Peptide Synthesis and Guide, Part Two

GHRP : Growth Hormone Releasing Peptide

GHRP is a synthetic peptide that stimulates the release of growth hormone (GH). Unfortunately, these peptides do not only stimulate GH, they also have effects on the secretion of prolactin (PRL), ACTH/cortisol and sometimes DHEA. However, to express their maximum secretagogue activity, they need GHRH activity. They are analogues of ghrelin and therefore directly increase appetite.

This is a continuation of the article Synthesis and Peptide Guide, Part One

Different GHRP’s : GHRP-6, GHRP-2, Ipamorelin, Hexarelin…

Dosage: 1mcg/kg of body weight or 100mcg remain usual for a classic use, 200mcg seems a more profitable contribution, the maximum I.V. dose of GHRP being estimated at 2/3mcg per kg of body weight.

1. GHRP-6

Dosage : 100 to 400mcg/day

First generation GHRP, the main use of the GHRP-6 peptide is to promote food intake by stimulating the sensation of hunger and to optimize energy metabolism.

This peptide can be used in the treatment of HGH deficiency as well as cachexia (profound weakening of the organism), nutritional disorders and obesity.

It causes the stimulation of the anterior pituitary gland, and ultimately causes an increase in the release of HGH.

Since it acts directly on the feedback cycle that signals the inhibition of the HGH version, when natural HGH secretion has been prevented by long-term synthetic use, it can be used to restart natural HGH production, hence its name HGH PCT!

Moreover, this peptide targets the central nervous system by acting on the protection of neurons. It also acts on muscle strength in a very similar way to certain steroids of the Dihydrotestosterone (DHT) family.
The increased levels of growth hormone produced by the use of this peptide promote increased strength and muscle mass, stimulate fat loss, and help rejuvenate and strengthen tendons and ligaments, connective tissue and bone mass.

It also allows the liver to secrete more IGF-1.
However, if you add D-Lys3 to it, you get a modified version that does not cause the sensation of hunger.

2. GHRP-1, GHRP-2, Hexarelin: Second generation of GHRPs, with more potent secretagogic capabilities.


Dosage: 100 to 400mcg/day

It is a peptide of the GHRP family very similar in structure and function to GHRP-6. This peptide has a strong effect on the release of GH in the body. It almost promotes hunger and appetite by stimulating a version of Ghrelin (peptide in the stomach that promotes appetite and digestion).
It acts by stimulating the anterior pituitary gland to produce GH. It is used for a range of medical issues including decreased natural GH production and weight gain for abnormally thin people. Of course, we find the same effects as GHRP-6.

What is the difference between the two?

To put it simply, all GHRPs are interchangeable. The strongest in terms of impact on cortisol/prolactin levels is hexarelin, in the middle is GHRP-2 and finally GHRP-6.


Dosage : 200 to 400mcg /day.

Hexarelin is a GHRP whose structure remains very close to GHRP-6. Like the latter, its role is to release the famous youth hormone. Because of Hexarelin’s ability to increase the secretion of natural growth hormone, most of its effects are similar to those of synthetic GH, although measured to a lesser degree. The effects of its use therefore include: increased strength, growth of new muscle fibers, increased size of existing muscle fibers, neural protection, “rejuvenation” of tendons, etc.

In addition, with the use of Hexarelin, the GH receptors in the adipose tissue will stimulate the significant reduction of it.

The increased circulation and availability of GH through the use of Hexarelin results in increased levels of growth factors, for example, an increase in IGF-1 in the liver, IGF-1 being the primary factor in muscle growth in response to GH stimulation.

There is no increase in appetite with the use of Hexarelin (as opposed to the extreme increase in appetite with the GHRP-6 peptide), as Hexarelin does not disrupt levels of Ghrelin, the hormone responsible for hunger and accelerated digestion.

3. Ipamorelin

Dosage: 100 to 300mcg/day

Latest generation secretagogue. First selective GHRP-receptor agonist.

It is a polypeptide analog of ghrelin, it acts only on GH secretion, and does not raise cortisol and ACTH levels.

It is important to remember that Ipamorelin is a ghrelin mimetic, and a ghrelin analogue.

However, it does not cause the kind of hunger feelings caused by ghrp-6.

Ipamorelin acts synergistically with our own GH production or when co-administered with GHRH or a GHRH analog such as Sermorelin or cjc.
The synergy comes about because of the obvious suppression of somatostatin and increases in the par-somatotropic version of GH, while GHRH increases the number of somatotropes that
release GH.
Since it does not influence cortisol or prolactin, this makes Ipamorelin a very exciting peptide, it is as effective as ghrp-6 without increasing hunger or cortisol or prolactin levels, and it has another unique property to Ipamorelin.
A mega-dose of ipamorelin results in a mega-release of GH (up to the full amount that is actually present in the pituitary gland), whereas GHRP-2 and GHRP-6 have limits of approximately 1mcg/kg in humans for their maximum GH release.

Note from Thor49: What you should know about this family of peptides


* Ipamorelin is effective but the weakest GH “liberator”.
* GHRP-6 is very effective in the release of GH.
* GHRP-2 is slightly more effective than GHRP-6
* Hexarelin, the strongest is a little more effective than GHRP-2.


* Ipamorelin does not increase cortisol or prolactin levels at any dose.
* GHRP-6 does not increase these hormones if dosed at 100mcg but does a minimum above 100mcg.
* GHRP-2 has a stronger effect on these hormones at all dosages.
* Hexarelin has the strongest impact on cortisol and prolactin at all dosage levels, with levels in the upper range of normal.


* Ipamorelin and GHRP-6 do not desensitize as long as there are small pauses between doses (i.e. 2 hours or more).
* GHRP-2 does not desensitize in “normal” doses and if small breaks are taken between doses. At high doses it is not safe, but desensitization may occur.
* Hexarelin showed desensitization at all doses, with or without a break between doses. This effect increases after 14 days of use but can be avoided by
keeping doses low or taking a full day or two off every two weeks.

Third article in this series here