Molecular Formula : C149H246N44O42S Molecular Weight : 3357.96 CAS No. : 86168-78-7
Sequence: H-Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2
For RESEARCH PURPOSES ONLY
Sermorelin, sometimes called GRF 1-29, is a growth hormone releasing
hormone analogue. It is a 29-amino acid polypeptide representing the
1-29 fragment from endogenous human growth hormone releasing hormone,
and is thought to be the shortest fully functional fragment of GHRH. It
is used as a test for growth hormone secretion. Used extensively in
Anti-aging Therapy often in conjunction with Testosterone in men. Safer
alternative to Human Growth Hormone.
Sermorelin acetate is the acetate salt of an amidated synthetic
29-amino acid peptide (GRF 1-29 NH 2 ) that corresponds to the
amino-terminal segment of the naturally occurring human growth
hormone-releasing hormone (GHRH or GRF) consisting of 44 amino acid
residues.
It stimulates the pituitary gland to naturally produce increased
amounts of human growth hormone. Sermorelin Acetate is a truncated
analog of a growth hormone releasing factor (GRF 1-44) that is naturally
produced by the brain to stimulate pituitary production of human growth
hormone. The increased volume of human growth hormone (hGH) produced by
the pituitary gland causes an increase in the production of
Insulin-Like Growth Factor-1 (IGF-1) by the liver and results in the
excellent benefits of this peptide.

As a result of Sermorelin Growth Hormone (GHRH) Therapy,
the increased volume of human growth hormone (hGH) secreted by the
stimulated pituitary gland is converted by the liver into IGF-1. The
increased amount of IGF-1 in the blood stream results an increase in
metabolism and growth of new cells within the body's organs and bones.
This peptide has been shown to increase lean muscle mass, reduce body
fat, increase bone density, enhance the immune system, and strengthen
the heart, as well as, other organs of the body. Since the increased
volume of human growth hormone is produced by the body's pituitary
gland, the body's endocrine system will not allow more growth hormone to
be produced by the Sermorelin GH-RH stimulation of the pituitary than
the body can safely process within the endocrine self-monitoring system.
.
Many research studies have concluded that sermorelin is a
well tolerated analogue of GHRH which is suitable for use as a
provocative test of growth hormone deficiency (Prakash and Goa 1999).
Is sermorelin the ‘new’ GH?
Sermorelin is being heralded as the breakthrough for the delivery of
growth hormone (GH). GH itself is a hormone that has been recognised for
a long time as having significant effects as an anti-aging tool, ever
since Dr. Daniel Rudman’s experiments in the 1980’s. Those clinical
trials suggested that over some months injectable GH could reverse
biological age in the 60-80 year old group by as much as 20-years;
factors that were measured included fat to muscle ratios, skin thickness
and elasticity, hair growth and density, hand grip strength, plus there
were positive reports of improved libido, energy and well being levels.
But GH has always had to be used by injection to be efficacious and has
required some careful blood monitoring to ensure overdosing does not
take place. Furthermore, numerous governments have now placed
restrictions on injectable GH and its classification as an anabolic
steroid has reduced its availability.
So what about sermorelin? In this interview, a world class anti-aging
physician and one of the key researchers of sermorelin- Dr. Richard
Walker discusses it in detail with IAS’s Phil Micans.
Phil: Dr. Walker, thank you very much for taking time today out of your
busy schedule to discuss with me the role of sermorelin and GH in aging.
I wonder if I may ask you, just to begin with, could you please inform
our readers of your background?
Dr. Walker: Hi Phil. I’m glad to be here to discuss the use of
sermorelin as a neuroendocrine intervention in aging. It’s been the
subject of my research for many years. Regarding my background, I first
focused my studies on pharmacy for which I received a BS degree from
Rutgers University. Subsequently, I realized that my greatest interests
were in the study of physiology and biochemistry, so as to better
understand the normal human condition across the life span. Accordingly,
I received an MS in Biochemistry from New Mexico State University and a
PhD in comparative physiology from Rutgers University. Immediately
after receiving my terminal degree I accepted the position of Assistant
Professor of Biology at Clemson University and became tenured faculty at
that institution after a few years. However, I realized that I was
still lacking specialty training to complete my education. To fill this
void I accepted an internship in neuroanatomy at Emory University
College of Medicine, and then postdoctoral fellowships in
neuroendocrinology and neuropharmacology at Duke University College of
Medicine (Center for the Study of Aging and Human Development) and the
University of California, Berkeley, respectively. Thereafter, I again
received faculty tenure, this time at the University of Kentucky College
of Medicine (Department of Anatomy and Molecular Biology/Sanders-Brown
Research Center on Aging). Based upon my background and research at the
UK, I was recruited to serve as Director of Reproductive Toxicology at
SmithKline Beecham Pharmaceutical Corp and also as Research Professor in
the Department of Pharmacology at the Medical College of Pennsylvania.
Thereafter, I moved my research program to the University of South
Florida (USF), where I also served as Director of Compliance and
Director of USF CARES (Clinical Alliance for Research, Education and
Service). Over the course of my academic career I’ve been fortunate to
have been the recipient of many federal (NSF, NIH, DOD), state and local
research grants which have allowed me to publish extensively in my
specialty field of interest; that of understanding the cause of
senescence and treating functional deficits associated with organismal
aging. Since retiring from academia, I serve as Editor-in-Chief of the
peer-reviewed, MedLine referenced journal, Clinical Interventions in
Aging, a source of evidence based information for practitioners of
age-management medicine published by Dove Medical Press (Auckland and
London). In addition I head a consulting firm for physicians and health
care practitioners of age-management medicine called Paradox Regulatory
and Scientific Services, Inc. I hope that this overview hasn’t been too
wordy and boring for your audience.
Phil: Surely not! Indeed it’s very impressive and I am aware that your
name has appeared on the majority of published papers related to the
role and effects of sermorelin. So I suppose the next obvious question
would be to ask you, can you please tell us what sermorelin is?
Dr. Walker: Sermorelin is the bioactive analog of growth hormone
releasing hormone or GHRH. GHRH is a neuropeptide that is released from
specific axon terminals of tuberoinfundibular neurons into the portal
capillary system that brings blood to the pituitary gland. As the name
implies, the neuropeptide, GHRH, is produced in neurons, specifically
those located in the basolateral region of the hypothalamic arcuate
nucleus. When GHRH arrives in the pituitary gland via the portal
capillary system, it binds to specific receptors on somatotrophs, the
cells that produce and secrete human growth hormone (hGH). Upon binding
it causes somatotroph DNA to transcribe message (make messenger RNA;
mRNA) and also to translate that message into protein (hGH). The final
hGH product is stored in the pituitary until being released by more GHRH
stimulatory signals. As we age, production of GHRH declines while
influence of its inhibitory neurohormone, somatostatin increases. These
changes underlie the progressive loss of growth hormone production and
secretion in the pituitary that contribute to loss of muscle, increase
in fat mass, disruption of glucose homeostasis and other such
maladaptive alterations associated with aging. As a functional analog of
GHRH, sermorelin has the same activity as the naturally occurring
molecule despite the fact it has different structure. Thus, sermorelin
is used clinically to shift the imbalance between GHRH and somatostatin
in favor of the stimulatory neurohormone thereby opposing age-related,
hGH insufficiency.
Phil: So can we say that sermorelin is a bioidentical molecule?
Dr. Walker: No. Bioidentical hormones are those having the exact
structure and function as hormones that are naturally produced by the
body. These are generally end-products of neuroendocrine pathways such
as estrogen, progesterone, testosterone, hGH and others that directly
produce effects on the body but are grandually lost during aging. They
are prescribed by anti-aging physicians to replace the hormone deficits
and imbalances so as to simulate a more youthful endocrine phenotype. In
contrast, sermorelin is not an end hormone that acts directly on the
body as are the others, although it does have some direct effects on the
brain. Its major action are those of a secretagogue capable of
stimulating hGH production/secretion and thereby to initiate events
higher up in the neuroendocrine cascade, i.e., within the pituitary
gland itself. It simulates the effects of GHRH, because it an analog of
the naturally occurring neurohormone. However, it does not have the same
structure as GHRH. The natural neurohormone consists of 44 amino acids
(there are other forms, but the dominant contains 44 amino acids) while
sermorelin is smaller. The structure of GHRH was first discovered in the
1970’s by the Nobel Laureates, R. Guilleman and A. Shalley. Thereafter,
one of their students, William Wehrenberg sought to determine which
part of the GHRH molecule was needed for its pituitary stimulating
response. By eliminating individual amino acids and then examining the
remaining peptide, he found that only the first 29 amino acids were
required to stimulate pituitary production and secretion of hGH. Thus,
sermorelin was discovered, synthesized and identified as the acetate
salt of an amidated 29- amino acid peptide (GRF 1-29 NH 2 ) that
corresponds to the amino-terminal segment of the naturally occurring
GHRH. So, since sermorelin and GHRH do not have the same structure,
sermorelin is not a bioidentical hormone. However, it functions the same
as GHRH, from binding the same somatotroph receptor, to activating the
second messenger cyclic AMP and stimulating production and secretion of
hGH from the pituitary. Also, because sermorelin is a smaller molecule
than GHRH, it is more bioavailable even to the extent that it can be
effectively administered as a sublingual formulation.
Phil: That’s interesting, so sermorelin helps to induce the release GH,
but why would we want to use sermorelin in place of GH anyhow?
Dr. Walker: There are several reasons to use sermorelin in place of hGH
including legal restrictions and medical/scientific logic. Regarding the
law, recombinant hGH (rhGH) has rather specific limits on its use,
especially in the USA, where the Code of Federal Regulations restricts
doctors from prescribing it except for treatment of short stature, AIDS
wasting and pathologic, adult-onset growth hormone deficiency (AGHD).
Although some doctors have taken the position that hGH insufficiency
associated with aging is a form of AGHD, legal challenges have often
made that opinion indefensible. Thus, routine use of rhGH in
age-management medicine increases practitioner liability for potentially
severe penalties.
In addition to the potential for legal problems associated with routine
use of rhGH, the molecule also has the potential to paradoxically
accelerate age-related changes in pituitary function. Recall that aging
is associated with decline in somatotroph function due to loss of GHRH
stimulation and gain in somtatostatin inhibition. This results in
deactivation of pituitary somatotrophs, which produce and secrete
endogenous hGH. As you know, endocrine system secretory activity is
regulated by feedback. Although positive feedback occurs, the dominant
form is negative feedback. This means that as concentrations of a given
hormone increase in the circulation, they ‘feedback’ upon sites in the
pathway(s) that stimulate their production and secretion to dampen or
reduce their influence. This negative feedback lowers circulating
hormone concentrations and inhibits cellular activity within sites that
increase it. If such inhibition persists for exceptionally long periods
of time, ‘disuse atrophy’ of the stimulating site occurs such that they
eventually become dysfunctional. While rhGH is known to oppose many of
the degenerative effects of aging upon the body especially those causing
loss of muscle and increase in fat, little attention has been paid to
the fact that the hormone also accelerates the effects of aging upon the
pituitary gland itself. It causes this maladaptive effect as the
results of exaggerated negative feedback inhibition of somatotroph
function. Normally, hGH is released from the somatotroph in bursts or
episodes associated with the alternative influences of GHRH and
somatostatin arriving in the pituitary gland. Similarly, hGH from the
somatotroph feeds back upon the brain to appropriately adjust the
release of GHRH and somatostatin. This neuroendocrine regulatory network
supports form and function in all elements of the neuroendocrine axis.
However, when rhGH is injected, it causes sustained and hyper-elevated
concentrations of the hormone throughout the day, especially when
injected as a subcutaneous bolus. The persistent presence of high
concentrations of hGH in effect shuts down the cellular machinery within
the cells producing GHRH and also that within the somatotroph that
produces endogenous hGH. Alternatively, the high concentrations of
circulating rhGH stimulate cells producing somatostatin to increase
their output since the body senses what seems to be excessive
somatotroph activity. Thus, the somatotroph stimulatory centers in the
brain as well as the pituitary cells themselves receive both negative
and direct inhibition by rhGH and excessive somatostatin, respectively.
These effects exacerbate the maladaptive changes in the same sites that
normally occur during aging. Thus, and paradoxically, while rhGH may
oppose some of the undesirable anatomical changes of aging, it also
accelerates neuroendocrine decay and erosion of hormonal homeostasis
responsible for somatic senescence in the first place. In contrast,
sermorelin simulates the stimulatory effect of GHRH upon the somatotroph
and sustains normal feedback relationships because it causes natural,
episodic release of pituitary hGH. This effect results from the subtle
effect of sermorelin to stimulate hGH release while under a more
balanced influence of somatostatin. Because sermorelin does not directly
add hGH to the circulation as occurs when the rhGH is injected,
circulating amounts can be better titrated by opposing release of
somatostain upon the somatotroph. In summary then, sermorelin is better
for use in age management medicine because of at least three important
advantages over rhGH. These include the facts that:
There is no legal restriction against the use of sermorelin to sustain youthful form and function during aging.
Sermorelin does not cause circulating hGH to rise excessively and
thereby to profoundly suppress somatotroph function through disuse
atrophy, i.e., it does not simulate and/or accelerate the effects of
aging, and
More normal feedback relationships are maintained within the hGH
neuroendocrine axis allowing for more physiological profiles of hormone
production and secretion to be sustained.
Phil: Gosh there’s quite a lot there to take it. So you’re saying that
sermorelin is a safer drug to use than GH because it is ‘regulated’
inside the body- which GH itself is not- plus having read some of your
studies I know that sermorelin can even be administered via
non-injectable routes- which is not possible with GH. I’m sure a lot of
people would prefer to take a drug by mouth rather than having to inject
it each day.
Dr. Walker: Yes, rhGH is too large a molecule to be taken orally,
buccally or sublingually. Regarding the latter two routes, because rhGH
is hydrophyllic unlike lipophyllic hormones such as testosterone, it is
blocked from passing directly through the skin or in this case,
membranes of the mouth. It is also vulnerable to attack by enzymes that
destroy its folded or quarternary structure which is necessary for
stereospecific receptor binding and thus, its activity in vivo. In
contrast to the 191 amino acid content of rhGH, sermorelin contains only
29 amino acids and its receptor affinity is not dependent upon folding
of the molecule. However, despite its smaller size, it is still
vulnerable to endopeptidase attack within the gastrointestinal tract.
Such attack cleaves the molecule leaving fragments that are not
effective in stimulating somatotroph GHRH receptors. On the other hand,
if it were possible for sermorelin to pass directly from the oral mucosa
into the bloodstream bypassing the GI tract, then it could retain its
essential structure and be an effective GH secretagogue. The only
problem with this approach is that because sermorelin is a peptide, it
is polar and thus hydrophyllic. As I said previously, lipophyllic not
hydrophyllic molecules are membrane permeable. Thus, in the past
sermorelin has been administered by subcutaneous injection. Nonetheless,
recent study of pharmaceutical agents that facilitate transport of
small peptides has shown that certain combinations of alcohols, oils,
and certain acids are effective in making sermorelin bioavailable by the
sublingual route. Based upon this information, sublingual formulations
are now available to provide ‘needle-shy’ patients the more desirable
option of enjoying the benefits of sermorelin without having to inject
it.
Phil: Can I ask therefore, what kind of positive effects have been seen in patients using sermorelin?
Dr. Walker: The clinical benefits of sermorelin are not unlike those of
rhGH, and include improvements in body composition (increased muscle,
decreased fat), better skin tone, improved cognition, increased hair and
nail growth, better quality sleep, reduced risk for intrinsic diseases
e.g., heart disease, stroke, diabetes, etc., and generally good quality
of life. The only significant activity difference between the two
molecules is that the onset and progression of sermorelin-induced
benefits is slower than that for rhGH. This difference derives from two
facts including that sermorelin must first activate the somatotroph to
produce, store and release hGH and that once available for use, the
endogenus hGH is released episodically from the pituitary. This delay in
synthesis and subsequent intermittent release results in lower mean
levels of circulating hGH than result from injection of rhGH. However,
the effects of sermorelin simulate the normal physiology of
production/secretion while as previously mentioned, the high,
pharmacological levels of rhGH resulting from sc administration of the
recombinant protein are not necessarily safe nor do they achieve the
total anti-aging effects of therapy that are sought.
Phil: When should people take sermorelin and what kinds of doses are normal?
Dr. Walker: It has been suggested that sermorelin be taken at bedtime
based upon the fact that GHRH (as well as sermorelin) is known to
increase slow wave, restful deep sleep in some people. Such sleep is
associated with the large nocturnal bursts of hGH from the pituitary
gland. However, in others, sermorelin induced GH release before sleep
results in increased mental activity and may actually delay sleep onset.
Thus, depending upon specific patient results, those who benefit with
improved sleep quality from sermorelin should take it at bedtime.
Otherwise, morning or daytime administration is appropriate. No specific
time is better than another unless sleep architecture is improved.
Regarding dosage, patient specificity again is the most important
consideration. Efficacy has been reported with subcutaneous doses as low
as 0.2 mg daily; whereas some patients need as much as 1 or 2 mg daily
to gain desirable results. Because sublingual bioavailability is less
than that achieved by subcutaneous administration, the higher dose range
of 1 – 2 mg of sermorelin daily is recommended.
Phil: And of course I must also ask, what can of side effects or contraindications have been noted with sermorelin?
Dr. Walker: Remarkably, little or no side effects of sermorelin have
been reported over the course of decades that it has been used. Since it
was invented, sermorelin is known to produce antibodies in about twenty
percent of users. This is probably because the molecule is sufficiently
different from GHRH to be recognized by the body as being ‘foreign.’
However, the sermorelin antibodies have no adverse effects on the body,
are transient, disappearing after repeated use of the product, and they
are not deactivating, i.e., efficacy of sermorelin is not destroyed by
the antibodies. The only other undesirable issue is irritation or
redness at the injection site for some individuals. This effect is of
course, irrelevant to those using the sublingual formulation. All in
all, sermorelin is an extremely safe product that has never been
associated with severe adverse events.
Phil: Are there any other supplements or lifestyle changes that people
can incorporate with their sermorelin to make it even more effective?
Dr. Walker: As with rhGH, the most effective lifestyle change to enhance
the efficacy of sermorelin is regular exercise. Dynamic cardiovascular
as well as resistance exercises provide the hGH resulting from
sermorelin administration to realize its anabolic and other beneficial
effects to the maximum due to the somatic remodeling that is induced by
work-out. In addition to physical exercise, nutritional supplements
including glutamine, alanine, ornithine, ornithine alpha-ketoglutarate
(OKG), arginine pyroglutamate combined with L-lysine hydrochloride,
glycine, and gamma-amino butryric acid (GABA) have been reported to
improve the effects of hGH on the body. Many of these actually enhance
neural signaling to improve hGH release from the pituitary, and some
such as glutamine which has been reported to be reduced by rhGH
administration, should be supplemented to ensure a good source of
nitrogen for muscle repair and synthesis associated with sermorelin
administration.
Phil: Of course the internet is awash with GH agonists, many of which
are poorly studied or perhaps poorly bioavailable/ active. Where do you
see sermorelin on this list of available supplements, at least from the
perspective of its effectiveness to significantly raise GH levels in
humans?
Dr. Walker: I agree that there are numerous ‘secretagogues’ that are
marketed as being effective hGH releasers. They generally are
combinations of amino acids. In fact, most of them will release some hGH
from the pituitary. However, their effects are not reliable and for the
most part, not consistently reproducible. The reason for this fact is
that all secretagogues except for sermorelin and the ghrelin analogs
(GHRPs) are non-specific in their actions. By being non-specific I mean
that the other secretagogues are intermittently effective by sometimes
causing changes in CNS activity that favor release of GHRH from the
hypothalamus. However, these effects are not quantitative nor do the
non-specific secretagogues bind and stimulate the somatotroph directly.
On the other hand, sermorelin and the GHRP’s have specific, saturable
receptors and second messenger systems in the somatotrophs that make
their effects quantifiable and reproducible. Thus, sermorelin, which
binds the GHRH receptor, mimics the natural and primary stimulus for hGH
production and secretion by the pituitary gland. The GHRPs mimic the
effects of ghrelin which is an amplifier of the primary stimulus. As a
result of this fact, sermorelin represents the best and only true hGH
secretagogue currently available on the market.
Phil: I wanted to ask something that’s been on my mind- it’s quite well
known that GH levels rapidly fall in blood tests past the age of 35. Of
course the labs look for IGF-1 levels because of the difficulty to
examine GH levels themselves. However, there have been some studies to
suggest that GH production actually continues to be effective, even well
into our seventh decade of life, but that the pituitary gland appears
to fail to release GH into the bloodstream, hence because it never gets
delivered it never gets its jobs done. Do you feel that sermorelin may
be a missing link in this regard? By which I mean, is sermorelin not
actually stimulating the production of GH, but rather helping to release
into the blood what’s already available?
Dr. Walker: To the contrary. With advancing age, stimulation of the
pituitary by GHRH declines. As a result, pituitary hGH reserve falls,
reducing the amount of hormone available for release into the
circulation. As I previously mentioned, GHRH is responsible for
transcription as well as translation of the hGH gene residing within
somatotroph DNA. Because of this fact, as GHRH stimulation declines
during aging, less hGH is produced and consequently less secreted
because pituitary reserve declines. However, unless somatotrophs become
so atrophic that they die and are lost from the population of pituitary
endocrine cells, they are capable of recrudescence by stimulation of the
GHRH receptor with sermorelin. Under these conditions, initial hGH
secretory responses to sermorelin may be modest because pituitary
reserve is low. On the other hand, with continued stimulation with
sermorelin causing increased production of endogenous hGH, pituitary
reserve rises and the amount of hormone released into the circulation
goes up. So in conclusion, sermorelin is not only a releaser of hGH that
is present within the pituitary, it also increases its content and
thereby is perhaps one of the most effective and restorative ‘antiaging’
hormones for the neuroendocrine system that is currently available.
Phil: Fascinating! Would you care to add anything more to this exciting
debate about the role and performance of sermorelin to improve our age
related GH levels? And perhaps I should ask you, how do you personally
rate the role of GH in the battle against aging?
Dr. Walker: Really nothing more to add other than to underscore the
importance of reminding the patient that every individual responds
differently to sermorelin. Some people are more sensitive than others
because somatotroph responsiveness varies as a function of stimulation
history, e.g., age and physiological state. Thus, a bit of dose
experimentation is required to achieve patient specificity that
subserves maximum efficacy. Regarding your question about the role of
hGH in the ‘battle against aging’ I must stress that the hormone is
effective in opposing many of the consequences of aging, but has
absolutely no effect on the underlying mechanism of senescence. So while
hGH restores more youthful body composition and protects against early
onset of intrinsic diseases, the erosive influence of aging on
physiological homeostasis proceeds unabated. In a way, you can say the
hGH has greater cosmetic value than therapeutic in the battle against
aging. However, feeling good, being healthy and retaining physical and
mental vitality throughout life cannot be demeaned since these factors
all translate into good quality of life. And so, until we can attack the
cause of aging, which I have identified as developmental inertia in a
recent paper; Developmental Theory of Aging Revisited, Rejuvenation
Research, 14 (4): 429-436, 2011, treating its consequences with
sermorelin and other restorative agents to sustain the most youthful
life style possible is certainly an attractive alternative.
Phil: Dr. Walker I congratulate you on your research into this
fascinating molecule. You have accomplished much over many years and I
am pleased that at last the word about sermorelin is coming to the fore.
Thank you very much all your time with us today.
Dr. Walker: My pleasure Phil.
This product was added to our catalog on Saturday 13 October, 2012.