Growth Hormone

GHRP-2

Growth Hormone Releasing Peptide-2 (Pralmorelin)

The strongest GHRP with an approved diagnostic use

GHRP-2 (pralmorelin) is a synthetic growth hormone releasing peptide that produces the strongest GH release of the GHRP family. It is approved in Japan for diagnostic testing of GH deficiency.

GHR
💉

Admin routes

Subcutaneous, Intravenous

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Popularity

Medium

Side effects

Generally mild

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AU vendors

0 rated

Key benefits

1Strongest GH release of all GHRPs (15-40 ng/mL peak GH)
2Approved pharmaceutical in Japan (Kaken 100)
3Synergistic with GHRH analogs like CJC-1295
4Improved sleep quality and body composition

📈What to expect

1
Week 1

Improved sleep depth and vivid dreams

2
Week 2-4

Increased appetite, improved recovery from training

3
Week 6-12

Body composition changes: reduced fat, improved lean mass

Based on community reports and published research. Individual results vary significantly.

💊Dosing protocols

GH optimisation

Dose

100-300 mcg

Frequency

2-3 times daily (before meals and at bedtime)

Duration

8-12 week cycles

Sleep and recovery

Dose

100-200 mcg

Frequency

Once before bedtime

Duration

Ongoing with periodic breaks

Dosing information is sourced from published research and community protocols. This is not a recommendation. Consult a healthcare professional.

Research status|Approved diagnostic agent in Japan; off-label use elsewhere

Overview

GHRP-2 is a hexapeptide analog of met-enkephalin that stimulates GH release from the pituitary gland. Among the GHRPs, it produces the highest peak GH levels, though this comes with a stronger cortisol and prolactin spike compared to ipamorelin. It was developed by Kaken Pharmaceutical in Japan and marketed as a diagnostic agent (GHRP Kaken 100) for assessing growth hormone deficiency. In the peptide community, it is used for muscle growth, fat loss, improved sleep, and recovery. It is often combined with CJC-1295 for synergistic GH release.

⚙️How it works

GHRP-2 binds to the ghrelin receptor (GHS-R1a) on pituitary somatotrophs, triggering GH release through a calcium-dependent pathway. It also acts on the hypothalamus to stimulate GHRH release and suppress somatostatin, amplifying the GH pulse. Unlike ipamorelin, GHRP-2 also significantly increases cortisol, prolactin, and ACTH, indicating broader hypothalamic activity beyond just the GH axis.

Side effects

Increased hunger (stronger than ipamorelin)
moderateCommon
Elevated cortisol and prolactin
moderateCommon
Water retention and numbness in hands
mildUncommon

📅Research history

1984

Bowers develops GHRP-2 as a met-enkephalin analog

2004

Kaken Pharmaceutical launches GHRP-2 as a diagnostic agent in Japan

GHRP-2 vs ipamorelin

GHRP-2 produces higher peak GH levels but at the cost of more side effects. It raises cortisol and prolactin significantly, while ipamorelin is the most selective GHRP with minimal effects on other hormones. For pure GH output, GHRP-2 wins. For cleaner, side-effect-free GH release, ipamorelin is preferred. Some users start with ipamorelin and switch to GHRP-2 when they want stronger results and can tolerate the hunger and hormonal effects.

References

  1. [1]Bowers CY, et al. '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.
  2. [2]Kaken Pharmaceutical product information for GHRP Kaken 100 (Japan).

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Disclaimer: This guide is for educational and informational purposes only. It is not medical advice. The dosing protocols listed are sourced from published research and community reports and do not constitute a recommendation. Always consult a qualified healthcare professional before using any peptide. Australian regulations classify many peptides as Schedule 4 (prescription-only) substances. Check current TGA guidelines before purchasing.