Many people consider Growth Hormone the Holy Grail of Health and Youthful Living. That's a highly debatable sentiment in my opinion, but I can't argue with the fact that Growth Hormone burns fat and contributes slightly to muscle growth as well. As we age, our Growth Hormone output decreases significantly and this is yet another reason we put on weight so much more easily. In fact, at 40 your body puts out only about half as much Growth Hormone as you did at age 40! At age 80 you'll be down near 5% - ouch! - making it one of most severe hormonal reductions that us guys get to go through during the aging process.
How does Growth Hormone do its magic? As it turns out, it is your double-barreled trusty friend that both spares amino acids (the building blocks of muscle) from being burned as energy and at the same time promotes fat to be used for energy. Sound like a fantasy?
CAUTION: Recent research has cast considerable doubt on Growth Hormone's supposed anti-aging properties. For example, one 2010 study on mice found that using a drug that inhibits growth hormone improved longevity, telomerase, cognition and cancer. In other words, inhibiting Growth Hormone looks to be the true fountain of youth! 
Also, keep in mind that Growth Hormone is still very expensive. And it is relatively easy to increase your Growth Hormone output naturally. Here is how you do it:
1) Sleep. Hopefully, you have read my link on Sleep and, if so, you already know that sleep boost testosterone, neurotransmitters, memory and Growth Hormone. This is one reason that experienced bodybuilders often say that muscle is built more at night on the pillow not during the day at the gym.
2) Intense Exercise. Intense Exercise is the kind of exercise that leaves you sweating and breathing heavily. As it turns out, you can dramatically increase your Growth Hormone output for several hours after exercise if you do it the right way. What is the "right way"? Read this link on Interval Training to find out one way.
3) Creatine. Researchers discovered that Creatine, the well-known and well-studied bodybuilding supplement, increased Growth Hormone output post-consumption even in those who did no exercise.  However, there are a few things to keep in mind about this study: it was extemely small with only 6 young men involved. Three of the men experienced a very significant rise in Growth Hormone but the other three much less so. So this many depend on individual physiology and other factors. Nevertheless, it an intriguing finding.
4) L-Arginine. Large doses, say > 7-9 g/day, of L-Arginine increase Growth Hormone output substantially. However, I recommend extreme caution for large doses (> 3g/day) as discussed in this link on Arginine. Dosages of about 2 g/day should be safe.
5) Glutamine. Studies have shown that ingested glutamine at levels even as low as 2 g/day can increase Growth Hormone output. CAUTION: It is possible that increased ingestion of glutamine could raise body levels of glutamate, which is a neuron-killing Excitoxin. Furthermore, glutamine is used by cancer cells for fuel and so theoretically - and this is strictly theoretical - glutamine could be slightly mutagenic.
6) Insulin. Watch your insulin: insulin is negatively correlated with Growth Hormone.  In other words, the more insulin floating around your system, the less Growth Hormone that you are likely to have. The insulin resistant state, where insulin levels stay perpetually high, of the Metabolic Syndrome is a Growth Hormone squasher as are high glycemic meals. Eating a lot of sugars and starchy carbs that cause your blood sugar and insulin to spike is anti-Growth Hormone. For this reason, be careful to not to eat a high carb meal right before bed because nighttime is primetime for Growth Hormone release. And, please, I urge everyone over the age of about 30 to read this link on the Metabolic Syndrome and find out to defeat insulin resistance.
7) Laughter. It appears Growth Hormone may be very sensitive to humor. In a study dating back to the 80's, subjects had an average 87% increase in Growth Hormone just from anticipating a humorous show.  A little laughter goes a long ways as they say.
8) Visceral Fat. Visceral fat and fasting insulin levels are also associated with decreased growth hormone. 
NEWS FLASH: A study in late 2009 showed that a gherlin-like drug called MK-677 increases Growth Hormone significantly to levels of a "healthy young adult".  The health media is calling it a Fountain of Youth - time will tell. Side effects seem relatively mild.
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