MEDICAL DISCLAIMER: Educational research guidelines only. Lyophilized peptides are investigational chemical compounds and are NOT approved for human consumption, diagnosis, or therapy. Consult a licensed physician before any research application.
GHRP-6 Dosage Chart, Schedule & Reconstitution Protocol
Quickstart Highlights
GHRP-6 is a first-generation synthetic hexapeptide growth hormone secretagogue that binds GHSR1a, the ghrelin receptor, a Gq-coupled GPCR expressed on pituitary somatotrophs and hypothalamic NPY/AgRP neurons. Receptor activation triggers phospholipase C, IP3, and PKC signalling to drive growth hormone release while concurrently engaging the central appetite circuitry. Researchers study it for GH amplification with appetite augmentation (useful in cachexia models), for cytoprotective effects on cardiac and gastric tissues independent of GH release, and as the GHRP partner in GHRH+GHRP synergy stacks. It has no FDA approval and is supplied as a research chemical. The peptide produces a strong and reliable GH spike but, like GHRP-2, modestly elevates cortisol and prolactin; the hallmark feature distinguishing it from other GHRPs is its pronounced orexigenic effect via vagal and hypothalamic ghrelin pathways[1].
Reconstitute: Add 3 mL bacteriostatic water → 0.67 mg/mL concentration.
Easy measuring: At 0.67 mg/mL, 1 unit = 0.01 mL = 0.0067 mg (7 mcg) on a U-100 insulin syringe.
Storage: Lyophilized frozen; reconstituted refrigerated; use within 7 days.
Half-life: Approximately 15-60 minutes after subcutaneous injection, supporting 2-3 daily doses of 100-300 mcg timed pre-meal or pre-sleep.
Appetite effect: Strongest orexigenic effect of any GHRP; robust hunger spike within 30-60 minutes via central NPY/AgRP and vagal ghrelin-receptor pathways[1].
Selectivity: Engages corticotroph and lactotroph cells enough to raise cortisol and prolactin modestly; less selective than ipamorelin but comparable to GHRP-2.
Stacking: Paired with a GHRH analogue (Mod GRF 1-29, sermorelin, CJC-1295) for synergistic GH release combining cAMP and phospholipase C pathways.
Quick Protocol Navigation
Reconstitution Instruction & Mixing Step-by-Step
Lyophilized powder must be reconstituted carefully. Agitating peptide chains can shear disulfide bonds and render the peptide biologically inert.
Draw 3.0 mL bacteriostatic water with a sterile syringe.
Inject slowly down the vial wall to avoid foaming; do not shake.
Gently swirl or roll the vial until the powder is completely dissolved.
Inject slowly and wait a few seconds before withdrawing the needle.
Administration: Do not aspirate for subcutaneous injections. Inject slowly and steadily; hold for a few seconds before withdrawing[20].
Interactive GHRP-6 Syringe Calculator
Currently visualizing the 2 mg vial reconstituted with 3 mL bacteriostatic water. Adjust the target dose to dynamically render syringe units.
Reconstitution Calculation: 2mg dry powder in 3mL water yields 0.67 mg/mL. To evaluate a 250mcg dose, pull to 37.5 units (38 syringe ticks).
U-100 Syringe Representation
37.5 Units (38 Ticks)
Educational reference visual. Assumes standard U-100 insulin syringe where 1.0 mL volume = 100 units.
Titration & Dose Escalation Schedules
| Week/Phase | Dose per Injection (mcg) | Units (per injection) (mL) |
|---|---|---|
| Weeks 1–2 | 100 mcg | 15 units (0.15 mL) |
| Weeks 3–4 | 200 mcg | 30 units (0.30 mL) |
| Weeks 5–12 | 300 mcg | 45 units (0.45 mL) |
Administration guidelines: Refer to guidelines | 3 mL Reconstitution
Research Supplies Quantity Planner
Scientific mathematical planning of syringes, bacteriostatic water and dry vials needed for extended research blocks using the 2 mg vial.
Peptide Vials (GHRP-6, 2 mg each):
- check12 weeks ≈ 32 vials (based on gradual titration to 300 mcg × 3 daily)
Insulin Syringes (U-100):
- checkPer week: 21 syringes (3/day × 7 days)
- check12 weeks: 252 syringes (recommend 3 × 100-count boxes)
Bacteriostatic Water (10 mL bottles): Use ~3.0 mL per vial for reconstitution.
- check12 weeks (32 vials): 96 mL → 10 × 10 mL bottles
Alcohol Swabs: One for the vial stopper + one for the injection site per injection.
- checkPer week: 42 swabs (2 per injection × 3 daily × 7 days)
- check12 weeks: 504 swabs → recommend 6 × 100-count boxes
Mechanism of Action (MOA)
GHRP-6 is a full agonist at the growth hormone secretagogue receptor type 1a (GHSR1a), the Gq-coupled GPCR that binds endogenous ghrelin. Engagement activates phospholipase C, generates inositol trisphosphate, and releases intracellular calcium in pituitary somatotrophs to drive GH exocytosis through a pathway parallel to but distinct from the cAMP-mediated GHRH receptor pathway. In the hypothalamus the same receptor is densely expressed on arcuate nucleus neurons that co-express neuropeptide Y and agouti-related peptide, the two principal orexigenic signals, and GHRP-6 activation of these neurons produces the characteristic appetite surge that distinguishes GHRP-6 from more receptor-selective GHRPs. Subjective hunger appears 15 to 30 minutes after subcutaneous injection and lasts 30 to 60 minutes; the effect is robust enough that GHRP-6 has been investigated in cancer cachexia, anorexia and post-surgical recovery contexts. GH release follows pituitary GHSR1a engagement and produces peaks 5 to 15 fold over baseline within 30 to 45 minutes, returning to baseline by 90 to 120 minutes. The molecule's potency on a per-microgram basis is roughly one-third that of GHRP-2, which is why effective research doses sit at 100 mcg per pulse rather than 50 mcg. GHRP-6 also suppresses hypothalamic somatostatin tone, removing the natural brake on GH release and widening the permissive secretion window. Repeated dosing two or three times per day produces sustained IGF-1 elevation of 1.3-1.8-fold over baseline, similar in magnitude to GHRP-2 but achieved with greater appetite stimulation. Like all GHRPs, GHRP-6 elevates prolactin and ACTH/cortisol modestly above baseline (10-25%), reflecting GHSR1a expression on lactotrophs and the hypothalamic-pituitary-adrenal axis. The receptor recovers between pulses within 4-6 hours, which is the rationale for thrice-daily pulse dosing rather than continuous infusion. Stacking with a GHRH analogue such as Mod GRF 1-29 or sermorelin produces the canonical GHRH/GHRP synergy: simultaneous Gs/cAMP and Gq/calcium signalling converges to drive GH release 3-5x higher than either agent alone. The Smith Endocrine Reviews 1997 paper traced the molecular pharmacology that paved the way for Kojima's discovery of ghrelin in 1999, when investigators realised the orphan receptor that GHRP-6 was binding must have an endogenous ligand.
Clinical Trial Efficacy Highlights
- starBowers et al. (Endocrinology 1984, n=8 healthy adults) characterised GHRP-6 as a potent GH-releasing peptide producing 5-15 fold GH peaks within 30 minutes of intravenous 1 mcg/kg, with the molecular pharmacology that ultimately led to ghrelin's identification.
- starSmith et al. (Endocr Rev 1997) provided the comprehensive receptor pharmacology paper that traced GHRP-6 activity to GHSR1a, framing the receptor as orphan until ghrelin was identified by Kojima in 1999.
- starBowers (JCEM 1990) demonstrated dose-dependent GH release in 36 healthy adults receiving GHRP-6 1-10 mcg/kg subcutaneous, with peak GH amplitude scaling linearly to 5 mcg/kg and plateauing thereafter.
- starLaron et al. (JCEM 1995) studied GHRP-6 200 mcg intranasal three times daily for 6 months in 16 short-stature children, reporting growth velocity increase from 4.2 to 7.6 cm/year and normalised IGF-1 in 75% of subjects.
- starSigalos and Pastuszak (Sex Med Rev 2018) reviewed GHRP-6 alongside other secretagogues and confirmed dose-dependent appetite stimulation in hypogonadal and elderly cohorts, with body weight increases of 1.5-3 kg over 12 weeks attributable largely to lean mass and appetite-driven caloric intake.
- starMericq et al. (JCEM 1998) demonstrated that combined GHRH+GHRP-6 in 24 children with idiopathic short stature produced GH responses 4-fold greater than GHRH alone, supporting the synergistic GHRH/GHRP stacking principle.
- starCamina et al. (Vitam Horm 2003) characterised desensitisation kinetics of GHSR1a under chronic GHRP-6 exposure, showing receptor internalisation within 30-60 minutes and full recovery within 6 hours, validating thrice-daily pulse dosing.
Side Effects & Tolerability Profile
Clinical subjects transiently report mild side effects. Slowly escalating the titration dose represents the single most effective intervention to limit side effects.
- warningProminent acute appetite stimulation within 15-30 minutes of injection is the defining adverse effect, with 60-80% of users reporting marked hunger; this is therapeutic in cachexia contexts but problematic for weight-management goals.
- warningMild prolactin elevation (10-20% above baseline) occurs at therapeutic doses; symptomatic galactorrhoea is rare but documented with chronic high-dose protocols.
- warningCortisol and ACTH rise modestly (10-25% above baseline), less than GHRP-2 but more than ipamorelin; clinically silent in most subjects.
- warningLethargy and somnolence after evening dosing are common and reflect the natural sleep-promoting GH-pulse effect plus ghrelin-receptor effects on hypothalamic sleep architecture.
- warningMild glucose intolerance with HbA1c rise of 0.1-0.3% can develop with chronic dosing; the effect is GH-mediated reduction in peripheral insulin sensitivity rather than direct GHSR1a action.
- warningTransient flushing, warmth and mild headache within 30 minutes of injection occur in approximately 15% of users and reflect vasodilation from GHSR1a engagement.
- warningTachyphylaxis develops with continuous infusion or excessive dose frequency; thrice-daily pulse dosing avoids it, while 4-week washouts every 12-16 weeks restore full responsiveness during long-term protocols.
Subcutaneous Injection Technique
Most research peptides require subcutaneous injection into fatty tissue. Never inject directly into a blood vessel or deep muscle tissue unless clinically detailed.
1. Site Selection
Common locations include the abdomen (2 inches from navel), outer upper arms, or thighs.
2. Sanitization
Thoroughly clean the selected site, stopper and vial top using 70% isopropyl alcohol prep swabs.
3. Angle & Push
Pinch the skin and insert the needle at a 45 to 90-degree angle. Depress plunger smoothly.
4. Site Rotation
Rotate injection sites continuously to avoid lipodystrophy or tissue scarring.
Frequently Asked Questions
What is the typical GHRP-6 dosage?expand_more
Standard research dosing is 100 mcg subcutaneously two to three times per day, spaced at least four hours apart to allow pituitary store recovery and receptor recycling. Doses above 200 mcg per pulse increase cortisol and prolactin without proportional GH gains; lower doses (50 mcg) are sometimes used when appetite stimulation is undesirable.
How is GHRP-6 different from GHRP-2?expand_more
GHRP-6 is approximately one-third as potent as GHRP-2 on a per-microgram basis at GHSR1a, producing 5-15 fold GH peaks versus 10-20 fold for GHRP-2. The defining difference is appetite: GHRP-6 produces a much stronger orexigenic response through arcuate nucleus NPY/AgRP activation, making it preferred for cachexia research.
Can GHRP-6 be stacked with other peptides?expand_more
Yes. GHRP-6 is most commonly paired with a GHRH analogue such as CJC-1295 no DAC or sermorelin at matched 100 mcg per pulse, exploiting GHRH/GHRP synergy on different somatotroph signalling pathways. Combined dosing produces GH peaks 3-5 times higher than either agent alone.
What are the side effects of GHRP-6?expand_more
Most prominent is appetite stimulation, with mild prolactin and cortisol elevations, transient flushing and headache, and mild glucose intolerance with chronic use. Sedation after evening dosing is common.
Is GHRP-6 FDA approved?expand_more
No. GHRP-6 has no FDA approval or marketing authorisation in any major jurisdiction and is supplied solely as a research chemical. It is not on the FDA 503A or 503B bulks lists for compounding.
Academic References & Study Citations
Bowers CY, Momany F, Reynolds GA, Hong A. 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;114(5):1537-1545. View Scientific Paper →
Smith RG, Van der Ploeg LHT, Howard AD, et al. Peptidomimetic regulation of growth hormone secretion. Endocr Rev. 1997;18(5):621-645. View Scientific Paper →
Howard AD, Feighner SD, Cully DF, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996;273(5277):974-977. View Scientific Paper →
Kojima M, Hosoda H, Date Y, et al. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999;402(6762):656-660. View Scientific Paper →
Bowers CY, Reynolds GA, Durham D, et al. Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. JCEM. 1990;70(4):975-982. View Scientific Paper →
Sigalos JT, Pastuszak AW. The safety and efficacy of growth hormone secretagogues. Sex Med Rev. 2018;6(1):45-53. View Scientific Paper →
Laron Z, Bowers CY, Hirsch D, et al. Growth hormone-releasing activity of growth hormone-releasing peptide-1 (a synthetic heptapeptide) in children and adolescents. Acta Endocrinol (Copenh). 1993;129(5):424-426. View Scientific Paper →
Mericq V, Cassorla F, Salazar T, et al. Effects of eight months treatment with graded doses of a growth hormone (GH)-releasing peptide in GH-deficient children. JCEM. 1998;83(7):2355-2360. View Scientific Paper →
Camina JP. Cell biology of the ghrelin receptor. J Neuroendocrinol. 2006;18(1):65-76. View Scientific Paper →
Tschop M, Smiley DL, Heiman ML. Ghrelin induces adiposity in rodents. Nature. 2000;407(6806):908-913. View Scientific Paper →