GHRP-6
Also known as Growth hormone releasing peptide 6, SKF-110679, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
GHRP-6 is the original growth hormone releasing peptide, a six amino acid ghrelin receptor agonist that produces a solid growth hormone pulse together with intense hunger and a rise in cortisol and prolactin. People use it when they want appetite as much as growth hormone, usually stacked with a GHRH analog.
Reviewed by the amino101 editorial team. .
Quick start
What people commonly do. Not a prescription.- Typical dose
- 100 to 300 mcg
- How often
- 1 to 3 times daily
- Where
- Subcutaneous, belly or thigh
- Timing
- Empty stomach; before bed for growth hormone, 20 to 30 minutes before a meal for appetite
- Effects timeline
- hunger within 30 minutes of the first dose, deeper sleep 1 to 2 weeks, IGF-1 rise by 4 weeks, weight gain and recovery 4 to 12 weeks
- Storage
- Lyophilized in freezer or fridge away from light; reconstituted in fridge 2 to 8 C, use within 4 weeks
- Cycle length
- 8 to 12 weeks
- Break between
- a few weeks off, recheck IGF-1, prolactin and morning cortisol before the next run
A 5 mg vial in 2 mL gives 2.5 mg per mL, so 100 mcg is 4 units and 300 mcg is 12 units on an insulin syringe.
Overview
GHRP-6 is a synthetic hexapeptide developed by Cyril Bowers in the early 1980s, the first of the growth hormone releasing peptides and the compound that led to the discovery of the ghrelin receptor. It stimulates growth hormone release from the pituitary through that receptor, which was cloned in 1996 using GHRP-6 as the probe, three years before ghrelin itself was identified. It was never developed into an approved drug. Everything sold today is research grade material, and there are no long term human trials of repeated use.
The human data are mostly acute: single dose studies in healthy adults, children with short stature and people with growth hormone deficiency showing reliable growth hormone release by intravenous, subcutaneous, intranasal and oral routes. The same studies record a rise in cortisol and prolactin after each dose. What makes GHRP-6 different from GHRP-2 and ipamorelin is the hunger. It produces a strong, fast wave of appetite within about 20 minutes of injection, which fits with ghrelin physiology and is the main reason people choose it or avoid it.
A separate research thread, mostly from a group in Cuba, has studied GHRP-6 for heart and tissue protection in animals, with pig and rat work showing smaller heart attack damage and faster wound healing. None of this has been tested in people. In the community GHRP-6 is run at 100 to 300 mcg one to three times daily with a GHRH analog, most often by people in a gaining phase who want to eat more. This page is educational and reports what appears in research and community protocols, not a recommendation.
How it works
GHRP-6 is an agonist at the growth hormone secretagogue receptor, GHS-R1a, the same receptor that ghrelin binds. In the pituitary it raises calcium in somatotrophs and releases stored growth hormone; in the hypothalamus it boosts GHRH neurons and suppresses somatostatin, so the pulse is amplified and becomes much larger when a GHRH analog is given at the same time. The ghrelin receptor also sits on hypothalamic appetite neurons, and GHRP-6 activates them strongly, which produces the hunger that defines the compound. It also stimulates the pathways that release ACTH and prolactin, so cortisol and prolactin rise for an hour or two after each dose. The cardioprotective effects reported in animals appear to run partly through the CD36 receptor rather than through growth hormone.
Where the research stands
Growth hormone releaseStrong evidence
- Dose dependent GH pulse. Decades of acute human studies show reliable growth hormone release by several routes.
- Synergy with GHRH analogs. Human data show the GHRP plus GHRH combination releases more than the sum of either alone.
Appetite and weight gainModerate evidence
- Increased food intake. The hunger effect is consistent in human dosing studies and in community use; it is the main practical reason people choose GHRP-6.
- Cachexia and underweight. Mechanistically plausible through the ghrelin receptor, but no clinical trial has tested GHRP-6 for this.
Heart and tissue protectionEmerging
- Cardioprotection. Pig and rat studies show reduced infarct size and better function after induced heart attack; no human trial.
- Wound healing. Rodent and pig wound models from the same research group show faster closure; purely preclinical.
Body composition and recoveryEmerging
- Lean mass and recovery. No human outcome trials; expectations rest on growth hormone physiology and on the extra calories people eat on it.
- human pilotGHRP-6 released growth hormone in a dose dependent way in rats and in humans in the original characterization studies, establishing the GHRP class.
- in vitroThe ghrelin receptor GHS-R1a was cloned from pituitary and hypothalamus using GHRP-6 as the ligand, before ghrelin itself was discovered.
- human RCTCombined GHRP-6 and GHRH in healthy adults produced a growth hormone peak far larger than either alone, the basis for the standard GHRP plus GHRH stack.
- rodentGHRP-6 given around the time of coronary occlusion in pigs reduced infarct size and preserved heart function.
- human RCTAcute dosing studies in humans consistently show a rise in cortisol, ACTH and prolactin alongside growth hormone, and a marked increase in hunger.
Rodent and in vitro mean no human data for that finding. Human pilot means small, often uncontrolled. Human RCT means randomized and controlled. Clinical means an approved drug with regulatory data.
Levels over time
Modeled from the half-life. Illustrative, not measured.A half-life of 45 min against dosing every 24 h means each dose has cleared before the next. Nothing stacks; you start from zero every time, and the tissue effect is what carries over.
The hunger arrives before the growth hormone peak and fades as the peptide clears, usually within 1 to 2 hours. The short pulse suits one to three doses a day and pairs well with a short acting GHRH analog.
GHRP-6 dosage and protocols
Runs of 8 to 12 weeks with no loading phase are typical, followed by a few weeks off. Because every dose raises cortisol and prolactin, many people keep GHRP-6 to one or two doses a day and use ipamorelin for the rest. Bloodwork for IGF-1, prolactin and morning cortisol at the end of a run is sensible.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Stacked with a GHRH analog | 100 mcg | once daily before bed, with 100 mcg CJC-1295 no DAC | Subcutaneous, same syringe |
| Appetite before meals | 100 to 200 mcg | 2 to 3 times daily, 20 to 30 minutes before meals | Subcutaneous |
| Solo nightly dose | 200 to 300 mcg | once daily before bed | Subcutaneous |
| Three pulse protocol | 100 mcg | 3 times daily, on waking, after training, before bed | Subcutaneous |
Fasted dosing matters for the growth hormone pulse, so a gap of 20 to 30 minutes between injection and food is standard. The trick with GHRP-6 is that the hunger makes the wait hard, so people who use it for appetite time the dose so the meal lands as the hunger peaks. Bedtime doses line up with the natural nighttime surge. When stacked with a GHRH analog, both go in one syringe.
100 mcg is close to the saturating dose for growth hormone release. Higher doses add mostly hunger, cortisol and prolactin rather than more growth hormone.
Dose calculator
U-100 insulin syringeUnits are a volume on the syringe, not an amount of peptide. Concentration changes every time you change the water volume. The standalone calculator explains the math.
| Vial | Suggested water | Concentration | Low dose draw |
|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 4 units |
| 10 mg | 3 mL | 3.333 mg/mL | 3 units |
How to reconstitute GHRP-6
- 1
Wash your hands and wipe the work surface. Swab both vial stoppers with alcohol and let them dry.
- 2
Pick the water volume with the calculator above and write it on the vial. The concentration means nothing without it.
- 3
Draw the bacteriostatic water into a mixing syringe.
- 4
Insert at an angle and let the water run down the inside wall. Never squirt it straight onto the powder.
- 5
Swirl gently or leave it to dissolve. Do not shake.
- 6
Label with the date and water volume. Store in the fridge at 2 to 8 C and use within about 4 weeks.
- 7
Unmixed vials keep for months in the fridge and longer in the freezer, sealed and out of light.
- Full walkthrough with syringe reading and site rotation: reconstitution guide.
- ✓White, fluffy cake
Lyophilized powder should look like a small white puck or fluffy cake at the bottom of the vial. That is a proper freeze-dry.
- ✓Clear after mixing
Once dissolved the solution should be water-clear with nothing floating in it.
- !Slight clumping
Small clumps that dissolve with gentle swirling are fine. Shipping compacts powder.
- ✕Collapsed or melted
Powder stuck to the sides, glassy, or shrunken means it got hot in transit. Contact the vendor.
- ✕Cloudy or particles
Persistent cloudiness or visible particles after mixing means degraded or contaminated product. Do not use it.
- Week 1 to 2
Strong hunger 15 to 30 minutes after every dose, some flushing or lightheadedness, deeper sleep from bedtime doses.
- Week 2 to 6
Weight goes up if the hunger is fed, recovery feels quicker, water retention at higher doses; IGF-1 measurably higher by week 4.
- Week 6 to 12
Gradual gains in the people who train and eat for them; cortisol and prolactin related complaints surface here in the people prone to them.
Interactions and stacking
CJC-1295 (no DAC)synergistic
The standard pairing; GHRH receptor plus ghrelin receptor produces a pulse several times larger than either alone.
Tesamorelinsynergistic
Same two pathway synergy with the GHRH analog that has the strongest human evidence.
Ipamorelincompatible
Same receptor, so they are alternated rather than combined.
HGHcaution
Exogenous growth hormone suppresses the pituitary, leaving little for a secretagogue to release.
Semaglutide and other GLP-1 drugscaution
The two work in opposite directions on appetite; GHRP-6 undermines the point of a GLP-1 protocol.
Insulin and diabetes medicationscaution
Growth hormone and cortisol both raise glucose for hours after a dose; monitor if you take anything that lowers blood sugar.
Food and sugary drinks before the doseavoid
Insulin and free fatty acids after a meal cut the pulse substantially; eat after the dose, not before.
The standard pairing. The GHRH analog and the ghrelin agonist act on different receptors and the combined pulse is several times larger than either alone.
Same two pathway synergy using the GHRH analog with the strongest human evidence.
Alternated rather than combined: GHRP-6 before meals when hunger is wanted, ipamorelin at bedtime when it is not.
Safety
- ▲Intense hunger shortly after a dose
- ▲Flushing, headache or lightheadedness in the first hour
- ▲Water retention and puffy hands at higher doses
- ▲Tingling in the fingers when stacked heavily
- ▲Raised cortisol, felt by some as restlessness or poorer sleep from daytime doses
- ▲Raised prolactin, which can show as reduced libido or breast tenderness over longer runs
- ▲The hunger is intense and arrives fast. On a fat loss protocol it is the wrong GHRP.
- ▲Raises cortisol and prolactin after every dose, which can affect sleep, mood, libido and breast tissue over longer runs.
- ▲Prohibited in sport by WADA under S2 as a growth hormone releasing peptide.
- ▲Growth hormone pulses raise blood glucose for several hours; people with insulin resistance should watch bloodwork.
- ▲Avoid raising growth hormone and IGF-1 with any active or prior hormone sensitive cancer.
- ▲No long term human safety data exist; the acute studies used single doses in clinics.
- ■Breast tenderness or nipple changes, which point to prolactin
- ■Numbness or carpal tunnel symptoms that persist after lowering the dose
- ■Fasting glucose or HbA1c rising on bloodwork
- ■IGF-1 above the reference range for your age
- ■A new lump, growth or any cancer diagnosis
Community poll
Self-reported by visitors. Not clinical evidence.GHRP-6: frequently asked
What GHRP-6 dosage is commonly reported?
Community protocols report 100 to 300 mcg per injection, one to three times daily, on an empty stomach. Growth hormone release saturates around 100 mcg in most adults, so the higher end mostly buys more hunger and more cortisol. When stacked with a GHRH analog the common pairing is 100 mcg of each.
How strong is the hunger?
Strong. Most people describe a sharp, almost uncomfortable hunger starting 15 to 30 minutes after injection and lasting an hour or so. It is the most reliable effect of the peptide. People who struggle to eat enough use it on purpose before meals; everyone else tends to switch to ipamorelin.
GHRP-6 or GHRP-2 or ipamorelin?
They all release growth hormone through the same receptor. GHRP-6 gives the most hunger, GHRP-2 a somewhat bigger pulse with moderate hunger, and ipamorelin a smaller pulse with almost none of the side effects. Pick by what you want from the side effect profile, since the growth hormone output at 100 mcg is in the same range for all three.
Does GHRP-6 help with injury or heart health?
Pig and rat studies, largely from one Cuban research group, show smaller heart attack damage and faster wound healing with GHRP-6. None of that work has been repeated in people, and nobody should use a research peptide for a heart condition on the strength of animal data.
References
- 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
- A receptor in pituitary and hypothalamus that functions in growth hormone release. Science, 1996
- Growth hormone releasing peptide 6 (GHRP-6) reduces myocardial infarct size and improves cardiac function in a porcine model. Clinical Science, 2007
- Growth hormone (GH)-releasing peptide stimulation of GH release from human somatotroph adenoma cells and the pituitary in healthy adults. Journal of Clinical Endocrinology and Metabolism, 1990