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Research peptide — not a dietary supplement
GHRP-6 is a research compound, not a regulated dietary supplement. It is typically administered by injection and sold “for research use only.” The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most GHRP-6 studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 2002–2024 with a typical study size of 69 participants.
Based on 9 studies · 1 RCT · 725 total participants
Confidence
LowBy outcome
The current evidence for GHRP-6 is insufficient to assign an evidence score, based on 9 indexed studies. A synthetic hexapeptide growth-hormone secretagogue (a ghrelin-receptor / GHS-R1a agonist) promoted online to raise GH and IGF-1 for muscle and 'anti-aging'. Honest appraisal: the real human data are short pharmacokinetic and provocative-test studies showing it transiently raises GH (and cortisol) and triggers strong hunger — it is used clinically mainly as a diagnostic GH/HPA-axis stimulus, not as a treatment. Cardioprotection and tissue-cytoprotection are mostly PRECLINICAL (rat) findings, though a small open-label phase I/II stroke trial (GHRP-6 combined with EGF) reported safety and a functional-recovery signal. There are NO human RCTs for any muscle, fat-loss or anti-aging use. It is not a dietary supplement: it is an injectable 'research use only' chemical and is banned by WADA. Representative study: PMID 38638315.
The commonly studied dose of GHRP-6 is No validated human dose for any physique or anti-aging use exists. In clinical research GHRP-6 has been given as a single ~1 mcg/kg dose for provocative GH/HPA-axis testing, and at 100-400 mcg/kg in single-dose pharmacokinetic work. Anecdotal grey-market 'GH-boosting' protocols circulate online but have no clinical basis, no efficacy validation, and should not be read as a recommendation.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Mecasermin (IGF-1)
Mostly mechanism / observationalThe pharmaceutical-grade version of IGF-1 — an FDA/EMA-approved prescription injectable, but approved ONLY for a rare childhood growth disorder (severe primary IGF-1 deficiency / Laron syndrome), where it genuinely raises height velocity in clinical trials. It is the regulated counterpart to the grey-market igf-1-lr3 peptide bodybuilders inject, and shares the same core risks. Crucially, there is NO trial supporting its off-label use for muscle, performance, or anti-aging in healthy adults — and IGF-1's documented harms (hypoglycemia, intracranial hypertension, lymphoid/tonsillar hypertrophy, and a theoretical cancer concern because IGF-1 is mitogenic) are real. Not a dietary supplement, not a longevity drug.
Last reviewed June 2026 · evidence from 9 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
GHRP-6 (growth hormone releasing peptide-6)
A synthetic hexapeptide growth-hormone secretagogue (a ghrelin-receptor / GHS-R1a agonist) promoted online to raise GH and IGF-1 for muscle and 'anti-aging'. Honest appraisal: the real human data are short pharmacokinetic and provocative-test studies showing it transiently raises GH (and cortisol) and triggers strong hunger — it is used clinically mainly as a diagnostic GH/HPA-axis stimulus, not as a treatment. Cardioprotection and tissue-cytoprotection are mostly PRECLINICAL (rat) findings, though a small open-label phase I/II stroke trial (GHRP-6 combined with EGF) reported safety and a functional-recovery signal. There are NO human RCTs for any muscle, fat-loss or anti-aging use. It is not a dietary supplement: it is an injectable 'research use only' chemical and is banned by WADA.
Human data are short pharmacokinetic and diagnostic GH/HPA-stimulation studies plus one small open-label stroke trial of GHRP-6 with EGF; cardioprotection is animal-only and no trial tests physique claims, so evidence is very low.
GHRP-6 (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) is a synthetic hexapeptide growth-hormone secretagogue.
It acts as an agonist at the growth-hormone-secretagogue receptor GHS-R1a — the same receptor activated by the natural hormone ghrelin — and (for its cytoprotective effects) is thought to also engage the scavenger receptor CD36.
Activating GHS-R1a on pituitary somatotrophs evokes a pulse of growth hormone (GH), and, because GHS-R1a also sits in the hypothalamus and on appetite circuits, GHRP-6 is a potent orexigen: it strongly stimulates hunger and food intake.
The honest evidence picture is that GHRP-6's well-documented human role is as a short-acting pharmacological probe, not a marketed therapy.
In healthy volunteers a single dose produces a transient, dose-related rise in GH; it is used clinically — usually combined with GHRH — as a provocative test to diagnose GH deficiency, and it also activates the hypothalamic-pituitary-adrenal axis, raising cortisol (and prolactin), which is why it has been explored as an adrenal-insufficiency test too.
Its plasma half-life is short (distribution ~8 min, elimination ~2.5 h after IV dosing in healthy men).
Separately, a body of PRECLINICAL work in rats reports that GHRP-6 (and related GH-releasing peptides) is cytoprotective and cardioprotective — limiting cardiomyocyte apoptosis and improving cardiac function in heart-failure models, preserving tissue viability during ischemia/reperfusion in bowel, liver and kidney, and raising brain IGF-1 with neuroprotective signaling.
These are mechanistically interesting but are animal findings; none has been translated into a human outcome trial.
The one human interventional trial is a small open-label, randomized phase I/II study in acute ischemic stroke that combined GHRP-6 with epidermal growth factor (EGF): it was designed for safety and reported a favourable neurological/functional-recovery signal, but it is open-label, tests a drug combination rather than GHRP-6 alone, and does not address physique outcomes.
Critically, there are NO randomized controlled trials showing GHRP-6 alone improves muscle mass, strength, body composition, fat loss or aging outcomes in people — the physique and 'anti-aging' claims are extrapolated from a transient GH/IGF-1 surrogate rise plus animal data.
GHRP-6 is NOT a regulated dietary supplement: it is sold 'for research use only', is injectable, its grey-market identity/purity/sterility are unverified, it strongly stimulates appetite and raises cortisol/prolactin, its long-term effects are unknown, and it is a WADA-prohibited substance.
Overall evidence for any benefit claim is therefore unproven and rests on short biomarker studies plus preclinical cytoprotection data.
GHRP-6 binds and activates the growth-hormone-secretagogue receptor GHS-R1a — the receptor for the natural hormone ghrelin — on pituitary somatotrophs and in the hypothalamus. This is the core mechanism behind its two best-documented human effects: a transient GH pulse and a strong stimulation of appetite.
Activating GHS-R1a triggers release of growth hormone from the pituitary; because the receptor also engages the hypothalamic-pituitary-adrenal axis, GHRP-6 additionally raises cortisol (and prolactin). In humans this is short-lived, which is why GHRP-6 is used mainly as a provocative diagnostic stimulus (often with GHRH), not as a sustained treatment.
How GHRP-6 works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
No validated human dose for any physique or anti-aging use exists. In clinical research GHRP-6 has been given as a single ~1 mcg/kg dose for provocative GH/HPA-axis testing, and at 100-400 mcg/kg in single-dose pharmacokinetic work. Anecdotal grey-market 'GH-boosting' protocols circulate online but have no clinical basis, no efficacy validation, and should not be read as a recommendation.
Can be taken without food
| Form | Type |
|---|---|
| 💊None — no form has validated human efficacy or an approved standard | Recommended |
GHRP-6 is a research chemical, not an approved drug or dietary supplement. There is no quality-controlled, regulator-sanctioned product. It is most established as a diagnostic GH/HPA-axis stimulus rather than a treatment.
Minimum: 1 weeks
Optimal: 4 weeks
Cycling: Not required
Note: No evidence-based timing for any benefit exists. The GH pulse is short-lived and the peptide strongly stimulates hunger; grey-market protocols vary and are unvalidated.
Dose-response data unavailable. The current published research for GHRP-6 does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Most human GHRP-6 data are short pharmacokinetic and provocative-test studies; the only interventional trial is a small open-label phase I/II stroke study of GHRP-6 combined with EGF (a safety study with a functional-recovery signal). No randomized trial has tested whether GHRP-6 improves muscle, strength, fat loss, recovery or any aging outcome in people. Physique and 'anti-aging' claims are extrapolated from a transient GH/IGF-1 surrogate rise plus animal data, not measured.
In healthy adults a single dose produces a short, dose-related rise in growth hormone; this is why GHRP-6 (usually with GHRH) is used clinically as a provocative test for GH deficiency. It is a biomarker effect, not a clinical outcome, and is short-lived.
As a ghrelin-receptor agonist, GHRP-6 reliably increases hunger and food intake. For some this is a desired effect (e.g. for bulking); for most it is an unwanted, hard-to-control side effect.
GHRP-6 activates the hypothalamic-pituitary-adrenal axis and raises cortisol, and can raise prolactin. This is exploited diagnostically (adrenal-insufficiency testing) but is an unwanted off-target effect for performance use.
In rats, GHRP-6 (and related GH-releasing peptides) improved cardiac function and cachexia in heart failure, suppressed cardiomyocyte apoptosis, preserved tissue during ischemia/reperfusion in several organs, and raised brain IGF-1 with neuroprotective signaling. Preclinical findings — not demonstrated in humans.
Avoid — never studied in pregnancy or lactation.
Avoid — GH/IGF-1 elevation is a theoretical proliferative risk that has never been evaluated for this peptide in humans.
Avoid or use only under medical supervision — GH excess raises glucose and reduces insulin sensitivity, and the peptide increases appetite.
Avoid — GHRP-6 is a WADA-prohibited growth-hormone secretagogue (Section S2) and is detectable in anti-doping testing.
Growth hormone raises blood glucose and reduces insulin sensitivity, and GHRP-6 increases appetite/food intake — together these could counteract glucose-lowering therapy. This has not been characterized for GHRP-6 specifically, so any combination is unpredictable.
GHRP-6 activates the hypothalamic-pituitary-adrenal axis and raises cortisol; glucocorticoids in turn modulate the GH response to GHRP-6. The net interaction and its clinical relevance are not established for performance use.
Tip: Inherent to ghrelin-receptor agonism; there is no reliable way to suppress it. Can drive unwanted weight gain.
Tip: An on-target effect of HPA-axis activation; not specifically mitigable. Relevant for anyone monitoring these hormones.
Tip: There is no verified safe product; risk stems from unregulated grey-market sourcing rather than the peptide alone.
Tip: Reported with GH/GH-secretagogue overstimulation generally; not systematically characterized for GHRP-6 beyond short studies. Lower dose or stop.
Timing is flexible for GHRP-6 — consistent daily use matters more than the time of day. GHRP-6's half-life is short (elimination ~2.5 h after IV dosing), so any GH pulse is transient.
GHRP-6 should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are strong appetite stimulation / increased food intake, cortisol and prolactin elevation, injection-related risks (infection, abscess, contamination from non-sterile 'research-use-only' product). Use caution if any of these apply to you: Pregnancy and breastfeeding — never studied; avoid entirely; Active cancer or history of cancer — GH/IGF-1 elevation is a theoretical proliferative concern, never evaluated for this peptide in humans; Diabetes / impaired glucose tolerance — GH excess promotes insulin resistance, and the peptide stimulates appetite.
Insulin (bodybuilding use)
Mostly mechanism / observationalInsulin is a life-saving prescription hormone for diabetes — and, used illicitly by bodybuilders as an off-label 'anabolic,' one of the most dangerous performance drugs in existence. The theory is nutrient partitioning: insulin drives glucose and amino acids into muscle and suppresses muscle-protein breakdown. But there is NO controlled evidence that insulin builds muscle or improves performance in healthy, non-diabetic athletes — and a non-diabetic who injects it risks profound, sometimes FATAL hypoglycemia (coma, seizures, brain injury, death), plus fat gain. This is a harm-reduction reference documenting a popular, deadly misuse, NOT a recommendation and NOT a dietary supplement.
GHS-R1a sits on hypothalamic and reward circuits that drive hunger. Like ghrelin, GHRP-6 strongly stimulates food intake; ghrelin-receptor antagonism with [D-Lys3]-GHRP-6 conversely reduces feeding and the motivation to obtain palatable food in animals. Appetite stimulation is one of GHRP-6's most reliable effects.
Beyond the GH axis, GHRP-6 (and related GH-releasing peptides) shows cytoprotective/cardioprotective activity in animals — attributed partly to the scavenger receptor CD36 — limiting cardiomyocyte apoptosis, preserving tissue during ischemia/reperfusion, and activating pro-survival (Akt/Bcl-2) signaling with raised brain IGF-1. This is preclinical (rat) biology, not a demonstrated human effect.
Tip: No long-term human safety data exist; absence of reported harm in brief diagnostic studies is not evidence of long-term safety.