GH vs Testosterone

by Karlis
Ullis, MD with Josh Shackman, MA

I was one of the first private practitioners in the country to dispense growth
hormone as part of an overall anti-program hormone replacement program for
adults that fit the criteria of the “Adult Onset Growth Hormone Deficiency
Syndrome”. Like many other anti-aging physicians, I was extremely
impressed by the initial research on growth hormone showing dramatic
improvements in body composition, kidney function, skin, mood, well being, etc.
I have been a member of the Growth Hormone Research Society for many years and
have closely followed all the latest research on growth hormone and other adult
hormone replacement therapies. As the number of studies on growth hormone as
well as testosterone has piled up since I first began prescribing testosterone,
I believe now is the time to look back at the research and see if growth
hormone and testosterone have lived up to their promises.

It is well
established in bodybuilding circles that testosterone is superior to growth
hormone for gaining muscle. However, growth hormone still is enormously popular
and generally has a better reputation than testosterone both in bodybuilding
and in anti-aging circles. The general impression is that testosterone will
make you big, but at the price of acne, puffiness, temper tantrums, prostate
enlargement, and possibly “gyno”. Well it is acknowledged that growth
hormone is not as anabolic as testosterone, people still think of growth
hormone as a hormone that will make you lean and toned with almost no side
effects. Growth hormone also has a reputation as being the “fountain of
youth” among anti-aging enthusiasts, whereas testosterone is still
considered somewhat dangerous. The purpose of this article is to see how the
research on testosterone and growth hormone from the last few years has
supported or disputed the public’s view of these two hormones.

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Which is Better for Body Composition?

New research has shed some light on the anabolic effects of growth hormone.
Several studies in the past have shown an increase in lean body mass in
subjects taking growth hormone. However, lean body mass does not necessarily
mean muscle, but anything that is not fat and this includes water, organ tissue
growth, bone mass, and connective tissue growth. My friend Michael Mooney
(author of Built to Survive and editor of the Medibolics Newsletter) has helped
publicize the fact that not much, if any, of the lean mass gained while on
growth hormone is actually muscle. One recent study on HIV positive test
subjects showed no significant change in skeletal muscle mass after taking six
milligrams (about 18 units) per day of growth hormone for 12 weeks.(1) Another
study, also on HIV positive test subjects, also showed a lack of muscle growth
when doses of nine milligrams (roughly 27 units) per day were given.(2) Keep in
mind that HIV positive individuals are often suffering from muscle wasting
conditions, which should make them more responsive to any possible anabolic
effects of growth hormone. Growth hormone is probably equally ineffective in
healthy individuals.

One study on young (aged 22-33), highly trained athletes did show a significant
increase in lean mass after six weeks of taking 2.67 milligrams (about 8 units)
per day.(3) However this increase was only 4%, and may have not included any
muscle mass at all. It seems overwhelming clear that growth hormone is either
non-anabolic or very weakly anabolic for skeletal muscle when taken by itself,
and it definitely not worth the large price if you are taking it solely for
gaining muscle. The only real use in gaining muscle may be as a synergistic
agent with testosterone. A synergistic effect of taking growth hormone with
testosterone has been reported for increases in lean mass, but further research
needs to be done to see if this synergistic effects holds for skeletal muscle.
Keep in mind that some increases in lean mass are not desirable. Growing some organs
too big such as kidneys can produce some embarrassing effects seen in some
professional bodybuilders. You do not want your “guts” sticking
blatantly out of your body.

But enough on growth hormone for muscle gain. For information, see Bryan
Haycock’s article in this issue or go to Michael Mooney’s web site. If you are
going to spend the money on growth hormone to try to improve your body, your
best bet is to use it as a fat loss or “sculpting” agent. The
previously mentioned study with growth hormone on trained athletes did show an
impressive 12% decrease in bodyfat. So well it is well established that
testosterone is far, far better for building muscle than growth hormone, is
growth hormone the better choice for fat loss? The research on this issue is mixed,
and there is no easy answer to this question.

One recent study put growth hormone head to head with testosterone and measured
its effects on fat loss. In this study, men on growth hormone lost an average
of 13% of their bodyfat compared to 5.8% in the group taking testosterone.(4)
But before you jump to conclusions, there are a couple of reasons why this
study doesn’t settle the question. For one thing, this study was on very old
individuals (aged 65 to 8) who had low IGF-1 and testosterone levels. Another
problem is that the doses of the hormones haven’t been reported yet (the study
is only in abstract form right now) which also makes the comparison difficult
to make. Most interesting about this study was that a synergistic effect was
found in a group taking both testosterone and growth hormone, as they lost an
average of 21% of their bodyfat. This is more than the averages of the
testosterone alone and growth hormone alone groups combined.

Not all studies have shown this dramatic of an effect on body fat. One study
using fairly large doses (adjusted by weight, but roughly 5 mg per day) on
obese women failed to show any significant effects on body fat.(5) The growth
hormone group lost less than two pounds more than the placebo group over a one
month period. The main significant result was that the growth hormone group
lost much less lean mass (an average loss of 1.52 kg compared to 3.79 in the
placebo). While this may seem impressive, the same results could be achieved
with a caffeine/ephedrine formula at a fraction of the price. While there are a
good number of studies showing growth hormone to be effective for fat loss,
testosterone may be almost as good for this purpose.

Testosterone was recently found to be effective for fat loss in young men even in
small doses. One recent study showed that men given only 100 milligrams per
week of testosterone enanthate lost an average of six percent of their bodyfat
after eight weeks.(6) 100 mg per week is generally considered a very low dose
by bodybuilding standards. Most impressive about this study was that the result
was obtained in young, normal healthy men (aged 18 to 45), not obese or
testosterone deficient. Most of the studies showing positive effects with
hormone replacement therapy are on subjects who are obese or hormone deficient
– i.e. the very subjects most likely to respond. While the amount of muscle
gain reported in this study was not reported (it is still just in abstract
form), another study showed 100 mg per week of testosterone enanthate was not
anabolic.(7) It appears that testosterone has a strong mechanism for fat loss
other than increased metabolic rate from increased muscle. Considering how much
cheaper testosterone is than growth hormone, it may well be the cost-effective
choice for burning fat even if it is slightly less effective overall.

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Safety of Growth Hormone and Testosterone

Testosterone is widely believed to be far more dangerous than growth hormone. However,
recent research is rapidly showing that much of these dangers have been
exaggerated. For instance, the hypothesis that testosterone causes prostate
cancer has never been established. In fact, one study even showed a slight
negative correlation between testosterone levels and prostate cancer! A study
on young men given supraphysiologic doses of testosterone showed no change is
prostate specific antigen (PSA), which is one measure of prostate cancer
risk.(8)

Growth hormone may also be less dangerous to the prostate than previously
believed. One study showed strong positive correlation with prostate cancer and
IGF-1 levels.(9) Since growth hormone stimulates IGF-1 synthesis in the liver,
this study and others bring up the possibility of a link of growth hormone and
prostate and breast cancer. Keep in mind that statistical correlations do not
necessarily prove causality, i.e. IGF-1 has not yet been proven to be a
cancer-causing villain. Actually IGF-11 may be one of the culprits in the
cancer story, and not IGF-1. At the Serano sponsored Symposia on the
Endocrinology of Aging in October, 1999 and at the Endocrine Society Meeting in
June, 1999 there was an informal consensus that patients on growth hormone did
not increase their risk of breast or prostate cancer. Several other recent
studies have also cast doubt on the role of growth hormone as a cancer-causing
villain.

Testosterone may have also gotten a bad rap for its effects on blood lipids.
Since testosterone and other anabolic steroids have been shown in some studies
to lower HDL cholesterol levels, it was believed that testosterone may increase
the risk for heart disease. This was refuted in one recent study on
testosterone that showed some positive results. A study on 21 hypogonadal men
(aged 36 to 57) showed a replacement dose of testosterone using the Androderm
transdermal patch to reduce blood clotting.(9) While HDL levels did drop
slightly, blood coagulability is believed to be the more important marker of
heart disease risk. Another study showed a very strong negative correlation
with testosterone levels and heart disease.

Growth hormone has shown mixed results on its effects on heart disease risk.
One study on elderly men and women (aged 65-88) showed that growth hormone
administration to lower LDL levels, but raised triglyceride levels.(10) Since
high LDL and triglyceride levels are considered measures of heart disease risk,
growth hormone’s effects on heart disease risk are ambiguous. However,
long-term use of growth hormone as been shown to decrease the thickness of the
carotid artery lining – i.e. increased room for blood flow.

While much more research needs to be done, I am convinced right now that
testosterone replacement therapy in hypogonadal men may be safer than
excessively large doses of growth hormone. The long-term studies have not yet
been done to test the true long-term effects of these hormones, but the
research seems quite clear at the moment. Michael Mooney has reported similar
results on safety and side effects of these hormones:

While none of the studies on testosterone or anabolic steroids used for HIV
have documented any significant health problems associated with their proper
therapeutic use, Dr. Gabe Torres’ data on his patients who experienced a
reduction in symptoms of HIV-related lipodystrophy with Serostim growth hormone
showed that at the standard 5 and 6 mg doses, 80 percent of his HIV patients
experienced significant side effects, that included elevated glucose, elevated
pancreatic enzymes, or carpal tunnel syndrome. (1)

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Conclusion

Don’t get me wrong – I still use both growth hormone and testosterone as part
of overall anti-aging programs in my patients. This article is not meant to say
one hormone is “good” and another is “bad”. It is just my
opinion at the moment that the overall benefit/cost ratio for improving body
composition is higher with testosterone than growth hormone. By cost, I mean
both the monetary price – testosterone is far cheaper than growth hormone, and
the side effect/safety profile – testosterone is safer than high-dose growth
hormone use.

Since growth hormone is extremely expensive and perhaps riskier than
testosterone, I screen patients very carefully and only recommend it to those
who either have very low IGF-1 levels and fail growth hormone stimulation
tests, or those who have failed to respond to testosterone or other therapies.
The new research has also made me confident in encouraging more and more
patients to go on testosterone. However, we must keep constant track of the new
research to better refine both anti-aging and bodybuilding programs. The
science of hormone supplementation is still in its infancy, and there is still
a lot more questions that need to be answered.

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References

1. Mooney, Michael, HIV Study Shows No Muscle Growth From Serostim Growth
Hormone, Medibolics, July, 1999

2. Yarasheski KE; Campbell JA; Smith K; Rennie MJ; Holloszy JO; Bier DM. Am J
Physiol Effect of growth hormone and resistance exercise on muscle growth in
young men. Am J Physiol, 262(3 Pt 1):E261-7 1992 Mar

3. Crist DM, et al. Body composition response to exogenous GH during training
in highly conditioned adults. J Appl Physiol. 1988 Aug;65(2):579-84.

4. Blackman, MR, et al. Effects of growth hormone and/or sex steroid
administration on body composition in healthy elderly women and men, Presented
at 1999 Endrocrine Society conference, San Diego, California

5. Tagliaferri M, et al. Metabolic effects of biosynthetic growth hormone
treatment in severely energy-restricted obese women. Int J Obes Relat Metab
Disord. 1998 Sep;22(9):836-41.

6. Anawalt, BD, et al. Testosterone administration to normal men decreases
truncal and total body fat . Presented at 1999 Endrocrine Society conference,
San Diego, California

7. Friedl KE, et al. Comparison of the effects of high dose testosterone and
19-nortestosterone to a replacement dose of testosterone on strength and body
composition in normal men. J Steroid Biochem Mol Biol. 1991;40(4-6):607-12

8. Cooper, C.S., MacIndoe, J.H., Perry, P.J., Yates, W.R. and Williams, R.D.:
The effect of exogenous testosterone on total and free prostate specific
antigen levels in healthy young men. J Urol, 156:438, 1996.

9. Wallace, J., et. al (1998) Growth Hormone and IGF Res (abstract) 8(4): 329,
348

10. Christmas, C. et al, Effects of growth hormone and/or sex steroid
administration on serum lipid profiles in healthy elderly women and men,
Presented at 1999 Endrocrine Society conference, San Diego, California


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