Study: GH Hurts Insulin Sensitivity

Growth Hormone Replacement Therapy Induces Insulin Resistance by Activating the Glucose-Fatty Acid Cycle

The effects of GH replacement therapy on energy metabolism are still uncertain, and long-term benefits of increased muscle mass are thought to outweigh short-term negative metabolic effects.

This study was designed to address this issue by examining both short-term (1 wk) and long-term (6 months) effects of a low-dose (9.6 µg/kg body weight·d) GH replacement therapy or placebo on whole-body glucose and lipid metabolism (oral glucose tolerance test and euglycemic hyperinsulinemic clamp combined with indirect calorimetry and infusion of 3-[3H]glucose) and on muscle composition and muscle enzymes/metabolites, as determined from biopsies obtained at the end of the clamp in 19 GH-deficient adult subjects.

GH therapy resulted in impaired insulin-stimulated glucose uptake at 1 wk (-52%; P = 0.008) and 6 months (-39%; P = 0.008), which correlated with deterioration of glucose tolerance (r = -0.481; P = 0.003). The decrease in glucose uptake was associated with an increase in lipid oxidation at 1 wk (60%; P = 0.008) and 6 months (60%; P = 0.008) and a concomitant decrease in glucose oxidation. The deterioration of glucose metabolism during GH therapy also correlated with the enhanced rate of lipid oxidation (r = -0.508; P = 0.0002). In addition, there was a shift toward more glycolytic type II fibers during GH therapy.

In conclusion, replacement therapy with a low-dose GH in GH-deficient adult subjects is associated with a sustained deterioration of glucose metabolism as a consequence of the lipolytic effect of GH, resulting in enhanced oxidation of lipid substrates. Also, a shift toward more insulin-resistant type II X fibers is seen in muscle. Glucose metabolism should be carefully monitored during long-term GH replacement therapy.


I know this is directly referring to replacement therapy, but is there any reason to believe that this carries over to bodybuilding?

To be honest when i ren it i felt there was too much hype with the HGH. I did indeed think to myself that i might not be metabolizing my sugar properly. I had a hard time feeling pumped and full throughout the 6 months i ren it. If i ate too many carbs, i would turn flabby VERY fast. This was very frustrating. Something was definitely off. To this day i feel like i don’t quite pump my muscles the same way as before.

I vote YES to this Study, but it’s individual dependent.

This has long been known. The effect is transient. For those who are on GH HRT, after a few months, things are back to normal. For those who are using GH short term, short term insulin resistance is not going to be a problem.

The study’s conclusion at 6 months contradicts what I have read elsewhere. Below it is stated that the insulin resistance effect go away after 6 months.

See “Grow Young with HGH”, Dr. Ronald Klatz, paperback, page 114 “Growth Hormone and Insulin”

As for BB doses of GH, you will not find clinical studies. Someone here could get a blood glucose monitor, establish a baseline then track during a GH cycle. It would make sense to control gear and E2 levels and hold those steady. Track diet changes as well.

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