Ipamorelin is a fascinating new muscle building discovery that
is getting a lot of attention in the bodybuilding world. It is
a synthetic peptide that has powerful Growth Hormone releasing
properties. And these GH releasing properties are what is of
interest to athletes and bodybuilders since they can make a
tremendous difference in the amount of muscle you can grow and
how quickly you burn fat.
Ipamorelin is a penta-peptide. (Aib-His-D-2-Nal-D- Phe-Lys-NH2)
And, the strength it displays may very well make regular old
Growth Hormone (GH) obsolete. But what athletes and bodybuilders
really want to know is what is this wonder peptide capable of
doing, how is it used, and how does it compare to the other GHRP
Athletes are taking Ipamorelin in a 200mcg -300mcg dosage, two
or three times daily, using a tiny insulin needle to inject.
They usually start with the lower dose since side effects can
include headaches or what feels like a head-rush. Ipamorelin can
be taken at anytime but taking it about 30-45 minutes before a
workout would seem ideal because of the pulse in Growth Hormone
(GH) it creates allowing for maximum growth.
Studies on the effects of Ipamorelin on bone growth, body
weight, and GH release showed some interesting conclusions.In
one experiment, various doses were administered over the course
of 15 days to test the group's reactions.
There was a distinct and dose-dependent effect on body weight
gain however, the treatment group did not show a change in total
IGF-I levels. Nor did the treatment group produce serum markers
of bone development. For example, the number of cells in the
wide portion of the tibia (the shinbone) did not change
significantly. This is a good thing because it suggests muscle
growth with less potential for deformity of bone or cartilage.
The reaction of the pituitary to an aggressive i.v. dose of
Ipamorelin showed that plasma GH levels were notably reduced
whereas they were unchanged after a comparable dose of GHRH.
This is actually a good thing as it suggests that Ipamorelin may
not decrease your body's natural GH production - further
demonstrating that Ipamorelin is a selective GH releaser.
Ipamorelin does not induce hunger making it advantageous to
those on a restricted calorie diet. And obviously, Ipamorelin's
side-effects are enhanced when combined with anabolic steroids
since they too influence Growth Hormone/Insulin Growth Factor
release and production.
Another document states that in healthy swine, Ipamorelin
released GH with a consistency that is very comparable to
GHRP-6. Also noteworthy was that none of the GH releasers tested
affected FSH, LH, PRL or TSH blood serum plasma levels.
Ipamorelin in theory may increase Acetylchloine or Cortisol when
used in higher dosages. However, and increase in Acetylchloine
or Cortisol is even more likely with GHRP-2 and GHRP-6. In fact,
in the case of Ipamorelin, there was little to no rise in
Acetylcholine and Cortisol blood plasma levels even at
injections more than 200 times higher than the effective dosage
for comparable GH release.
This clearly proves that Ipamorelin is the first successful GHRP
receptor agonist or chemical that binds to a receptor of a cell
and triggers a response by that cell with a specific selectivity
for the promotion of GH release by itself.
Another advantage to Ipamorelin is that it doesn't cause sudden
spikes in prolactin or cortisol as does GHRP-2 and GHRP-6.
Ipamorelin is slower in its delivery unlike GHRP's which spike
GH levels at a more rapid rate. The slower release is more
natural and has a more sustained effect.
All in all it looks as if Ipamorelin is the new wave in GH
releasing peptides. It appear to be more potent, longer lasting
and potentially safer to use in the long run. More studies are
being conducted all the time but as it stands, Ipamorelin looks
like a serious contender in the arsenal of anabolic advancement.
Biological Activity of Ipamorelin
Ipamorelin is a selective growth hormone secretagogue and
agonist of the ghrelin receptor. In pentobarbital anaesthetised
rats, ipamorelin released GH with a potency and efficacy
comparable to GHRP-6 (ED50 = 80±42 nmol/kg and Emax = 1545±250
ng 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). The
specificity for GH release was studied in swine.
References on Ipamorelin:
 Venkova K et al. J Pharmacol Exp Ther. 2009
Ipamorelin, the first selective growth hormone
Kirsten Raun, Birgit Sehested Hansen, Nils Langeland
Johansen, Henning Thøgersen, Kjeld Madsen, Michael Ankersen and
Peter Høngaard Andersen
(Departments of GH Biology, Assay and Cell Technology, Medical
Chemistry Research, Health Care Discovery, Novo Nordisk A/S,
Novo Nordisk Park,
DK-2760 Ma°løv, Denmark)
The development and pharmacology of a new potent growth hormone
(GH) secretagogue, ipamorelin,
is described. Ipamorelin is a pentapeptide
(Aib-His-D-2-Nal-D-Phe-Lys-NH2), which displays high GH
releasing potency and efficacy in vitro and in vivo. As an
outcome of a major chemistry programme,
ipamorelin was identified within a series of compounds lacking
the central dipeptide Ala-Trp of growth
hormone-releasing peptide (GHRP)-1.
In vitro, ipamorelin released GH from primary rat pituitary
cells with a potency and efficacy similar
to GHRP-6 (EC50 ¼ 1.360.4 nmol/l and Emax ¼ 8565% vs 2.260.3
nmol/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 ¼ 80642 nmol/kg and Emax ¼ 15456250 ng GH/ml vs
115636 nmol/kg and
11676120 ng GH/ml).
In conscious swine, ipamorelin released GH with an ED50 ¼
2.360.03 nmol/kg and an Emax ¼
6560.2 ng GH/ml plasma. Again, this was very similar to GHRP-6
(ED50 ¼ 3.961.4 nmol/kg and
Emax ¼ 7467 ng GH/ml plasma). GHRP-2 displayed higher potency
but lower efficacy (ED50 ¼
0.6 nmol/kg and Emax ¼ 5666 ng GH/ml plasma).
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. The specificity of ipamorelin makes
this compound a very interesting
candidate for future clinical development.