Important limitations
- Individual claims and source links have not yet completed editorial verification.
- Evidence level, applicable study model, formulation, route and population remain unassigned.
GHRP-6
GHRP-6 is the first of Cyril Bowers' synthetic growth hormone-releasing hexapeptides, a six-amino-acid ghrelin-receptor agonist.
Dosing & scaling, explained
The moderated mass amounts below are retained for comparison. Near-duplicates, mix-dependent volumes and device markings are excluded. This is educational source context, not a protocol or recommendation.
Mass amounts available for comparison
- Lower range100 mcgDose
Recorded example with no verified study backing; shown for amount literacy only.
- Mid range500 mcgDose
Recorded example with no verified study backing; shown for amount literacy only.
Only mcg or mg amounts are retained. The calculator derives mL, syringe units or pen clicks from the current vial strength, water volume and device.
No independently verified schedule
Evidence context
No clinical amount or schedule is inferred from this material. Source verification is pending, and every displayed amount remains educational context rather than guidance.
Storage, handling and interpretation
Product identity
Verify the exact compound, formulation and amount against the product label or certificate before calculation.
Storage & handling
Follow the product label, certificate and validated laboratory SOP; no universal storage assumption is applied here.
Prepared solutions
Label concentration and preparation date, use sterile technique where applicable, and follow a validated stability protocol.
Reported protocols for GHRP-6
What published studies and recent community write-ups report about amounts, timing and course length. 8 clinical, 1 preclinical and 4 community-reported rows, each linked to its source. These are descriptions of what others report, not instructions, and nothing here is medical advice.
| Context | Dose | Frequency | Route | Course | Source |
|---|---|---|---|---|---|
| Clinical8 rows | |||||
| Oral and intravenous dose-finding in men and children5 normal men and 9 short-stature children with varying GH deficiency | 100 and 300 mcg/kg orally; 0.1, 0.3 and 1.0 mcg/kg intravenously for comparison | Single doses | Oral and intravenous bolus | Single-dose sessionsNot applicable | Journal of Clinical Endocrinology and Metabolism (PubMed)1992 |
| Oral 300 mcg/kg raised GH 202-fold over baseline, peaking at 60-75 minutes, and released about the same amount as 1 mcg/kg intravenously, giving an oral activity of roughly 0.3%. Four of nine children responded like the adults, three weakly and two not at all. | |||||
| Intranasal dosing and a 7-dose repeat course in men6 healthy men | 1 mcg/kg intravenous; 5, 15 or 30 mcg/kg intranasal; 15 mcg/kg per dose on repeat | Single doses, then every 8 hours for 7 consecutive doses | Intranasal (and intravenous comparison) | About 2 days of repeat dosingNot applicable | Endocrinologia Japonica (PubMed)1991 |
| The intravenous dose gave a mean GH peak of 55 mcg/L and intranasal doses released GH in proportion to dose (peak 40 mcg/L at 30 mcg/kg). Seven intranasal doses over two days were tolerated, did not blunt the GH response and raised IGF-I from 95 to 126 mcg/L; prolactin and cortisol rose slightly after the intravenous dose. | |||||
| 24-hour infusion in young men8 healthy young men | 1.0 mcg/kg per hour, followed by a 1.0 mcg/kg GHRP or GHRH bolus | Continuous for 24 hours (two separate occasions) | Intravenous infusion | 24 hoursNot applicable | Journal of Clinical Endocrinology and Metabolism (PubMed)1993 |
| GH secretion rose 8-fold and stayed pulsatile, IGF-I rose 12-22% while it fell on saline days, and no significant adverse effects were reported. The infusion blunted the response to a further GHRP bolus but enhanced the response to GHRH, showing the attenuation is receptor-level rather than pituitary depletion. | |||||
| 4-day oral course in elderly women7 healthy women aged 65-82 | 300 mcg/kg per dose | Twice daily | Oral | 4 daysNot applicable | European Journal of Endocrinology (PubMed)1994 |
| Oral GHRP-6 released more GH than a maximal 1 mcg/kg intravenous GHRH dose in these older women, and the response was maintained, if anything larger, after four days of twice-daily dosing. IGF-I did not rise significantly over so short a course. | |||||
| Oral GHRP-6 versus intravenous GHRH in short children13 prepubertal children with normal short stature, aged 6-10 | 300 mcg/kg orally (compared with 1 mcg/kg intravenous GHRH-29) | Single dose, with or without 4 g oral arginine | Oral | Single-dose sessionsNot applicable | European Journal of Endocrinology (PubMed)1995 |
| The GH response to oral GHRP-6 (peak about 19 mcg/L at 60-75 minutes) matched that of the maximal intravenous GHRH dose, and oral arginine did not add to it. This is acute test work in children, not treatment. | |||||
| Night-time routes compared for sleep and hormone effectsHealthy young men | 300 mcg/kg oral (enteric-coated capsules at 21:00); 30 mcg/kg intranasal or sublingual at 22:45 | Single dose per night, placebo-controlled | Oral, intranasal or sublingual | Single nightsNot applicable | Journal of Neuroendocrinology (PubMed)1999 |
| Only the intranasal dose significantly raised GH across the night, with a trend to higher ACTH and more stage 2 sleep; the oral capsule left GH, ACTH and cortisol unchanged and the sublingual dose produced only a trend. The authors stressed that effects depend on dose, duration and route. | |||||
| Phase 1 single-dose escalation (CIGB-500, Cuba)18 healthy men aged 18-35, 3 per dose level | 1, 10, 50, 100, 200 or 400 mcg/kg | Single dose | Intravenous | Single dose with follow-upNot applicable | Investigaciones Medicoquirurgicas (Medigraphic)2014 |
| All six dose levels were reached; 23 adverse events (6 different types) occurred in 12 of 18 men, none serious, and no harmful oxidative stress was detected. The trial was uncontrolled and single-dose, so it says nothing about repeated use. | |||||
| Human pharmacokinetics after intravenous bolus9 healthy men | 100, 200 or 400 mcg/kg | Single dose | Intravenous bolus | 12 hours of samplingNot applicable | European Journal of Pharmaceutical Sciences (PubMed)2013 |
| GHRP-6 followed a two-compartment profile with a distribution half-life of about 7.6 minutes and an elimination half-life of about 2.5 hours, and exposure rose roughly in proportion to dose. These are intravenous figures; no subcutaneous pharmacokinetics have been published. | |||||
| Preclinical1 row | |||||
| Acute myocardial infarction model (pigs)Female Cuban Creole pigs with 1-hour coronary occlusion and 72-hour reperfusion | 400 mcg/kg | Single dose | Intravenous | 72-hour survival periodNot applicable | Clinical Science (PubMed)2007 |
| GHRP-6 reduced infarct mass by 78% and infarct thickness by 50% against saline, with lower CK-MB and CRP and preserved antioxidant defenses, without changing surgical mortality from arrhythmias. The dose is hundreds of times the GH-releasing dose and the model is a single-dose animal experiment. | |||||
| Community-reported4 rows | |||||
| Three-times-daily ladder (community) | 100 mcg (weeks 1-2), 200 mcg (weeks 3-4), 300 mcg (weeks 5-12) per injection | 3 times daily at least 4 hours apart, morning, midday and bedtime, fasted | Subcutaneous | 12 weeksSeveral weeks to a few months on, then off; no set schedule | Community resource2026 |
| Reviewed July 2026, this guide reconstitutes a 5 mg vial in 3 mL (about 1,667 mcg/mL) and places each dose 2-3 hours after a meal and 30 minutes before eating because fat and carbohydrate blunt the GH pulse. It states that GHRP-6 is not FDA-approved, is prohibited in sport by WADA, and that no controlled human trial validates any schedule for muscle gain or fat loss. | |||||
| Tiered community table | 100 mcg (beginner), 200 mcg (intermediate, most common), 300 mcg (advanced) | 2 times daily (morning and bedtime) to 3 times daily, fasted | Subcutaneous | 8-12 weeks standard; 6-8 weeks shorter; 4-8 weeks for appetite-focused use4 weeks off; optional 5 on/2 off weekly | Community resource2026 |
| Reviewed February 2026, this guide quotes a 15-20 minute plasma half-life, describes saturation of GH release around 200-300 mcg (2-3 mcg/kg) with cortisol, prolactin and hunger rising beyond it, and calls appetite the factor that limits titration. It notes that long-term human safety data are limited. | |||||
| 100 mcg saturation-dose chart with hunger control | 100 mcg (4 units at 2,500 mcg/mL from a 5 mg vial in 2 mL); 200 mcg for bulking | 100 mcg at bedtime in week 1, then 2-3 times daily, fasted | Subcutaneous, lower abdomen or flanks, rotating daily | 8-16 weeks4-8 weeks off | Community resource2026 |
| This 2026 chart treats 100 mcg as near the per-bolus saturation dose, reports hunger within 15-30 minutes and GH release within 5-15 minutes, and allows a 20-30 minute window before eating after each injection. It describes GHRP-6 as sitting between hexarelin and ipamorelin for attenuation with prolonged use. | |||||
| Appetite-focused and general dosing blog | 100-300 mcg; 100-200 mcg about 30 minutes before meals for appetite | 2-3 times daily | Subcutaneous (intramuscular, intranasal, oral and sublingual listed as alternatives) | 8-12 weeks (4-8 weeks for appetite use)4-6 week washout | Community resource2026 |
| Published February 2026 by a peptide-matching site, this guide quotes a 15-20 minute half-life and claims early effects in 2-3 weeks with a peak in weeks 6-10; these timings and its bioavailability percentages are not referenced to any human trial and should be read as marketing-adjacent. | |||||
How a course is commonly described
- Week 1Community-reported
Community charts open with a single 100 mcg bedtime injection on an empty stomach to gauge the hunger response, which sources place 15-30 minutes after the dose. The GH pulse itself is described as arriving within minutes and fading within a few hours.
- Weeks 2-4Community-reported
Dosing expands to two or three fasted injections a day, at 100 mcg in the first two weeks and 200 mcg in weeks 3-4 on the stepped ladder, often paired with a GHRH analog. Guides describe sleep and appetite changes here and nothing measurable in body composition.
- Weeks 5-12Community-reported
The upper tier holds 200-300 mcg three times daily through week 12, the point at which guides say any body-composition change would appear with training and diet. Sources warn that GH response attenuates with continuous ghrelin-receptor stimulation and that cortisol and prolactin rise with dose.
- BreakCommunity-reported
Cycles of 8-16 weeks are followed by 4-8 weeks off, with some users switching to weekday-only dosing instead. The stated rationale is recovery of receptor sensitivity and a check on cortisol and prolactin; no study has examined any off period.
- Clinical comparisonClinical
No human study has run GHRP-6 for more than a few days: the longest exposures are a 24-hour infusion at 1 mcg/kg per hour, seven intranasal doses over two days and four days of twice-daily oral dosing. Even the 24-hour infusion blunted the response to a further GHRP-6 bolus, the attenuation that community cycling tries to avoid.
- Every human GHRP-6 study was acute or lasted days at most, by intravenous, intranasal or oral routes. The 8-16 week subcutaneous courses described by community sources have never been tested, and no subcutaneous pharmacokinetic data exist.
- Measured intravenous half-lives are about 7.6 minutes for distribution and 2.5 hours for elimination; community pages quote 15-20 minutes. Appetite stimulation, prolactin and cortisol release are documented human effects that scale with dose.
- GHRP-6 has no approved therapeutic use and is prohibited in sport as a GH secretagogue according to the community sources above. The Cuban cytoprotection program used single 400 mcg/kg intravenous doses, far above any GH-releasing or community dose. The rows record what sources report, not recommendations.
Sources for this section (13)
- The growth hormone-releasing activity of a synthetic hexapeptide in normal men and short statured children after oral administration
- Intranasal administration of His-D-Trp-Ala-Trp-D-Phe-LysNH2 (growth hormone releasing peptide) increased plasma growth hormone and insulin-like growth factor-I levels in normal men
- Twenty-four-hour growth hormone (GH)-releasing peptide (GHRP) infusion enhances pulsatile GH secretion and specifically attenuates the response to a subsequent GHRP bolus
- Growth hormone-releasing activity of growth hormone-releasing peptide-6 is maintained after short-term oral pretreatment with the hexapeptide in normal aging
- Growth hormone-releasing effect of oral growth hormone-releasing peptide 6 (GHRP-6) administration in children with short stature
- Effects of growth hormone-releasing peptide-6 on the nocturnal secretion of GH, ACTH and cortisol and on the sleep EEG in man: role of routes of administration
- Clinical safety of Growth Hormone-Releasing Peptide 6 (GHRP-6) in healthy volunteers
- Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers
- Growth-hormone-releasing peptide 6 (GHRP6) prevents oxidant cytotoxicity and reduces myocardial necrosis in a model of acute myocardial infarction
Plus 4 community resources (dosing guides, forum threads and vendor write-ups), reported above but not linked.
Overview
GHRP-6 is the first of Cyril Bowers' synthetic growth hormone-releasing hexapeptides, a six-amino-acid ghrelin-receptor agonist whose discovery in the early 1980s led to the identification of ghrelin itself. Human pharmacology studies from 1990 onward showed that 1 mcg/kg intravenously, 15-30 mcg/kg intranasally or about 300 mcg/kg orally releases GH, that a 24-hour infusion raises pulsatile GH and IGF-I, and that it also stimulates appetite, prolactin and cortisol. Cuban researchers later developed it as a cytoprotective drug (CIGB-500), publishing a pig infarct study and a single-dose phase 1 safety and pharmacokinetic program in healthy men. It has no approved therapeutic use anywhere, is prohibited in sport as a GH secretagogue according to the sources below, and the 100-300 mcg subcutaneous schedules in circulation are community conventions rather than trial regimens.
What researchers are exploring
These themes organize the educational information currently available. Individual claims remain under source review and are not treatment claims.
- 1
Research
Scientific studies on GHRP-6 and its various effects
- 2
Cognitive Enhancement
GHRP-6's role in learning, memory, and cognitive function
- 3
Neuroprotective Effects
GHRP-6's ability to protect neurons and brain tissue
- 4
Protection Against Parkinson's Disease
GHRP-6's potential role in Parkinson's disease research
- 5
Skin Improvement and Scar Reduction
GHRP-6's effects on wound healing and scar formation
- 6
Cardiovascular Protection
GHRP-6's protective effects on heart tissue
What is known and what still needs verification
Available context is organized without assigning unsupported study models or evidence grades.
- Not graded
Research
Scientific studies on GHRP-6 and its various effects
- Not graded
Cognitive Enhancement
GHRP-6's role in learning, memory, and cognitive function
Amounts recorded for GHRP-6
These amount records are independent from vial strength, reconstitution volume and measuring device. A recorded source is not the same as study backing, and these values are not recommendations.
- 1Dose · lower endpointSign in for schedule, duration and source context.100 mcg
- 2Dose · upper endpointSign in for schedule, duration and source context.500 mcg
Chemistry identifiers
Sequence, synonyms and registry identifiers as recorded in PubChem, the National Library of Medicine's open chemistry database. Formula, mass and CAS number are summarized at the top of the page.
Sequence
His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Also listed as
GHRP-6, Growth hormone-releasing peptide-6, Growth hormone releasing hexapeptide, SK&F-110679, Hexapeptide-2 (INCI), CIGB-500 (Cuban development code), UNII 4H7N4I6X6A, CHEMBL105462
InChIKey
WZHKXNSOCOQYQX-FUAFALNISA-N
IUPAC name
(2S)-6-amino-2-[[(2R)-2-[[(2S)-2-[[(2S)-2-[[(2R)-2-[[(2S)-2-amino-3-(1H-imidazol-5-yl)propanoyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]propanoyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]-3-phenylpropanoyl]amino]hexanamide
Limitations and unknowns
Sources
1 link carried over from the earlier page, awaiting verification.