The data concerning the effects of anabolic/androgenic steroids on insulin sensitivity is difficult to interpret. It does appear that when these drugs are used initially, reductions in body fat are common, particularly visceral adipose tissue. This may actually improve insulin sensitivity and the overall metabolic state, and reduce certain specific risk factors for diabetes and cardiovascular disease. Beyond this, the effects of AAS on glucose metabolism are not fully understood, and difficult to predict. Studies using supratherapeutic doses of testosterone and nandrolone have failed to produce any negative changes, suggesting that moderate AAS abuse is probably not associated with impairments in insulin sensitivity. At the same time, studies do suggest that there could be concerns with heavy steroid abuse. Further research is needed is assess the impact of steroid abuse on metabolic health.
Wlliam Llewellyn (2011) - Anabolics