A reliable growth hormone trigger
In healthy men, GHRP-6 given into a vein produced a strong, dose-related growth hormone rise. A 1997 review says the response stays marked in people in their sixties.4
Peptide Guide · Growth hormone and muscle
GHRP-6
Growth hormone-releasing peptide-6
GHRP-6 was the growth hormone-releasing peptide that put the family on the map. It worked for 15 years before anyone found the natural hormone it copies.
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- Studied for
- Growth hormone release and ghrelin receptor biology
- Evidence
- Early human data
- Taken as
- As prescribed by a clinician
GHRP-6, in short
GHRP-6 is a synthetic six-amino-acid peptide, first described in 1984, that activates the ghrelin receptor (GHS-R1a) and prompts the pituitary to release a pulse of growth hormone. It was the first of its kind studied extensively in people, and it led researchers to the receptor and to ghrelin itself. Animal research also covers heart-cell protection. Human data come from short studies.
Medically reviewed by Robert Lufkin, MD (opens in a new tab)
Chief Medical Officer, Vitals Vault · Updated · 17 sources
Before you consider GHRP-6
How does GHRP-6 work?
GHRP-6 copies a hunger hormone to tell the body to release growth hormone.
Mimics a hunger hormone
It acts like ghrelin, a hunger hormone. The pituitary reads it as a cue to release growth hormone.23
Adds to the body’s own cue
Reviews say it adds to the body’s own releasing hormone and eases somatostatin, the brake on growth hormone.4
Fades with nonstop use
The response partly fades with continuous infusion, less with on-off use. A review says long use still raised IGF-1.4
GHRP-6 benefits: what it is studied for
GHRP-6 has no approved use and no large human trial for a health outcome. The evidence is short human experiments and early animal work.
- Human study01
- Animal study02
Early growth in animals
In the first animal work, young rats given the peptide repeatedly over 9 to 25 days gained more weight than controls, and their pituitaries stayed responsive.1
- Human study03
Sleep architecture research
In a small sleep-lab study, GHRP-6 increased stage 2 non-REM sleep, unlike ghrelin and GHRH, which promote slow-wave sleep. This is a research observation, not a sleep treatment.14
What the research shows
Early human data- 1 · Cells in a lab Studied
Alone, GHRP can release growth hormone from pituitary cells in a dish.17
Shows a mechanism
- 2 · Animals Studied
In pigs, it cut dead heart muscle by 78 percent after a blocked artery. In young rats, it raised weight gain.121
Shows an effect in a body
- 3 · People Studied
Short studies in healthy men show a strong, dose-related growth hormone rise. No controlled trial shows benefits for muscle, recovery or aging.64
Shows it works in people
The full guide to GHRP-6
How GHRP-6 began: a molecule that worked before anyone knew why
In 1984, Cyril Bowers and his colleagues published a molecule that had no obvious reason to work as well as it did. It was a synthetic chain of six amino acids, two of them in the mirror-image form that human proteins almost never use. Injected into a vein in rats, it started growth hormone rising within two minutes, peaked at 10 to 20 minutes, and was usually back to baseline within two hours.
It worked in rats, monkeys, lambs and calves, and under special conditions in chicks, so it did not depend on species. It acted directly on the pituitary, and in those animal experiments it released growth hormone without moving LH, FSH, TSH or prolactin. Young rats given it repeatedly over 9 to 25 days gained more weight than controls, and their pituitaries stayed fully responsive.
The puzzle was what it did not resemble. GHRP-6 shares no structure with GHRH, the body’s known growth hormone releaser, and it seemed to act through a receptor of its own. Comparing the two between 1982 and 1984, Bowers concluded that GHRP-6 was probably imitating a natural hormone nobody had found yet. Proving him right took another 15 years.
That thread runs through this whole page. As a drug, GHRP-6 has a thin clinical record. As a research tool, it helped open a whole branch of endocrinology, from a hunger hormone in the stomach to the oral compound MK-677.1473
The drug that found its own hormone
Medicine usually runs from biology to drugs. Someone discovers a hormone, then its receptor, and chemists design a molecule to fit. GHRP-6 ran the story backwards. The synthetic key came first, and researchers followed it to the lock, and then to the natural key.
A key human result came in 1990. Bowers and colleagues gave GHRP-6 to 18 healthy men and saw a strong, dose-related growth hormone release. When small amounts of GHRP-6 and GHRH were given together, the two released far more than either one alone. That kind of synergy suggests two independent systems, and the authors wrote that GHRP-6 likely reflected a new physiological system still waiting to be characterized.
Then the drug hunters joined in. Merck chemists looking for something that could be swallowed found a non-peptide molecule in 1993 that behaved as a mimic of GHRP-6. By 1995 they had MK-0677, an oral compound they described as mechanistically indistinguishable from GHRP-6. In 1996 a Merck team cloned the receptor these compounds act on, in the pituitary and hypothalamus, and noted that the drugs appeared to mimic a hormone not yet discovered.
In 1999, Kojima, Kangawa and colleagues in Osaka purified that hormone from rat stomach. It was a 28-amino-acid peptide carrying a fatty acid chain that it needs in order to work, and they named it ghrelin, from an ancient root meaning to grow. Bowers later summed up the arc in one line: the unnatural peptide gave rise to the natural one.
This is why GHRP-6 still matters, even to people who will never take it. It helped set the research path that produced GHRP-2, hexarelin and the oral MK-677. When someone describes MK-677 as acting like a peptide, this is the peptide they mean.6892374
How GHRP-6 works on the pituitary and hypothalamus
GHRP-6 binds the growth hormone secretagogue receptor, GHS-R1a, on pituitary cells and in the hypothalamus. The pituitary reads it as a ghrelin signal and releases growth hormone. Bowers found that GHRPs increase pulsatile growth hormone release in children and in younger and older adults, and that in living people this depends on the body’s own GHRH, even though GHRP alone can release growth hormone from pituitary cells in a dish.
The other half of the picture is somatostatin, the brake on growth hormone. In the original 1984 work, somatostatin blocked the GHRP-6 response, and a 1997 review favors the idea that GHRPs act partly by counteracting somatostatin at the pituitary and the hypothalamus. Opioid blockers such as naloxone did not change the effect.
The response is harder to switch off than GHRH’s. Glucose, free fatty acids, glucocorticoids, growth hormone itself and extra somatostatin blunt the GHRP response, but the review notes that these same influences almost abolish the response to GHRH. That resilience is one reason the review saw a possible clinical role for GHRPs in some states of low growth hormone.
Repeated exposure changes things. The growth hormone response is reproducible but partly desensitizes, more during a continuous infusion and less with intermittent dosing. Even so, the review reports that prolonged GHRP use raised IGF-1, the liver-made hormone that carries much of growth hormone’s effect, in both animals and people, without singling out which findings came from GHRP-6.2714
GHRP-6 in people: what the human studies measured
The 1990 study set the template. In 18 healthy men, GHRP-6 produced a dose-related growth hormone rise, with the average peak at the highest dose tested more than 50 times the placebo level. The researchers saw no adverse clinical effects or lab abnormalities from GHRP-6. Prolactin and cortisol roughly doubled, but only at that highest dose, and LH and TSH did not change in the first hour.
Later work broadened the picture for the family as a whole. A 1997 review reports a marked growth hormone response to GHRPs after intravenous, under-the-skin, nasal and even oral dosing. The response does not depend on sex, rises from birth to puberty, holds through adulthood and declines afterwards. By the sixth decade it is reduced but still marked, and still larger than the response to GHRH.
A close look at how the body handles GHRP-6 came from Havana in 2013. Nine healthy men received a single intravenous dose, and the peptide cleared in two phases, a fast distribution phase of about 8 minutes and an elimination half-life of about 2.5 hours. In four of the nine men, the researchers saw unexpected spikes in blood levels during the elimination phase, which the paper reports without explaining.6411
GHRP-6 benefits studied beyond growth hormone: protecting heart cells
A Cuban research group has spent years testing GHRP-6 as a protector of damaged tissue. In a 2007 study, pigs had a major heart artery blocked for an hour and then reopened, a model of a heart attack followed by restored blood flow. Compared with saline, GHRP-6 cut the mass of dead heart muscle by 78 percent and its thickness by half, and more than half of the treated pigs showed none of the abnormal ECG waves that mark a completed infarct.
Blood markers of heart damage and inflammation were lower too, and measures of oxidative stress suggested GHRP-6 protected cells by limiting reactive oxygen species and preserving antioxidant defenses. It did not change deaths during surgery from heart rhythm problems. GHRP-6 did not push heart IGF-1 gene activity beyond the rise the blocked artery had already caused, though that alone cannot say whether growth hormone or IGF-1 played a part in the protection.
The same group’s 2017 review offers one possible explanation for the family. GHRPs bind two different receptors, the ghrelin receptor and a second receptor called CD36. Binding CD36 switches on survival pathways inside cells, and the review describes protective effects in heart, nerve, gut and liver cells, along with reduced inflammation and scarring in animal models.
Two cautions belong next to those numbers. Much of this work comes from one research group, and it is animal and cell research. The review itself concludes that GHRPs still await a definitive clinical niche, with protection against reperfusion damage, the injury that can follow restored blood flow, as the most promising candidate.1213
Appetite, sleep and the other jobs of the ghrelin receptor
Ghrelin is best known as a hunger hormone, and the GHRP family inherited that job. Bowers wrote that the first sign these peptides did more than release growth hormone was an increase in food intake. Some GHRPs raise appetite, which can complicate a body-composition goal.
Sleep is where the family members part ways. Ghrelin and GHRH both promote slow-wave sleep, the deepest stage. GHRP-6, in a sleep-lab study cited by Munich researchers, increased stage 2 sleep instead, the lighter non-REM stage. Its relative hexarelin went further and reduced deep sleep while raising cortisol overnight.
Why molecules sharing a receptor would push sleep in different directions is still open. The Munich group’s hypothesis for hexarelin is that it tips the balance between GHRH and CRH, the stress-axis starter, toward CRH. That matters because the largest natural growth hormone pulse of the day comes in early deep sleep, and hexarelin thinned deep sleep while raising overnight growth hormone. The study did not show whether one pulse simply replaced another.7314
What we actually know about GHRP-6 in people
GHRP-6 has a long history in human research and a short list of human outcomes. People have received it in pharmacology studies measuring growth hormone, prolactin and cortisol, in pharmacokinetic work, and in sleep-lab experiments. Those studies show it reliably raises growth hormone across ages and routes.
The studies cited here do not show that GHRP-6 improves muscle, strength, recovery, heart outcomes or ageing in people. The heart-protection results come from animals, and the earliest weight-gain results came from young rats.
That leaves GHRP-6 in an unusual position. Scientifically it may be one of the most important peptides on this site, because of what it led to. Clinically it remains a research compound. Human work has measured hormone responses, blood levels and sleep, but the cited evidence does not establish a meaningful clinical benefit.6411131
GHRP-6 side effects and safety
In the 1990 human study, GHRP-6 caused no adverse clinical effects or lab abnormalities, though prolactin and cortisol rose at the highest dose. That difference from the original animal work, where prolactin did not move, is a reminder that species and dose both change the picture. Its close relatives GHRP-2 and hexarelin raise prolactin, ACTH and cortisol in people, so the class is not fully specific to growth hormone.
FDA’s April 2026 compounding page says it found limited safety information for GHRP-6, but that the available data reveal concerns including a potential effect on cortisol and higher blood glucose from reduced insulin sensitivity. It also notes a risk of immune reactions for some routes, linked to peptide aggregation and impurities.
The glucose concern fits what growth hormone does, since it makes tissues less responsive to insulin. Anyone with diabetes or prediabetes, a personal history of cancer, a cortisol-related condition, a pregnancy or a place in tested sport should take GHRP-6 to a clinician as a question first.61515
Which labs matter with GHRP-6, and why
No validated GHRP-6 monitoring panel exists. As general baseline context, fasting glucose, fasting insulin and HbA1c describe glucose handling, which a clinician may want to see because FDA names higher blood glucose from reduced insulin sensitivity as a GHRP-6 concern. HbA1c shows the three-month average behind any single reading.
Cortisol is the other marker people ask about. FDA flags a potential cortisol effect, and in the 1990 human study cortisol roughly doubled at the highest dose. A single morning value needs clinical context; it does not measure stress or overall stress-axis function on its own.
This is how Vitals Vault approaches anything in the growth hormone family. A blood panel at Quest Diagnostics comes first, a licensed clinician reviews your results and history and decides what, if anything, fits, and any course ends with a retest of the same markers.1546
Where GHRP-6 stands in 2026
GHRP-6 is not an FDA-approved drug. FDA’s April 2026 compounding page lists it among bulk substances that may present significant safety risks for 503B outsourcing facilities. The enforcement discretion FDA granted on October 29, 2026 covers six other peptides for 503A compounding, and GHRP-6 is not one of them.
In sport, growth hormone secretagogues and releasing factors fall in the S2 class of the World Anti-Doping Agency’s Prohibited List, which applies in and out of competition.
Products sold online as research chemicals are not made for people and fall outside both policies.151617
What this means for you
GHRP-6 is the original ghrelin mimic. It reliably releases growth hormone, it helped lead scientists to the ghrelin receptor and to ghrelin itself, and in a pig study it reduced heart damage, with a second receptor, CD36, proposed as one route for the family. Its human record is short pharmacology studies, and FDA has flagged cortisol and blood sugar concerns.
Knowing its history changes how you read the rest of the growth hormone family. Several newer compounds act on the same receptor, but their effects on hunger, cortisol and insulin differ and need compound-specific evidence. Before choosing among them, the question worth asking is how your own blood sugar, sleep and stress axis would absorb a push on that receptor.71315
What to expect with GHRP-6
A responsible start is a health history, a baseline blood panel and a clinician’s view on whether anything in the growth hormone family fits. GHRP-6 is not part of the October 2026 compounding pathway, so for most people that conversation is about the trade-offs and the alternatives.
On timing, the studies describe a fast effect. Growth hormone began rising within minutes in animals and the peptide’s elimination half-life in people was about 2.5 hours. With continuous use the response partly fades. No human study has tracked body composition, recovery or heart outcomes over months, so any longer timeline is unknown.111416
Key GHRP-6 studies
Bowers et al., 19841
Lab and animal study · Rats, monkeys, lambs, calves and chicks
Growth hormone rose within 2 minutes; extra weight gain in young rats over 9 to 25 days of repeated administration
Limits: Animals only
Bowers et al., 19906
Dose-response study · 18 healthy men
Strong, dose-related growth hormone release and synergy with GHRH; no adverse clinical effects
Limits: Single doses; prolactin and cortisol rose at the top dose
Berlanga et al., 200712
Randomized animal study · Pigs with a 1-hour heart artery blockage
Dead heart muscle mass cut by 78 percent versus saline
Limits: Pigs, one research group
Cabrales et al., 201311
Pharmacokinetic study · 9 healthy men
Elimination half-life about 2.5 hours; unexplained level spikes in 4 of 9
Limits: Single intravenous doses, small group
Berlanga-Acosta et al., 201713
Historical review · Animal, cell and human studies since 1980
GHRPs bind both the ghrelin receptor and CD36 and protect cells in several organs
Limits: Written by the main research group; awaits a clinical use
GHRP-6 myths and evidence
GHRP-6 was designed to copy ghrelin
It came first. GHRP-6 was described in 1984, its receptor was cloned in 1996, and ghrelin was discovered in 1999. Researchers followed the synthetic peptide to the natural hormone.123
GHRP-6 only affects growth hormone
In healthy men, prolactin and cortisol roughly doubled at the highest dose tested, and FDA names potential cortisol and blood glucose effects. The ghrelin receptor also drives appetite.6157
GHRP-6 has been shown to heal hearts
The heart-protection results come from pigs and cell studies. The research group’s own 2017 review says GHRPs still await a definitive clinical use.1213
GHRP-6 is gone from the blood in minutes
In nine healthy men it cleared in two phases, a quick distribution phase of about 8 minutes and an elimination half-life of about 2.5 hours.11
How is GHRP-6 taken?
GHRP-6 dosage
There is no FDA-approved dose of GHRP-6 for any use. Human studies gave healthy men injections into a vein: single weight-based doses to measure growth hormone release or how quickly the body clears the drug, and, in one placebo-controlled sleep study, four fixed injections across a single night. The dosage table lists them. None tested use over days or weeks or at home, and your clinician sets your dose.611
Typical GHRP-6 dosage
GHRP-6 has no FDA-approved dose. The human doses listed here are injections into a vein in healthy men: single weight-based doses, from small doses that tested growth hormone release to larger doses in a study of drug levels, plus four fixed injections across one night in a sleep study. None tested use over days or weeks or at home, and a clinician sets the actual dose.
Already have a prescribed dose? The peptide dosage calculator turns it into the units to draw on an insulin syringe.
Human trial · Injection into a vein
0.1, 0.3 or 1.0 µg/kg
Single dose6
Healthy men; prolactin and cortisol rose only at the highest dose
Human trial · Injection into a vein
100, 200 or 400 µg/kg
Single dose11
Nine healthy men in a study of how the body clears the drug
Human trial · Injection into a vein
50 µg per injection
Four injections across one night10
Healthy men in a placebo-controlled sleep study; growth hormone, ACTH and cortisol rose
Is GHRP-6 right for you?
A clinician makes the call. These are the questions they will ask first.
It may suit
- Adults curious about growth hormone biology who want a clinician to review their labs first
- People who want to compare GHRP-6, GHRP-2 and newer secretagogues before deciding anything
- Anyone who wants glucose and insulin measured before and after, not guessed
Talk to a clinician first if you are
- Diabetes, prediabetes or insulin resistance, or taking diabetes medicine
- A personal or family history of cancer (growth hormone and IGF-1 promote cell growth)
- Pregnant or breastfeeding
- Cortisol-related conditions such as Cushing’s syndrome or adrenal disease
- Tested athletes (WADA prohibits growth hormone secretagogues)
Vitals Vault peptide care starts with a blood panel and a licensed clinician, and ends with a retest.
Get early access to peptide careGHRP-6 vs GHRP-2
| Attribute | GHRP-6 | GHRP-2 |
|---|---|---|
| Relationship | The original hexapeptide | Synthetic analog of GHRP-6 |
| Target | Ghrelin receptor | Ghrelin receptor |
| FDA safety flags | Cortisol, higher blood glucose | Increased insulin requirement, pancreatitis reports |
| On FDA’s safety page | Yes, 503B | Yes, injectable and nasal, 503B |
A ghrelin signal touches glucose and cortisol as well as growth hormone
A push on growth hormone also lands on blood sugar and cortisol. FDA’s page names a potential effect on cortisol and a rise in blood glucose from lower insulin sensitivity for GHRP-6.
The practical question is how well your own metabolism absorbs a push like that. Fasting glucose, insulin and HbA1c show it, and sleep, training and diet shape the same system without any injection.154
What else moves the same system
- 01Deep sleepThe largest natural growth hormone pulse tends to arrive in early deep sleep.
- 02Resistance trainingHeavy lifting is a strong natural trigger for growth hormone release.
- 03Insulin sensitivityFDA ties GHRP-6 to higher blood glucose from lower insulin sensitivity, so fasting insulin and glucose are worth knowing.
- 04Know your cortisolFDA names a potential effect on cortisol, and a morning value shows your baseline.
Labs to check with GHRP-6
A blood test before you start and a retest after shows what actually changed for you. It is how Vitals Vault approaches every treatment.
- TestA baseline panel at Quest Diagnostics.
- DecideA licensed clinician reviews your history and results.
- RetestThe same markers again, side by side.
- Fasting glucoseA simple metabolic marker to retest.
- Fasting insulinShows insulin resistance earlier than glucose alone.
- HbA1cYour average blood sugar over about three months.
- CortisolFDA flags a cortisol effect, so a clinician may want a baseline for context. One value does not measure stress on its own.
Is GHRP-6 FDA approved?
No. GHRP-6 is not an FDA-approved drug. FDA’s compounding safety page lists it for 503B outsourcing facilities, and the October 29, 2026 enforcement discretion covers six other peptides that do not include GHRP-6.1516
GHRP-6 timeline
1984
Bowers and colleagues describe GHRP-6 and show it releases growth hormone in animals.1
1990
In 18 healthy men, GHRP-6 releases growth hormone and acts synergistically with GHRH, pointing to a separate, undiscovered system.6
1995
Merck describes MK-0677, an oral non-peptide compound that acts like GHRP-6.9
1996
A Merck team clones the pituitary and hypothalamic receptor GHRPs act on.2
1997
A review describes GHRP-6 as the first hexapeptide extensively studied in people.4
1999
Kojima and colleagues identify ghrelin as the natural ligand of that receptor.3
April 2026
FDA’s compounding safety page lists GHRP-6, citing a potential effect on cortisol and higher blood glucose.15
GHRP-6 questions
What is GHRP-6 used for?
GHRP-6 is studied as a growth hormone releasing peptide and as a research tool for ghrelin receptor biology. People ask about it for muscle, recovery and ageing, but no controlled trials show those benefits. It is not FDA-approved for any use.
What are the benefits of GHRP-6?
The documented effect is a marked, dose-related rise in growth hormone. Early animal work also showed extra weight gain in young rats. Benefits for muscle, fat loss or ageing in people have not been shown in controlled trials.
How does GHRP-6 work?
It activates the ghrelin receptor on the pituitary and in the hypothalamus, which prompts growth hormone release. It adds to the effect of GHRH and works partly by counteracting somatostatin.
What are the side effects of GHRP-6?
FDA reports limited safety data but names a potential effect on cortisol and higher blood glucose from decreased insulin sensitivity, plus a risk of immune reactions from impurities and aggregation. Close relatives also raise prolactin and ACTH.
How is GHRP-6 related to ghrelin and MK-677?
GHRP-6 came first. It was made in a lab in the 1980s, its receptor was cloned in 1996, and ghrelin, the natural hormone for that receptor, was found in the stomach in 1999. Merck’s oral compound MK-0677 was designed as a mimic and described as acting just like GHRP-6.
What is the GHRP-6 dosage?
There is no FDA-approved dose. Studies gave healthy men injections into a vein: single weight-based doses, or four injections across one night in a sleep study. None tested use over days or at home. Your clinician sets your dose.
GHRP-6 vs GHRP-2: what is the difference?
GHRP-2 is a synthetic analog of GHRP-6. Both act on the ghrelin receptor. FDA names cortisol and glucose effects for GHRP-6, and increased insulin requirement and pancreatitis reports for GHRP-2.
Is GHRP-6 FDA approved?
No. GHRP-6 is not an FDA-approved drug. FDA lists it among bulk substances that may pose significant safety risks for 503B compounding, and it is not among the six peptides covered by the October 2026 enforcement discretion.
Is GHRP-6 banned in sports?
Growth hormone secretagogues and releasing factors fall in the S2 class of the WADA Prohibited List, which applies in and out of competition. Tested athletes should not use GHRP-6.
Can I get GHRP-6 through Vitals Vault?
Vitals Vault is opening clinician-led peptide care that starts with a blood test. Join the peptides waitlist to hear first. A licensed clinician reviews your history and labs and decides what, if anything, is right for you.
Peptides, prescribed and measured
Vitals Vault is opening peptide care that starts with your blood work, is prescribed by licensed US clinicians and ends with a retest. Join the waitlist to hear first.
- Prescription only
- Licensed US clinicians
- Quest Diagnostics labs
Keep reading
Full Peptide Guide- GHRP-2A six-amino-acid ghrelin-receptor agonist that triggers a sharp pulse of growth hormone. Used in Japanese diagnostic research.
- HexarelinA potent six-amino-acid ghrelin-receptor agonist studied for growth hormone release and heart function.
- IpamorelinA five-amino-acid growth hormone secretagogue that mimics ghrelin, studied for its selective release of growth hormone.
- FDA peptide update 2026What FDA’s October 2026 decision on six peptides means for you.
- CJC-1295A long-acting growth hormone releasing hormone analog, studied for raising growth hormone and IGF-1.
Sources
- 1. Bowers CY, et al. On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology. 1984 (opens in a new tab)
- 2. Howard AD, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996 (opens in a new tab)
- 3. Kojima M, et al. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999 (opens in a new tab)
- 4. Ghigo E, et al. Growth hormone-releasing peptides. Eur J Endocrinol. 1997 (opens in a new tab)
- 5. Arvat E, et al. Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Peptides. 1997 (opens in a new tab)
- 6. Bowers CY, et al. Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. J Clin Endocrinol Metab. 1990 (opens in a new tab)
- 7. Bowers CY, et al. History to the discovery of ghrelin. Methods Enzymol. 2012 (opens in a new tab)
- 8. Smith RG, et al. A nonpeptidyl growth hormone secretagogue. Science. 1993 (opens in a new tab)
- 9. Patchett AA, et al. Design and biological activities of L-163,191 (MK-0677): a potent, orally active growth hormone secretagogue. Proc Natl Acad Sci U S A. 1995 (opens in a new tab)
- 10. Frieboes RM, et al. Growth hormone-releasing peptide-6 stimulates sleep, growth hormone, ACTH and cortisol release in normal man. Neuroendocrinology. 1995 (opens in a new tab)
- 11. Cabrales A, et al. Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers. Eur J Pharm Sci. 2013 (opens in a new tab)
- 12. Berlanga J, et al. Growth-hormone-releasing peptide 6 (GHRP6) prevents oxidant cytotoxicity and reduces myocardial necrosis in a model of acute myocardial infarction. Clin Sci (Lond). 2007 (opens in a new tab)
- 13. Berlanga-Acosta J, et al. Synthetic growth hormone-releasing peptides (GHRPs): a historical appraisal of the evidences supporting their cytoprotective effects. Clin Med Insights Cardiol. 2017 (opens in a new tab)
- 14. Frieboes RM, et al. Hexarelin decreases slow-wave sleep and stimulates the secretion of GH, ACTH, cortisol and prolactin during sleep in healthy volunteers. Psychoneuroendocrinology. 2004 (opens in a new tab)
- 15. FDA. Certain bulk drug substances for use in compounding that may present significant safety risks (current as of April 22, 2026) (opens in a new tab)
- 16. NCPA. FDA grants enforcement discretion for compounding six peptides. October 29, 2026 (opens in a new tab)
- 17. World Anti-Doping Agency. Prohibited List (opens in a new tab)