Ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH2) is a new and potent synthetic pentapeptide which has distinct and specific growth hormone (GH)-releasing properties. Ipamorelin was derived from GHRP1, and significantly increases plasma growth hormone (GH) levels in both animals and humans. Ipamorelin does not affect prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), or thyroid-stimulating hormone (TSH) levels, and similarly to growth hormone-releasing hormone (GHRH), Ipamorelin does not stimulate the secretion of adrenocorticotropic hormone or cortisol not even. This means, Ipamorelin is really highly selective growth hormone secretagogue for inducing the secretion of growth hormone only.
Mechanism of action
Ipamorelin triggers and stimulates Growth hormone production by mimicking the action of the natural hormone Ghrelin: In the hypothalamus binds to Ghrelin receptors (also called as Growth hormone secretagogue receptors – GHSRs, which besides its presence in the brain, can also be found in the gastrointestinal tract, heart, lung, liver, kidney, pancreas, adipose tissue and immune cells), stimulates the release of Somatocrinin (also called as Growth hormone releasing hormone – GHRH) and at the same time it inhibits the amount of Somatostatin and suppresses its action. GHRPs impacts GHRH stimulation and Somatostatin inhibition via several pathways.
Somatostatin, also called as Growth hormone inhibiting hormone – GHIH, is hormone that inhibits and brakes production of Growth hormone by the pituitary gland. While suppression of Somatostatin increases the amount of GH release per somatotrope (cell in the pituitary that release growth hormone), the GHRH increases the number of somatotropes that will release GH. Unlike other GH releasing peptides, Ipamorelin only stimulates GH release in a manner very similar to that of Growth hormone releasing hormone. Ipamorelin acts synergistically when is administered together with any synthetic analogue of GHRH (such as CJC-1295 or Sermorelin for example). Both types of peptides (ghrelin mimetics/GHSR agonists and GHRH analogues) in this case act synergistically and mutually improve their effects.
Ipamorelin released GH with a potency comparable to GHRP-6
Ipamorelin released GH from primary rat pituitary cells with a potency and efficacy similar to GHRP-6 (ECs) = 1.3+/-0.4nmol/l and Emax = 85+/-5% vs 2.2+/-0.3nmol/l and 100%). A pharmacological profiling using GHRP and growth hormone-releasing hormone (GHRH) antagonists clearly demonstrated that Ipamorelin, like GHRP-6, stimulates GH release via a GHRP-like receptor.
In pentobarbital anaesthetised rats, Ipamorelin released GH with a potency and efficacy comparable to GHRP-6 (ED50 = 80+/-42nmol/kg and Emax = 1545+/-250ng GH/ml vs 115+/-36nmol/kg and 1167+/-120ng GH/ml). In conscious swine, Ipamorelin released GH with an ED50 = 2.3+/-0.03 nmol/kg and an Emax = 65+/-0.2 ng GH/ml plasma. Again, this was very similar to GHRP-6 (ED50 = 3.9+/-1.4 nmol/kg and Emax = 74+/-7ng GH/ml plasma). GHRP-2 displayed higher potency but lower efficacy (ED50 = 0.6 nmol/kg and Emax = 56+/-6 ng GH/ml plasma).
Ipamorelin is highly selective
The specificity for GH release was studied in swine. None of the GH secretagogues tested affected FSH, LH, PRL or TSH plasma levels. Administration of both GHRP-6 and GHRP-2 resulted in increased plasma levels of ACTH and cortisol. Very surprisingly, Ipamorelin did not release ACTH or cortisol in levels significantly different from those observed following GHRH stimulation. This lack of effect on ACTH and cortisol plasma levels was evident even at doses more than 200-fold higher than the ED50 for GH release. In conclusion, Ipamorelin is the first GHRP-receptor agonist with a selectivity for GH release similar to that displayed by GHRH.
Ipamorelin results of action
The result of action of Ipamorelin is significantly increased plasma GH levels. Growth hormone is one of most important and key hormone in the body, which is involved in many important processes in the body, and impact on many biological functions. However, with age growth hormone production decreases, which can lead to many health problems and worsening overall health. Due to its high efficiency and selectivity, Ipamorelin is a very promising candidate for scientists to effectively treat growth hormone deficiency, and its intensive research is ongoing worldwide.
Scientifically investigated possible benefits of Ipamorelin
- Improved overall regeneration of the whole body (incl. internal organs), increased cellular repair
- Anti-aging effects, rejuvenation and the ability to slow-down the aging
- Improved vitality, a feeling of energy and freshness
- Increased collagen production, healthier skin, helping to smooth out wrinkles
- Increased lean muscle mass / promoting muscle growth, strength and performance
- Reduction of excess body fat
- Increased bone mineral content
- Improved sleep and its quality
- May reduce risk of heart & cardio-vascular diseases
- Strengthened immune system
- Improved cognitive functions
Ipamorelin possible side-effects
- Carpal tunnel syndrome
- Reduced insulin sensitivity (but lesser than GHRP-6)
- Dizziness rarely
- Lethargy rarely
Does Ipamorelin build muscle?
YES: It promotes muscle growth; Ipamorelin helps promote the efficient production and use of the body’s natural growth hormones, the main result are: encouraging regeneration and rejuvenation within the cells, increase in lean muscle mass, stronger bones and other above already mentioned benefits.
Are there possible side effects / risks associated with Ipamorelin?
YES: Clinical trials have indicated that Ipamorelin is generally well-tolerated by the body. However, some undesirable effects resulting from high levels of GH and IGF-1 in the blood may still be possible. For more info, read section “Ipamorelin possible side-effects” above, please.
Does Ipamorelin cause hunger?
NO: Ipamorelin does not increase ghrelin levels and therefore will not make you hungry. While some growth hormone peptides (mainly GHRP-6 peptide) increase the production of the enzyme ghrelin, which stimulates hunger, Ipamorelin does not.
In the scientific studies and clinical trials performed, the optimal dose of Ipamorelin is often reported as 1 mcg of Ipamorelin per 1 kg body weight, three times a day.
A new potent growth hormone (GH) secretagogue Ipamorelin, is a pentapeptide, which displays high GH releasing potency and efficacy in vitro and in vivo. Compared to other GHR peptides (such as GHRP-6, Hexarelin etc.), it offers several advantages, especially ist high-selectivity – it is a highly selective stimulant of the associated natural production of GH in the body without a significant impact on the production of other hormones (FSH, LH, prolactin, TSH, ACTH, cortisol); and minimum of possible side effects. The specificity of Ipamorelin and its advantages makes this compound a very interesting candidate for future clinical development.