GHRP-2
updated
GHRP-2 (pralmorelin) is a synthetic six-amino-acid peptide that triggers growth hormone release through the ghrelin receptor, approved in Japan only as a diagnostic injection. It is used for muscle, recovery, fat loss and sleep. It reliably provokes a growth hormone pulse, and in an uncontrolled study of 15 short children, growth rose from 3.7 to 6.1 cm a year, but no controlled trial tested those goals, and it also raises cortisol, prolactin and appetite. Graded D because a diagnostic product and short hormone studies do not support repeated use for those goals.
synthetic hexapeptide ghrelin-receptor agonist
- Also called pralmorelin, KP-102, and GPA-748
- Stimulates GH through the ghrelin receptor
- Approved in Japan as a diagnostic injection
- No FDA-approved US GHRP-2 drug identified
What is GHRP-2?
GHRP-2 is pralmorelin, a synthetic hexapeptide containing non-natural amino acids. It activates the ghrelin receptor and stimulates growth-hormone secretion; it is not GHRH, growth hormone, or GHRP-6.
source: Diagnostic study · 135 participants, Chihara K et al. European Journal of Endocrinology, 2007.
source: PMDA 2025 · pralmorelin diagnostic product, Pharmaceuticals and Medical Devices Agency, revised July 2025.
What has GHRP-2 shown in people?
GHRP-2 reliably provokes an acute GH response and can be used as a diagnostic challenge in Japan. In an uncontrolled study of 15 children with short stature, mean height velocity rose from 3.7 to 6.1 cm per year at six months; six children continued for 18 to 24 months. A separate uncontrolled 10-person infusion study raised GH and IGF-1 over 30 days. These results do not establish body-composition, recovery, sleep, or longevity benefit.
Does Japanese approval validate peptide-clinic use?
No. The Japanese product is an approved diagnostic injection with a defined manufacturer, dose, route, and interpretation. It does not approve repeated subcutaneous or nasal use for performance or wellness.
source: Diagnostic study · 135 participants
source: Short-stature study · 15 children, Pihoker C et al. Journal of Endocrinology. 1997;155(1):79-86. doi:10.1677/joe.0.1550079. PMID: 9390009.
source: Older-adult study · 10 people, no control, Bowers CY et al. Journal of Clinical Endocrinology and Metabolism, 2001.
Does a GH rise prove a useful outcome?
No. A GH pulse is target engagement. Whether repeated stimulation changes lean mass, fat mass, strength, recovery, sleep, glucose control, or clinical function requires controlled outcome trials.
What are the main GHRP-2 side effects and safety issues?
The Japanese label and diagnostic studies cover controlled single-dose use. Chronic, combined, or intranasal use has weaker evidence. FDA lists serious reports but does not establish causality, and current compounded products add identity and impurity risk.
- Glucose: FDA notes reports of increased insulin requirement; frequency and causality for GHRP-2 remain unclear.
- Critical illness: deaths and infections occurred in sick study populations; those reports do not yield an event rate for healthier users.
- Product quality: the non-natural residues and possible aggregates make analytical characterization material.
source: PMDA 2025 · pralmorelin diagnostic product
source: FDA safety page · serious reports, causality unresolved, U.S. Food and Drug Administration.
Where is GHRP-2 approved?
Japan has an approved pralmorelin diagnostic injection. No FDA-approved GHRP-2 drug was identified in the United States. WADA prohibits growth-hormone secretagogues for covered athletes.
source: PMDA 2025 · pralmorelin diagnostic product
source: FDA safety page · serious reports, causality unresolved
source: WADA 2026 · GH secretagogues, World Anti-Doping Agency, effective 1 January 2026.
Studies and sources
Short-stature study · 15 children
Uncontrolled clinical study
Pihoker C et al. Journal of Endocrinology. 1997;155(1):79-86. doi:10.1677/joe.0.1550079. PMID: 9390009.
Mean height velocity increased from 3.7 to 6.1 cm per year at six months. Six children continued for 18 to 24 months, with mean height velocity of 6.0 cm per year. IGF-1 and IGFBP-3 did not change significantly.
- Participants / model
- 15 children with short stature, poor height velocity, delayed bone age, and low IGF-1; about half had growth-hormone deficiency
- Treatment
- Intranasal GHRP-2 twice daily for three months, then three times daily
- Follow-up
- 6 months in all 15 children; 18 to 24 months in 6
- Study design
- Uncontrolled clinical study
The study had no placebo or concurrent control and does not establish use in healthy adults or for physique goals.
Read the original sourceDiagnostic study · 135 participants
Clinical diagnostic study
Chihara K et al. European Journal of Endocrinology, 2007.
Seventy-seven healthy adults and 58 patients with growth-hormone deficiency received 100 micrograms intravenously. Peak GH within 60 minutes was evaluated, and a 15 microgram/L cutoff was proposed. This tests pituitary reserve; it does not show a therapeutic outcome from repeated use.
- Participants / model
- 77 healthy adults and 58 patients with growth-hormone deficiency
- Treatment
- Single 100 microgram intravenous pralmorelin challenge
- Follow-up
- 60-minute diagnostic response
- Study design
- Multicenter diagnostic-performance study
Older-adult study · 10 people, no control
Open-label human physiology study
Bowers CY et al. Journal of Clinical Endocrinology and Metabolism, 2001.
Ten older adults received continuous subcutaneous GHRP-2 for 30 days. GH and IGF-1 increased, but there was no concurrent control and the study was not designed to establish muscle, function, fat loss, or long-term safety.
- Participants / model
- 10 healthy older adults
- Treatment
- Continuous subcutaneous GHRP-2 at 1 microgram/kg/hour
- Follow-up
- 30 days
- Study design
- Open-label endocrine study
PMDA 2025 · pralmorelin diagnostic product
Official medicine label
Pharmaceuticals and Medical Devices Agency, revised July 2025.
Japan lists pralmorelin hydrochloride injection, GHRP Kaken 100, as a prescription diagnostic product for assessing severe growth-hormone secretory deficiency. The label describes a single intravenous challenge, not chronic performance or anti-aging treatment.
- Participants / model
- Patients undergoing diagnostic assessment of GH secretion
- Treatment
- Pralmorelin hydrochloride injection
- Study design
- Current Japanese approved label
FDA safety page · serious reports, causality unresolved
FDA safety communication
U.S. Food and Drug Administration.
FDA cites aggregation, peptide-impurity, immunogenicity, and unnatural-amino-acid characterization concerns. It also notes reports including increased insulin requirement, deaths in critically ill study subjects, infection, and pancreatitis, while explicitly stating that causality has not been established.
- Study design
- Agency safety summary
WADA 2026 · GH secretagogues
Sports rule
World Anti-Doping Agency, effective 1 January 2026.
Growth-hormone secretagogues are prohibited under S2 for athletes covered by the Code.
- Study design
- Binding sport rule for covered athletes
Why is GHRP-2 in D tier?
D reflects a current Japanese diagnostic product, acute hormone-response studies, and one small uncontrolled child growth study. These data do not support repeated use for muscle gain, fat loss, recovery, sleep, or general wellness.
how tiers are graded: methodology · every cited source · about reptides.
Research reference, not medical advice. Entries distinguish product labels, study doses and reported protocols. Check the linked source for the product, route and population.