insulin sensitivity in MUSCLE cells is a good thing. For bodybuilding, insulin sensitivity in FAT cells is not. A lot of these OTC insulin sensitizers contribute to both, or sometimes just fat cells.
for instance: When I tried using R-ALA as a GDA, I found it easy to gain fat added around my waist.
Some of them are good at lowering BG...just important to pay attention to where it goes.
What's the best GDA in my opinion? Ideally before a meal or soon thereafter, do a few body-weight squats, push ups, pull ups or isometric flexing. Hell, just do what bbers do best and flex in the mirror for a few. This has a substantially under-recognized benefit for nutrient partitioning.