|GHRH analogues like tesamorelin trigger the release of growth hormone.|
Outside of studies in patients with frank GH deficiency (GHD), there is yet relatively little "non-broscientific" N=1 evidence of the effects of growth hormone administration or the use of agents like tesamorelin, which act like the hormone that triggers the release of growth hormone, on the amount and structure of body fat. And guess what!? In the obese these agents work like a charm and are considered a safer alternative to regular growth hormone injections.
In the obese, GH plays an intriguing role in the development and maintenance of superfluous body fat. As you can see in Figure 1, there is a self-reinforcing cycle of increased visceral fat and reduced GH in states of abdominal obesity.
|Figure 1: Self-reinforcing cycle of increased visceral fat and reduced GH in states of abdominal obesity (Stanley. 2014).|
How valuable are natural growth hormone boosters: If you are into GH peaks on graphs in papers, they are very valuable. If you are looking for real-world results, though, they are useless. GABA for example will transiently spike your growth hormone levels but ameliorate the response to natural triggers like the exercise induced decrease in blood glucose (Cavagnini. 1980). GH boosters will also flatten the natural diurnal peaks. Accordingly, the area under the curve, i.e. the total amount of GH your body produces, will be more or less identical. This is why GABA, one of the most potent, and arginine or lysine, two other often advertised natural GH boosters, are unlikely to have significant effects on your physique - muscle- and fat-wise.
|Figure 2: Percent changes in visceral and saturated fat in HIV infected subjects after tesamorelin treatmend (Stanley. 2014).|
Unfortunately, the results in Figure 2 indicate that the effect was reversed in those subject who got a placebo instead of tesamorelin in the 2nd phase of the 2x 26 week study.
Is GH dangerous? Well, in the studies cited here there benefits prevailed. In the study by Nam et al. for example, the researchers observed not just reductions in body fat, but also significant increases in glucose disposal rate compared to the exercise + diet alone group. The same goes for the serum glucose levels and insulin- and FFA-area under the curve during an oral glucocse tolerance test, as well as the long-term blood glucose measure HbA1c and LDL levelswhich were all signifcantly decreased after GH treatment. This does not exclude, though, that GH can entail unwanted side effects like joint pain and peripheral edema, which are yet rarely seen in scientific studies, unless the hormone is administered in excess.GH works in "normal" overweight individuals, as well, but scientists are still hesitant to test it, probably because this may entail an increase in the already huge interest in GH treatment for lifestyle purposes.
|Figure 3: Effects of 12-week treatment with 0.15 IU/kg body weight growth hormone per week or exercise + 25kcal/kg body weight diet alone in a 18 newly diagnosed obese type 2 diabetic patients (Nam. 2001).|
- Cavagnini, F., et al. "Effect of acute and repeated administration of gamma aminobutyric acid (GABA) on growth hormone and prolactin secretion in man." Acta endocrinologica 93.2 (1980): 149-154.
- Nam, S. Y., et al. "Low-dose growth hormone treatment combined with diet restriction decreases insulin resistance by reducing visceral fat and increasing muscle mass in obese type 2 diabetic patients." International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity 25.8 (2001): 1101-1107.
- Stanley, Takara L., and Steven K. Grinspoon. "Effects of Growth Hormone Releasing Hormone on Visceral Fat, Metabolic and Cardiovascular Indices in Human Studies." Growth Hormone & IGF Research (2014).