G. Gordon Liddy is promoting a product "Nature's Youth HGH" which is a
dietary supplment that is purported to increase your body's production
of HGH (Human Growth Hormone.) I have three questions:
1.) Have there been any studies that show this product performs as
promised?
2.) Are there any measurable benefits of increased HGH levels for
healthy indivduals over the age of 50?
3.) There are other products claiming to do the same thing.  Are there
any clinical studies showing one product superior to another?

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Request for Question Clarification by kevinmd-ga on 03 Dec 2002 09:30 PST

Hi, thanks for asking this question.

I've done some preliminary searching.  A lot of the benefits are in
patients with pre-existing growth hormone deficiency.  If you would
like studies regarding the effects in this patient population, let me
know and I will post them in an answer.  There are also numerous small
studies that I found and I can post them in an answer if you wish.

This is the current physician thinking from the New England Journal of
Medicine:
"Growth hormone has been given to patients with obesity, osteoporosis,
muscular dystrophy, and infertility, but with no consistent benefit.
The administration of growth hormone to elderly ambulatory patients
resulted in changes in body composition similar to those that occur in
adults with growth hormone deficiency. However, no statistically
significant improvement in muscle strength or exercise tolerance
occurred. Short-term administration of growth hormone to increase
strength and endurance in athletes is no more effective than training
alone. Growth hormone should therefore not be administered to older
adults or to athletes."

Vance et al.  Growth hormone therapy in adults and children.  NEJM:
341 (16), 1999.

Let me know if you want me to post some smaller studies for you.  

Thanks,
Kevin, M.D.

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Clarification of Question by blue_bna-ga on 03 Dec 2002 18:23 PST

Thanks for the research so far.  Here's the deal - I've been taking
this product (again, it is not HGH, but is supposed to increase my own
production of HGH) for a couple of weeks and have noticed that I'm
sleeping better and feel more energetic.  Is this just a placebo
effect because I think it's effective or is there some chance that it
really is producing the desired effects?

So if you have some more studies to post or suggestions on how to
research this further,  please do so.

Thanks

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Request for Question Clarification by kevinmd-ga on 03 Dec 2002 20:05 PST

I have found some medical studies with HGH in the elderly.  As you
said, your product merely enhances your body's production of HGH - the
studies that I will cite administer actual HGH to their patients. 
Would this be acceptable data for you?  Also, can you give me a list
of ingredients in the Nature's Youth product?

Thanks,
Kevin, M.D.

Hello, thanks for asking this interesting question.  

The short answers to your questions:
1.) Have there been any studies that show this product performs as 
promised? 
Within the medical literature (i.e. objective, physician written,
peer-reviewed sources), I could not find studies with your specific
product (Nature's Youth HGH), but there are studies dealing with human
growth hormone (HGH) directly.

2.) Are there any measurable benefits of increased HGH levels for 
healthy indivduals over the age of 50? 
Yes and no.  See my answer below for details.

3.) There are other products claiming to do the same thing.  Are there
any clinical studies showing one product superior to another?
All the HGH products work the same way - to increase the body's HGH
level.  I was not able to find physician written, peer-reviewed,
clinical studies comparing one product with another.  The studies I
will discuss will deal with the effects of HGH directly on various
systems.  I want to emphasize that all information are from the
medical literature and are objective sources that may not be found on
the internet.

As I have stated before, there is no clinical consensus in using human
growth hormone (HGH) in healthy adults.  However, there are some
smaller studies that may suggest benefit.

The United States Food and Drug Administration (FDA) currently
approves the use of growth hormone in adults with growth hormone
deficiency, patients with the human immunodeficiency virus (HIV)
wasting syndrome, and girls with Turner syndrome.

Because we are presumably focusing on healthy adults, the studies I
will discuss will only focus on this patient population.

The documented decline in growth hormone and IGF I secretion with
aging led to the investigation of possible benefits of growth hormone
in healthy older men and women with relative growth hormone
deficiency, as manifested by low systemic IGF I levels. Two short-term
studies (6 months) of growth hormone administration in these patients
have demonstrated a 4% to 9% increase in lean body mass as well as a
12% to 14% decrease in adipose tissue mass (1,2).

One of these studies (2) assessed the effect of growth hormone on
functional outcomes and strength in older men with relative growth
hormone deficiency and found no benefit; subjects experienced many
troublesome side effects. A 3-month trial of growth hormone
administration to healthy elderly individuals showed a 3.3 kg increase
in lean body mass and muscle mass, with a 14% increase in strength
(3).

However, another study of growth hormone administration to healthy
elderly men failed to show any increase in muscle strength in addition
to that resulting from short-term resistance exercise (4). In
addition, a 12-week trial of growth hormone therapy in young
exercising individuals did not show any increase in either skeletal
muscle mass or strength (5). In conclusion, current evidence does not
indicate that growth hormone therapy improves functional status in the
elderly, suggesting that the age-related decline in growth hormone
secretion, or somatopause, may not be a disease per se.

Administration of growth hormone to healthy elderly men and women with
idiopathic osteoporosis led to an increase in indices of bone
formation and bone resorption (6, 7). In men, 6 months of therapy with
growth hormone to healthy elderly men has led to a 1.6% increase in
spine, but not femoral, bone mineral density (8).  The limited
efficacy of growth hormone, the lack of comparative studies with
current treatments for osteoporosis, as well as the relatively high
prevalence of side effects (9) argue against the use of growth hormone
to treat osteoporosis.

A 3-month uncontrolled trial of growth hormone in a small group of
patients with idiopathic dilated cardiomyopathy and moderate to severe
congestive heart failure demonstrated an improvement in left
ventricular ejection fraction, decreased systolic wall stress,
increased isovolumic relaxation time, and decreased peripheral
vascular resistance (10), leading to an increase in cardiac output at
rest and during exercise and improved efficiency of myocardial energy
consumption.

A recent 9-month trial of low-dose growth hormone in men with
abdominal/visceral adiposity led to improvement in glucose disposal
rate, total cholesterol and triglycerides levels, and diastolic blood
pressure (11), suggesting that growth hormone may ameliorate some of
the manifestations of primary insulin resistance (syndrome X) (11).

Finally, growth hormone has been used as an adjunct in the treatment
of both male and female infertility, given the importance of the
growth hormone-IGF axis for gonadal function (12). Studies in women
and men with hypogonadotrophic hypogonadism have shown that growth
hormone therapy decreases gonadotropin requirements (13, 14). However,
a study of adjuvant growth hormone administration to women with
polycystic ovary syndrome who were undergoing ovulation induction
failed to show any benefit (12).

So what’s the bottom line?  As you can see, there are a lot of
conflicting studies.  The consensus in the medical community is that
HGH is indicated only for the following conditions: adults with growth
hormone deficiency, patients with the human immunodeficiency virus
(HIV) wasting syndrome, and girls with Turner syndrome.  There is no
medical consensus supporting any claims by the current HGH companies
(i.e. Nature’s Youth) **when treating healthy adults**.

Please use any answer clarification before rating this answer.  I will
be happy to explain or expand on any issue you may have.

Internet search strategy:
No internet search engine was used in this research.  All sources were
from objective physician-written and peer reviewed sources.

Medline search strategy:
Human growth hormone limited to English, review, full-text articles

Thanks,
Kevin, M.D.

Bibliography: 
1. Rudman D, Feller AG, Nagraj HS, et al. Effects of human growth
hormone in men over 60 years old. NEJM. 1990;323:1-9.
2. Papadakis MA, Grady D, Black D, et al. Growth hormone replacement
therapy in healthy older men improves body composition but not
functional ability. Ann Intern Med. 1996;124:708-716.
3. Welle S, Thornton C, Statt M, et al. Growth hormone increases
muscle mass and strength but does not rejuvenate myofibrillar protein
synthesis in healthy subjects over 60 years old. J Clin Endocrinol
Metab. 1996;81:3239-3243.
4. Taaffe DR, Pruitt L, Reim J, et al. Effect of recombinant human
growth hormone on the muscle strength response to resistance exercise
in elderly men. J Clin Endocrinol Metab. 1994;79:1361-1366.
5. Yarasheski KE, Campbell JA, Smith K, et al. Effect of growth
hormone and resistance exercise on muscle growth in young men. Am J
Physiol. 1992;262(3 Pt 1):E261-267.
6. Holloway L, Butterfield G, Hintz RL, et al. Effects of recombinant
human growth hormone on metabolic indices, body composition and bone
turnover in healthy elderly women. J Clin Endocrinol Metab.
1994;79:470-479.
7. Johansson AG, Lindh E, Blum WF, et al. Effects of growth hormone
and IGF I in men with idiopathic osteoporosis. J Clin Endocrinol
Metab. 1996;81:44-48.
8. Rudman D, Feller AG, Nagraj HS, et al. Effects of human growth
hormone in men over 60 years old. NEJM. 1990;323:1-9.
9. Holloway L, Kohlmeier L, Kent K, et al. Skeletal effects of cyclic
recombinant human growth hormone and salmon calcitonin in osteoporotic
postmenopausal women. J Clin Endocrinol Metab. 1997;82:1111-1117.
10. Fazio S, Sabatini D, Capaldo B, et al. A preliminary study of
growth hormone in the treatment of dilated cardiomyopathy. NEJM.
1996;334:809-814.
11. Johannsson G, Marin P, Lonn L, et al. Growth hormone treatment of
abdominally obese men reduces abdominal fat mass, improves glucose and
lipoprotein metabolism and reduces diastolic blood pressure. J Clin
Endocrinol Metab. 1997;82:727-734.
12. Homburg R, Levy T, Ben-Rafael Z. Adjuvant growth hormone for
induction of ovulation with GnRH agonist and gonadotropins in
polycystic ovary syndrome: a randomized, double blind, placebo
controlled trial. Hum Reprod. 1995;10:2550-2553.
13. Homburg R, Eshel A, Abdalla HI, et al. Growth hormone facilitates
ovulation induction by gonadotropins. Clin Endocrinol.
1988;29:113-117.
14. Shoham Z, Conway GS, Ostergard H, et al. Cotreatment with growth
hormone for induction of spermatogenesis in patients with
hypogonadotropic hypogonadism. Fertil Steril. 1992;57:1044-1051.

The answers kevinmd posted were thoughtful and well documented. Thanks
for the assitance.
Here are two post scripts:
1.) Ingredient list on the product:
Anterior Pituitary Substance - 25mg
Glycoamino acid-glucose complex - 4200 mg  
Novel polyose complex (glucose polymers) - 1700 mg
Amino acid blend: (total 5000 mg)
 Glycine
 L-Glutamine
 L-Tyrosine
 GABA
 L-Arginine (as L-arginine HCL)
 Pyroglutamic acid
 L-Lysine (as L-lysine HCL)
Broad Bean - 10mg
2.) I realize this is purely anecdotal - but I have been a regular
(4-5 times a year) blood donor for 20+ years.  Each time I donate they
check my blood pressure and my systolic range has been 120 - 135 and 
the diastolic pressure has been 70 - 85.  This morning it was 122 -
62.

No details are given of the ingredients in this preparation, so it is
not possible to identify any relevant scientific studies. I have also
not found any proper references to the Wisconsin study mentioned on
the Nature's Youth web site.

This is exactly the kind of information I was hoping for.  I am out of
town on business until Friday Dec. 4.  When I return I will add the
ingredient list as listed on the package.  Thanks.