Human growth hormone is considered one of the three major anabolic
hormones in the body, with the other two being testosterone and insulin.
GH is of special interest to bodybuilders and athletes for
several
reasons.
The first is its reputed anabolic property. GH aids in nitrogen
retention and also helps to transport animo acids into muscle for use in
muscle protein synthesis.GH has also engendered a reputation for
speeding bodyfat loss, since it promotes the sparing of carbohydrates,
while at the same time fostering the use of stored fat as an energy
source.
Over the years it has become apparent that GH is not as anabolic in
actual practice as it appears to be on paper. In fact, most studies
suggest that GH doesn’t offer any anabolic benefits to healthy young
athletes who are still able to secrete GH at a normal rate. Conversely,
GH production drops by 15 percent for each decade of life past age 30,
and many older people show unmistakable GH deficiencies. When they’re
given supplemental GH injections, they respond by making definite gains
in muscle mass, along with a significant reduction in bodyfat stores.
The fact that GH may not be as anabolic in younger people as was
originally thought hasn’t lowered its popularity among athletes and
bodybuilders, many of whom have added insulin to their anabolic
regimens. While the primary purpose of insulin is to treat diabetes, it
also has some anabolic effects. In relation to muscle, it exerts mainly a
permissive effect in that it prevents excessive muscle breakdown while
promoting amino acid uptake into muscle. Some studies show that insulin
can convert from being mainly anticatabolic in muscle to anabolic if a
large amount of amino acids are also present.
Bodybuilders use insulin because it appears to be synergistic when
combined with anabolic steroids and GH. A major side effect of GH is
hyperglycemia, or elevated blood glucose. It’s tempered by simultaneous
use of insulin, which also adds to the GH’s anticatabolic effect.
Let’s face it: Using drug forms of insulin and GH, as well as
anabolic steroids, is not without risk. One obvious effect of this drug
triumvirate is an enlarged, or bloated, abdomen. In recent years the odd
appearance of some professional bodybuilders, who display both deep
abdominal muscle definition and, when they’re not flexed, bloated
abdomens, has been blamed on the combination of insulin and GH. Many
other side effects are possible, depending how much and how long the
drugs are used.
Natural bodybuilders, in their efforts to add muscle and lose
bodyfat, look for ways to boost their various anabolic hormones without
taking drugs. The most potent nutrients known to boost GH are amino
acids, with arginine and ornithine leading the way, although several
others can also do it to a lesser degree. Testing of the branched-chain
amino acids showed that leucine and valine boosted GH by 10 percent, but
the third BCAA, isoleucine, had no effect.
The idea of using arginine as a GH-booster is controversial, since
most studies show that the usual oral dose for that purpose is not
effective. Arginine
is effective when administered
intravenously—at doses of 30 grams. In fact, that route is so effective,
it’s often used as a test to determine whether patients are deficient
in GH. Giving intravenous arginine leads to an average 800 to 2,200
percent increase in GH above baseline, or resting, levels.
The I.V. route works because of not only the greater arginine uptake
but also the insulin that’s secreted due to the presence of that much
arginine. The lowered blood glucose that results leads to the GH
release, as GH opposes low blood glucose. Attempting to take 30 grams of
arginine orally would lead to rapid nausea and likely vomiting.
Arginase enzymes located in the liver and intestine would degrade most
of the ingested high-dose arginine, so you would be left nauseated but
without a significant GH release.
Ornithine is a metabolite of arginine that plays a major role in
helping the body produce urea, the major nitrogen waste product of
protein metabolism. That’s an important function, since without
significant urea production, ammonia would build up in the body, leading
to toxic consequences. Ornithine is said to be about twice as effective
as arginine in stimulating a GH release, although that isn’t saying
much when you consider that oral arginine is not too effective for that
purpose. As with arginine, the studies that have examined ornithine’s
GH-releasing effects have shown mixed results. One study did turn up a
significant GH effect from ornithine with an oral dose of 170 milligrams
per kilogram of bodyweight, but the dose led to gastrointestinal
distress in more than half of the subjects. Both arginine and ornithine
taste awful, so that may have played a role.
Some have suggested that experienced bodybuilders who train intensely
have already reached their maximum GH release, so using a supplement
purported to boost it would be like trying to add more water to a glass
filled with water. A recent study seemed to confirm that.
1
Ten young men, average age 22, who had never lifted weights got either
0.1 grams of ornithine per kilogram of bodyweight or a placebo. Their
blood was drawn and tested for GH both before and after they performed
biceps curls using a weight equal to 60 percent of maximum, which is
fairly light.
Although ornithine is said to peak in the blood within an hour, the
subjects in this study had high blood levels—500 percent above
baseline-—two hours after they took it. Those using the ornithine also
had GH levels that were 200 percent higher than the placebo group 30
minutes after exercise. Again, however, most published studies of
experienced trainees show little or no response from oral
supplementation with amino acids, unless they’re taking large doses,
which often leads to extreme nausea. It may be similar to what occurs
with other supplements, such as HMB, amino acids like ornithine and
arginine—it may work more effectively for beginners than advanced
trainees.
Another recent study examined whether other nutrients besides aminos can affect GH release.
2
It featured a two-part design. The first involved 108 men and women,
while the second used 12 men. Both groups initially were tested to
determine basal, or resting, GH, as well as body responses. The ages of
the subjects in the first part ranged from 18 to 55, while those in the
second part ranged from 18 to 60.
Part one found several nutrient associations with GH release,
including vitamin C, dietary fiber and two saturated fatty acids. All
appeared to promote GH release. Substances that blocked GH included
dietary cholesterol and trans fats. Vitamins D and E and omega-3 fatty
acids were not associated with peak GH release. All other carbs, amino
acids and fatty acids were also not linked to GH release. Low levels of
insulinlike growth factor 1, which is a product of GH, were linked to
age and bodyfat but higher levels were associated with dietary fiber
intake. No other nutrients were shown to affect IGF-1, although higher
levels are associated with protein intake.
In the second part of the study that featured 12 men, one type of
saturated fatty acid decreased the amount of time GH existed in the
blood while another seemed to interfere with nighttime release of GH,
which normally peaks at night. The one nutrient that showed the greatest
relationship to GH release was vitamin C. The question is why.
Vitamin C is well-known as an antioxidant, but it also works with
various enzymes in the body. One example is that vitamin C is required
as a co-factor for enzymes that synthesize L-carnitine from amino acids
in the body. Vitamin C also plays an important role in the production of
collagen, a primary protein in connective tissue. In relation to GH,
vitamin C acts as a co-factor in the activity of an enzyme called
peptidylglycine alpha-amidating monooxygenase, or PAM, which activates
various neuropeptides, or brain proteins.
It turns out that PAM exists in great amounts in both the
hypothalamus of the brain, where growth-hormone-releasing hormone is
produced, and the pituitary gland, where GH is produced. The thought is
that vitamin C, through its actions on PAM, activates
growth-hormone-releasing hormone from the hypothalamus, which then
triggers the release of GH from the pituitary gland.
So should you take in massive doses of vitamin C to promote GH
release? That would not be feasible, since blood levels of C peak after
an oral dose of only 200 milligrams. Although the Recommended Dietary
Allowance of vitamin C is 75 milligrams a day for women and 90
milligrams for men, in this study 44 percent of the 108 part-one
subjects did not meet even those levels. The thing to keep in mind about
these findings regarding vitamin C and GH release is that it optimizes
normal release of GH.
Editor’s note: Jerry Brainum has been an exercise and
nutrition researcher and journalist for more than 35 years. He’s worked
with pro bodybuilders as well as many Olympic and professional athletes.
To get his new e-book,
Natural Anabolics—Nutrients, Compounds and Supplements That Can Accelerate Muscle Growth Without Drugs, visit www.JerryBrainum.com.
IM
1 Demura, S., et al. (2010). The effect of L-ornithine
hydrochloride ingestion on human growth hormone secretion after strength
training.
Adv Biosci Biotechno.1:7-11.
2 Denny-Brown, S., et al. (2012). The association of macro and micronutrient intake with growth hormone secretion.
Growth Hormone and IGF Res. 22(3-4):102-7
©,2015 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited
Have you been ripped off by supplement makers whose products don’t
work as advertised? Want to know the truth about them? Check out Jerry Brainum's book Natural Anabolics, available at JerryBrainum.com.
The Applied Ergogenics blog is a collection of articles written and
published by Jerry Brainum over the past 20 years. These articles have appeared
in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the
blog are original articles, having appeared here for the first time. For Jerry’s
most recent articles, which are far more in depth than anything that appears on
this blog site, please subscribe to his Applied Metabolics Newsletter, at www.appliedmetabolics.com. This
newsletter, which is more correctly referred to as a monthly e-book, since its
average length is 35 to 40 pages, contains the latest findings about nutrition,
exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and
other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of
writing and intense study of all matters pertaining to fitness,health,
bodybuilding, and disease prevention.
Want more evidence-based information on
exercise science, nutrition and food supplements, ergogenic aids, and
anti-aging research? Check out Applied Metabolics Newsletter at www.appliedmetabolics.com
Please share this article with your friends on facebook
