenous, oral route reported
After repeated intravenous (i.v.) boluses of growth hormone-releasing peptide-6 (GHRP-6) we found recently increases of growth hormone (GH), corticotropin (ACTH) and cortisol levels and of the amount of stage 2 sleep.
Sourcepmid-10336729· quoted verbatim from the abstract - administration by intravenous route reported
The subjects underwent 3 different tests on separate occasions, being challenged with GHRH (1 microgram/kg, iv), GHRP-6 (1 microgram/kg, iv), or GHRH plus GHRP-6.
Sourcepmid-7593423· quoted verbatim from the abstract
Weight-normalized doses, as published
Per-kilogram figures exactly as each study published them, for the species it studied.
- Source
pmid-11030292 - Source
pmid-23099431 - Weight-normalized doses as published: 5 mg/kg
Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope.
Sourcepmid-39813130· quoted verbatim from the abstract, emphasis added
Weight-normalized figures above are reproduced exactly as each study published them, for the species it studied. Dose does not scale linearly with body mass between species: metabolic rate, clearance and receptor density differ, and regulatory guidance uses allometric, not proportional, conversion. A mg/kg figure from a rat study is a fact about that rat study and nothing else.
What people report outside the literature
Forum reports describe intense hunger within minutes, water retention, tiredness and a warm flush, with three-times-daily injection for months. None of the studies used that pattern, and none measured what months of ghrelin-receptor stimulation does. What circulates in user communities and clinic marketing, reported so a reader knows the figures and their origin. None of it has been tested in a trial, and none of it is a suggestion.
- Editorial synthesis from general knowledge
Reconstitution mathematics
Lyophilised peptide is supplied as a mass in a vial and dissolved in a stated volume of diluent. Two figures follow from that and nothing else:
- Concentration = mass in vial ÷ diluent volume. A 5 mg vial in 2 mL is 2.5 mg/mL, or 2,500 mcg/mL.
- Volume for a given mass = that mass ÷ concentration. 250 mcg at 2,500 mcg/mL is 0.1 mL. On a U-100 insulin syringe, where 1 mL is 100 units, that is 10 units.
Study doses on this page are quoted as published, in the units the authors used. Converting between mcg, mg and IU, or between a mass and a syringe volume, is arithmetic; deciding a mass is not, and this page does not do it. The reconstitution calculator performs the conversion with the formula shown.
Reading a certificate of analysis
A certificate of analysis is a laboratory report on one batch. Reading it means checking four things in order.
- Identity. Mass spectrometry should report an observed molecular mass matching the peptide's theoretical mass within the instrument's stated tolerance. A certificate with no mass spectrometry, or one that lists only the expected value, has not confirmed identity.
- Purity. HPLC purity is the area of the main peak as a share of all peaks, at a stated wavelength. It says nothing about what the other peaks are, and it is not a measure of quantity.
- Quantity. Net peptide content, by amino acid analysis or UV, is the fraction of the vial's mass that is peptide rather than counter-ions and water. A 5 mg vial at 80% net content holds 4 mg of peptide, and every concentration figure above changes accordingly.
- Provenance. The batch number on the certificate should match the vial, the laboratory should be named and independent of the seller, and the test date should be recent.
This page rates no supplier and links to none. It describes how to read the document.
Equipment described in studies
Published human studies of injectable peptides report the same small set of materials: single-use insulin syringes with fixed needles, most often U-100 with 29 to 31 gauge needles; bacteriostatic water or sterile water for injection as diluent, with the choice stated in the methods; alcohol swabs; and refrigerated storage of reconstituted solution. Animal studies more often report intraperitoneal or intragastric administration and state the vehicle used. Where a study in this record's ledger names its materials or vehicle, that sentence appears under storage or routes above; where it does not, nothing is assumed here.
Storage and handling
Anti-doping laboratories have studied GHRP-6's stability in serum and its degradation products for detection purposes; the peptide degrades in liquid samples over days. That is analytical chemistry, not a vial instruction. Vendor sheets follow general lyophilised-peptide practice; contents are unverified.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
Common mistakes in how GHRP-6 is discussed
- Reading the endocrine literature as efficacy data. Hundreds of papers used GHRP-6 as a probe of growth hormone regulation. None measured muscle or fat in people.
- Calling hunger a side effect. It is the mechanism: GHRP-6 is a ghrelin mimic, and ghrelin is the hunger hormone. A user who does not want to eat more has chosen the wrong GHRP.
- Assuming the subcutaneous schedule is studied. Every human study in the ledger dosed intravenously, orally or nasally, once. The three-times-daily pattern is community practice.
- Confusing it with its antagonist. [D-Lys3]-GHRP-6 blocks the ghrelin receptor and appears in many papers; it is a different molecule with the opposite effect, and automated searches pull it in.
- Treating GHRP-2's Japanese approval as GHRP-6's. Pralmorelin (GHRP-2) is approved in Japan as a diagnostic; GHRP-6 is approved nowhere.
- Missing the stroke trial. The only phase 3 of GHRP-6 was in acute stroke, with EGF, and it was negative on its primary endpoint.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
GHRP-6 vs GHRP-2, ipamorelin, hexarelin and MK-677
| Compound | What it is | GH release and selectivity | Status |
|---|---|---|---|
| GHRP-6 | First GHRP (1984); hexapeptide | Strong GH pulse; raises ACTH, cortisol and prolactin; strongest hunger | Not approved; WADA S2 |
| GHRP-2 (pralmorelin) | Second-generation GHRP | More potent GH release than GHRP-6 in comparative studies; also raises cortisol and prolactin | Approved in Japan as a diagnostic; no record on this site |
| Ipamorelin | Pentapeptide designed for selectivity; 63 indexed publications, 2 randomized trials | GH release with little cortisol or prolactin effect and less hunger | Not approved; WADA S2 |
| Hexarelin | Hexapeptide GHRP-6 analogue | Potent GH release; desensitises with repeated dosing; cardiac studies | Not approved; no record on this site |
| MK-677 (ibutamoren) | Oral non-peptide ghrelin mimetic | Sustained GH and IGF-1 rise over 24 hours; raises appetite and glucose; heart-failure signal in one trial | Not approved; no record on this site |
| CJC-1295 (the usual stacking partner) | GHRH analogue, a different receptor; 37 indexed publications | Synergistic GH release with any GHRP, as the GHRH + GHRP-6 test demonstrates | Not approved; WADA S2 |
The comparison that has actually been run in people is GHRP-6 against GHRH and against ghrelin, in the endocrine studies above; the comparisons among GHRPs come from separate studies and from the pharmacology that motivated each successor. This site's ipamorelin vs GHRP-6 page lines the two records up side by side, and the CJC-1295 and ipamorelin page holds the GHRH-plus-GHRP evidence.
Editorial synthesis Written from general pharmacology, the development record and what is commonly reported; not a cited finding. Cited findings on this page carry their own tier.
Exclusion criteria in studies
Who each trial excluded, as stated in the abstract.
-
Inclusion criteria were severe GH deficiency--ie, a GH peak after ITT of Findings GH peaks seen after the GHRH/GHRP-6 test did not result in any side-effects and were not affected by age, sex, amount of adipose tissue, or by the GH assay system used.
Sourcepmid-11030292· quoted verbatim from the abstract
Other compounds in its class
Same class in the registry: Ipamorelin. Each row shows what that compound's own record states; nothing is inferred across rows. Head-to-head evidence, where any exists, is on the comparison page: Ipamorelin vs GHRP-6.
| Compound | Tier | Publications | RCTs | Record |
|---|---|---|---|---|
| GHRP-6 | Human clinical trial | 738 | 22 | draft |
| Ipamorelin | Human clinical trial | 63 | 2 | draft |
Regulatory status: never approved, named by WADA, a diagnostic relative approved in Japan
Registry facts only. Jurisdiction-level status, compounding categories and sport prohibitions need their own cited documents before they appear here.
- Editorial synthesis from general knowledge · primary document to be added to the ledger
Open questions and limitations
What is genuinely unknown, stated plainly. A missing field is not evidence that the outcome is safe, effective, or established.
- No human study in the ledger gave GHRP-6 subcutaneously or for longer than seven days, and none measured body composition, strength or recovery.
- The 2013 pharmacokinetic half-life figures and the 1980s and 1990s dose-response papers (Bowers 1984 onward) are not in the ledger.
- The Cuban CIGB programme's earlier-phase results for cardioprotection and stroke are not indexed.
Questions people ask
Why does GHRP-6 cause hunger?
Because it is a ghrelin mimic. Ghrelin is the stomach's hunger hormone, and GHRP-6 was the compound that led to the discovery of its receptor; activating that receptor in the hypothalamus drives food intake, which is why a 2025 mouse study chose GHRP-6 as the tool to engage the brain's ghrelin system and why hunger is the first thing users report. The effect is the mechanism, not a side effect of it.
What is GHRP-6?
GHRP-6 is a six-amino-acid synthetic peptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) described by Cyril Bowers in 1984, the first growth hormone releasing peptide. It acts on the ghrelin receptor to make the pituitary release growth hormone, and its discovery led to the identification of that receptor and of ghrelin itself. It has been used as a research tool and a diagnostic test agent, never approved as a medicine, and is sold as a research chemical.
What is the half-life of GHRP-6?
Short. A 2013 pharmacokinetic study gave nine men single intravenous boluses of 100, 200 and 400 micrograms per kilogram and found a two-phase decline with the peptide still measurable at 12 hours; the half-life figures are in the full text, not the abstract. The growth hormone pulse it triggers lasts about an hour, which is why the community injects it several times a day.
Does GHRP-6 increase weight?
No human study has measured body weight or composition after GHRP-6. It increases hunger, which is why the community expects weight gain and why a 2025 mouse study found intranasal GHRP-6 increased food intake; whether the growth hormone pulses change body composition in people has never been tested.
Has GHRP-6 been tested in humans?
Extensively, but as a probe rather than a treatment: single intravenous doses in healthy adults, children and patients to study growth hormone regulation; a 250-person validation of the GHRH plus GHRP-6 diagnostic test; one oral and nasal sleep study; and a Cuban phase 3 trial of GHRP-6 with EGF in 188 stroke patients, which found no difference in disability. No study measured muscle, fat or recovery.
What dose was used in the studies?
One microgram per kilogram intravenously in the diagnostic test and most endocrine work, 90 to 100 micrograms as fixed boluses, 100 to 400 micrograms per kilogram in the pharmacokinetic study, 300 micrograms per kilogram orally and 30 intranasally in the sleep study, and 5 mg intravenously twice daily with EGF in the stroke trial. No human study in the ledger gave it subcutaneously.
Why does GHRP-6 make you hungry?
Because it is a synthetic ghrelin: it activates the receptor for the stomach's hunger hormone in the hypothalamus, the same action that releases growth hormone. Hunger is the mechanism working, not a side effect, and it is the trait the later GHRPs, especially ipamorelin, were designed to reduce.
Does GHRP-6 raise cortisol and prolactin?
Yes. Repeated intravenous boluses raised ACTH and cortisol alongside growth hormone in healthy men, the ACTH response is exaggerated in Cushing's disease, and a non-peptide mimic produced small transient cortisol and prolactin rises. This is the selectivity gap between GHRP-6 and ipamorelin.
What are the side effects of GHRP-6?
In the studies: hunger, cortisol and prolactin rises, and, from the class, water retention and tingling that the abstracts do not detail. Nothing has been measured beyond single doses and one seven-day trial, so the effects of months of use, including on glucose and weight, are unknown.
Is GHRP-6 FDA approved?
No, and it has never been approved anywhere. Its relative GHRP-2 is approved in Japan as a diagnostic for growth hormone deficiency; GHRP-6 has been used the same way in research without registration.
Is GHRP-6 banned in sport?
Yes. WADA names GHRP-6 on the Prohibited List under S2 as a growth hormone secretagogue, prohibited at all times, and anti-doping laboratories publish detection and stability methods for it.
What is the difference between GHRP-6 and ipamorelin?
Same receptor, different selectivity. GHRP-6 releases growth hormone and also ACTH, cortisol and prolactin, and drives hunger strongly; ipamorelin was designed to release growth hormone with little of the rest. This site's ipamorelin-vs-GHRP-6 comparison page lines the two records up.
What is the difference between GHRP-6 and GHRP-2?
GHRP-2 (pralmorelin) is the more potent successor and is approved in Japan as a diagnostic agent; it also raises cortisol and prolactin and stimulates appetite, somewhat less than GHRP-6. No head-to-head trial for any clinical outcome exists.
Can GHRP-6 be taken orally or as a nasal spray?
Both were tested once, in healthy young men: 300 micrograms per kilogram in enteric-coated capsules did nothing to overnight hormones, while 30 micrograms per kilogram intranasally raised growth hormone across the night. Oral dosing in children with short stature did release growth hormone in a 1995 study.
What was the GHRP-6 stroke trial?
COURAGE-2, a Cuban open-label phase 3 trial published in 2026, gave 95 acute stroke patients intravenous EGF 75 micrograms plus GHRP-6 5 mg twice daily for seven days against standard care in 93. Disability at three and six months did not differ in the intention-to-treat analysis.
Which species has GHRP-6 been studied in?
Humans, extensively as an endocrine probe; rats and mice for heart protection, kidney injury, wound healing and appetite; rabbits for scarring; dogs in a Cuban safety study; and fish, where a ghrelin analogue was fed in aquaculture research. Its antagonist, [D-Lys3]-GHRP-6, appears in many more papers and is a different compound.
Sources
Full citations. Every claim above links to one of these by its id.
- 1
- 2EGF and GHRP6 Co-Administration Attenuates Cognitive Decline in Preclinical Models: Behavioral and Molecular Evidences.
pmid-42399524· · peer-reviewed - 3
- 4
- 5
- 6Growth hormone-releasing peptide 6 (GHRP-6) hydrogel for acute kidney injury therapy via metabolic regulation.
pmid-41327290· · peer-reviewed - 7
- 8
- 9
- 10Subchronic safety assessment of CIGB-500 in beagle dog after repeated daily dose administration over 28 days.
pmid-40024561· · peer-reviewed - 11Intranasal Delivery of a Ghrelin Mimetic Engages the Brain Ghrelin Signaling System in Mice.
pmid-39813130· · peer-reviewed - 12Changes in Locomotor Activity Observed During Acute Nicotine Withdrawal Can Be Attenuated by Ghrelin and GHRP-6 in Rats.
pmid-39857727· · peer-reviewed
Show the remaining 36 sources
- 13Targeting CD36 With EP 80317 Reduces Remote Inflammatory Response to Hind Limb Ischemia-Reperfusion in Mice.
pmid-39552437· · peer-reviewed - 14
- 15
- 16
- 17Calorie restriction activates a gastric Notch-FOXO1 pathway to expand ghrelin cells.
pmid-38958606· · peer-reviewed - 18
- 19
- 20Ghrelin Amplifies the Nicotine-Induced Release of Dopamine in the Bed Nucleus of Stria Terminalis (BNST).
pmid-37760897· · peer-reviewed - 21Efficient transdermal delivery of functional protein cargoes by a hydrophobic peptide MTD 1067.
pmid-35760980· · peer-reviewed - 22
- 23
- 24Growth hormone-releasing peptide 6 prevents cutaneous hypertrophic scarring: early mechanistic data from a proteome study.
pmid-29464859· · peer-reviewed - 25
- 26
- 27Growth Hormone-Releasing Peptide 6 Enhances the Healing Process and Improves the Esthetic Outcome of the Wounds.
pmid-27200188· · peer-reviewed - 28
- 29Insulinotropic action of bombesin-like peptides mediated by gastrin-releasing peptide receptors in steers.
pmid-26812312· · peer-reviewed - 30Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers.
pmid-23099431· · peer-reviewed - 31Gastric mucosal damage in water immersion stress: mechanism and prevention with GHRP-6.
pmid-22791951· · peer-reviewed - 32Interaction between PEO-PPO-PEO copolymers and a hexapeptide in aqueous solutions.
pmid-22185212· · peer-reviewed - 33
- 34
- 35Diagnosis of adult GH deficiency.
pmid-17766155· · peer-reviewed - 36Growth hormone response to GHRH + GHRP-6 in type 2 diabetes during euglycemic and hyperglycemic clamp.
pmid-14693411· · peer-reviewed - 37Growth hormone secretagogue receptor family members and ligands.
pmid-11322507· · peer-reviewed - 38Neuroregulation of growth hormone secretion in domestic animals.
pmid-11311846· · peer-reviewed - 39GH-releasing hormone and GH-releasing peptide-6 for diagnostic testing in GH-deficient adults.
pmid-11030292· · peer-reviewed - 40Acute dexamethasone administration enhances GH responsiveness to GH releasing peptide-6 (GHRP-6) in man.
pmid-10583306· · peer-reviewed - 41
- 42Growth hormone in obesity.
pmid-10193871· · peer-reviewed - 43Growth hormone-releasing peptides.
pmid-9186261· · peer-reviewed - 44
- 45
- 46
- 47
- 48Growth hormone response in man to L-692,429, a novel nonpeptide mimic of growth hormone-releasing peptide-6.
pmid-8077339· · peer-reviewed
Reference card
- Compound
- GHRP-6, ghrelin mimetics
- Evidence tier
- Human clinical trial
- Indexed publications
- 738 · 22 RCTs · 41 other clinical trials
- Approval
- no registered development programme found
- Routes reported
- intranasal, intravenous, oral, subcutaneous
- Reviewed
- Adam Mirando, PharmD,
Study figures are as published in each source and are not recommendations. Print or save this card with its date.
Last reviewed and what changed
Newest first. These are the record's own revision dates, and the same dates feed the sitemap.
- · Reviewed by Adam Mirando, PharmD, on 2026-09-25.
- · Written under the sequencing rule after research/intents/ghrp-6.json: guide (8 sections incl. a twelve-study table), FAQ to 12 plus 5 from the map, dose, weight-normalized, timeline and adverse-event claims from the abstracts, mechanism (ghrelin mimic that found ghrelin), reported-use, regulatory; a cattle study of the antagonist [D-Lys3]-GHRP-6 removed from the evidence table and all claims; misdrafted interactions removed; intent-driven H1 and title.
- · Claims drafted extractively from 48 ledger sources by scripts/draft_claims.py: 38 claims, 25 evidence-table rows. Status researched -> draft.
- · Claims drafted extractively from 48 ledger sources by scripts/draft_claims.py: 45 claims, 25 evidence-table rows. Status researched -> draft.
- · Claims drafted extractively from 48 ledger sources by scripts/draft_claims.py: 48 claims, 25 evidence-table rows. Status researched -> draft.
- · Evidence fetched from Europe PMC and ChEMBL by scripts/fetch_evidence.py; claims not yet written.