OK, testosterone and GH have a direct effect. As testosterone levels rise, GH/IGF-1 levels also rise.
Obesity is associated with reduced testosterone and growth hormone (GH). However, the interrelationship between these axes and their independent contributions to cardiovascular risk is unknown. The objectives of this study were to determine (1) the ...
www.ncbi.nlm.nih.gov
www.endocrine-abstracts.org
We conclude that testosterone enhances the effect of GH to increase IGF-I, but exerts a protein anabolic effect that is independent of GH action.
Now, from my recent experience, TRT levels of testosterone may not have enough on declining GH levels as we age to have much of an effect on the skin. I am 67 and stopped the GH over a year ago and noticed that slowly since then my skin quality went down the hill. It start getting dryer and almost like crepe (wrinkles). I started 4iu of HGH last week and the skin quality seems to have reversed. The dryness has gone back to normal and the wrinkles have gone away completely. Not sure at this point if it is the HGH or the sub-q fluids from the 4iu dose. But there is a much different effect on my skin that just TRT provided. This study points directly to the HGH:
The literature highlights the importance of the GH and IGF systems in normal skin homeostasis, including dermal/epidermal cross-talk. GH activity, sometimes mediated via IGF-I, is primarily evident in the dermis, particularly affecting collagen synthesis. In contrast, IGF action is an important feature of the dermal and epidermal compartments, predominantly enhancing cell proliferation, survival, and migration. The locally expressed IGF binding proteins play significant and complex roles, primarily via modulation of IGF actions.
