GHRP-2

Growth hormone secretagogue · Also known as Pralmorelin, KP-102, Growth Hormone Releasing Peptide-2

What is ghrp-2?

A synthetic six-amino acid peptide that stimulates growth hormone release by activating the ghrelin receptor (GHS-R1a). It was the first growth hormone secretagogue introduced into clinical use and is approved in Japan as a diagnostic agent for GH deficiency.

GHRP-2 has been studied in numerous human clinical trials spanning decades, including studies in GH-deficient children and healthy adults. It is approved in Japan under the brand name Pralmorelin for diagnosing adult and pediatric growth hormone deficiency. Among the GHRP family, it is considered the most potent for GH stimulation while producing fewer appetite-related side effects than GHRP-6.

Key takeaway: GHRP-2 is the most clinically validated growth hormone releasing peptide, approved in Japan for GH deficiency diagnosis, with well-characterized dose-response data in humans.

Benefits & evidence

Growth hormone release High confidence
Improved body composition Moderate confidence
Cytoprotective effects Preliminary confidence
Sleep quality improvement Preliminary confidence
Recovery support Preliminary confidence

How it works

GHRP-2 acts as a ghrelin receptor (GHS-R1a) agonist on pituitary somatotrophs, triggering a potent release of growth hormone. It works through a different mechanism than GHRH, activating phospholipase C and increasing intracellular calcium rather than using the cAMP pathway. This means GHRP-2 and GHRH have synergistic effects when used together, producing GH responses greater than the sum of their individual effects.

Beyond its pituitary action, GHRP-2 also stimulates hypothalamic GHRH neurons and suppresses somatostatin release, amplifying its GH-releasing effect. Clinical studies show peak GH levels of 30-100 ng/mL within 15-30 minutes of subcutaneous injection, representing 8-20 fold increases over baseline. Unlike ipamorelin, GHRP-2 produces mild stimulation of ACTH, cortisol, and prolactin, though these effects are less pronounced than with hexarelin or GHRP-6.

Dosing information

Typical dosing protocol
Starting dose

100 mcg/day subcutaneous

Weeks 1-2
Maintenance dose

100-300 mcg 1-3x daily subcutaneous

8-12 week cycles

In Japan, the approved diagnostic dose is 1 mcg/kg IV as a single bolus. Clinical studies in children used 5-15 mcg/kg intranasal twice daily. Research dosing for GH stimulation typically ranges from 100-300 mcg subcutaneous 1-3 times daily. Best administered on an empty stomach. Consult a healthcare provider.

Side effects

Most side effects tend to improve as your body adjusts.

Increased appetite Common
Water retention Common
Mild cortisol elevation Uncommon
Mild prolactin elevation Uncommon
Dizziness Uncommon
Injection site reaction Common

Research (10 studies)

Growth Hormone-Releasing Peptide 2 May Be Associated With Decreased M1 Macrophage Production and Increased Histologic and Biomechanical Tendon-Bone Healing Properties in a Rat Rotator Cuff Tear Model. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association · 2025
Robust growth hormone responses to GH-releasing peptide 2 in adolescents. Journal of pediatric endocrinology & metabolism : JPEM · 2024
Assessment of anterior pituitary reserve capacity based on growth hormone response to growth hormone-releasing peptide-2 test in the elderly. Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society · 2023