New Study Shows GH Better at Burning Fat
Numerous articles have appeared in this magazine extolling the benefits of human growth hormone (hGH) for increasing muscle mass and decreasing body fat. Professional and amateur bodybuilders are known to use hGH to increase and enhance muscularity. In fact, hGH has become one of the more prevalent drugs used by the upper echelon of the iron sports.

Despite the known effects of hGH on the fat cell1,2 and the results that are being reported by anti-aging practitioners and bodybuilding enthusiasts, most physicians have remained unconvinced of the body-altering properties of hGH. After all, few randomized, placebo-controlled studies have been published. Recently, however, a study was published in one of the flagship journals of medical literature, the Journal of the American Medical Association (JAMA).3 The study in JAMA compared the effects of hGH and testosterone on muscular strength and body composition in mature men. It also documented the efficacy of hGH, either alone or in combination with testosterone enanthate, in improving body composition. However, the design and implications of this study need to be understood before attempting to use the results in support of hGH for bodybuilding or related uses.

 Marginal Benefits?
The JAMA  study looked at elderly men, 65 to 88 years old, who were already low in natural levels of both testosterone and hGH. These men were divided into four groups, receiving either hGH, testosterone, both drugs, or a placebo (chemicals that have no effect). These men were then examined weekly to look for signs of side effects. If side effects arose, drug doses were lowered. At various points throughout the study, measures of muscular strength and body composition were gauged.

The JAMA  study showed, relative to body composition, that the elderly men benefited marginally from testosterone enanthate; hGH either alone or in combination with testosterone provided significantly greater benefits, with increased lean body mass (LBM) and reduced body fat. These results could have been anticipated, based upon previous studies and field use by athletes and anti-aging practitioners. Seemingly, this study contributes little to the use of hGH for fat reduction other than confirming its already acknowledged actions. But, actually, within the report there are a number of valuable insights.

Despite the fact that the group chosen (elderly men 65 to 88) received low doses of hGH (approximately 1.5 to 2 mg (4 to 6 IU) hGH three times per week), a positive change was detected, with subjects gaining three to four kilograms of lean body mass (LBM) and losing about the same over six months. This is particularly impressive considering that absolutely no dietary or exercise recommendations or changes occurred with the drug treatment. Further, in the group receiving both hGH and testosterone enanthate (100 mg every two weeks), improvements in physical performance were seen. The group receiving both drugs demonstrated improvements in strength and VO2 max (a measure of cardiovascular endurance) that would normally only be seen after six months of exercise. These results are very promising for the elderly. It is important to note that hGH therapy alone did not increase strength in this study, an observation noted by many bodybuilders, even when using supraphysiologic doses.

This information may incite a mad rush of bodybuilders getting fake IDs from Grandpa, or convince them to become best friends with the local nursing home, but if it does, the point has not been made clear. The men in the study were already suffering from a low output of natural hGH and testosterone and the drugs provided were dosed to replace normal values seen in 30-year-olds. However, the study still revealed some information worthy of note.

Hormone Therapy at Issue
Body composition is sensitive to changes in hGH production and release.4-6 Since hGH is released in pulses from the pituitary, a product that represents the long term status of hGH is used for measurement, a secondary hormone called Insulin-like Growth Factor-1 (IGF-1). IGF-1 is created by skeletal muscle, liver and other tissues in response to hGH stimulation and is responsible for many of the anabolic effects. As this study revealed, when IGF-1 is reduced, whether through age or disease, LBM is lost and fat gain begins. Many athletes, particularly competitive athletes, suffer from hormonal imbalances when they are overtrained.7,8 So, is it possible that athletes may benefit from hormonal therapy, replacing the hormone production that is lost when the body is exposed to long-term stress?

The study clearly demonstrated that body composition is closely related to hGH, and referenced other studies confirming this relationship. Overtraining syndrome is common in competitive athletes and is even seen in recreational athletes to a lesser extent. One aspect of overtraining is an interruption in normal hormone balance, with an increase in catabolic hormones (e.g., cortisol) and a decrease in anabolic hormones (i.e. testosterone, growth hormone).7,8 Currently, there is no accepted protocol for hormonal support of athletes; in fact, there are severe restrictions and sanctions against providing hormones to athletes, both for the athlete and the physician. However, if one considers the effects of overtraining as a treatable condition, there is scientific rationale behind the use of hormonal support.

Perhaps the next era of sports medicine will look at hormone replacement therapy for athletes, though it would require a complete turn-around in mentality and "ethics" from the sports organizations, players unions and state and federal lawmakers. Most likely, such use would only be allowed in military applications, to improve the performance of soldiers in the field or in recovering from a mission.

Hormonal use by athletes is considered "doping" as the levels used by most athletes are far in excess of "normal" levels and are often so high as to cause harmful side effects.9 The JAMA study was valuable in that it documented adverse side effects from the admittedly low doses of hGH and testosterone enanthate. Even in this group of older men, who would be considered to be at higher risk for certain cancers, no malignant side effects were noted as a consequence of six months of low dose hGH therapy. In addition, maintaining IGF-1 levels within a moderate range reduced the risk of hGH-related side effects.3 Even with the reasonable doses used, however, there were a number of side effects reported with hGH therapy, consistent with other reports in the literature, such as diabetes, carpal tunnel syndrome, joint pain and gynecomastia. Fortunately, the diabetes, carpal tunnel syndrome and joint pains seemed to be relieved over time with a lowering of the dose; there was no clear indication as to whether the gynecomastia required further treatment.

Study Limitations Explored
This study concluded with the call for further research and was correct in doing so, as there are other interventions that could have further benefited the subjects. The weekly dose was in a range felt to benefit fat reduction (12-18 units/week), but it was not administered in the most appropriate schedule. Rather than injecting the hGH three times per week in higher doses, the subjects may have responded better, with fewer side effects, using a twice daily injection schedule, as is commonly recommended.

Also, the dose of testosterone enanthate was well under what is commonly provided for hormone replacement and the half-life of testosterone enanthate is too short to allow for consistent levels over 14 day periods.10 Bodybuilders commonly use 200-800 milligrams of testosterone enanthate every week, injecting the drug once per week to maintain elevated levels.10 The use of a longer chain ester or more frequent injections, as well as a higher testosterone dose, may have provided more valuable data.