Sweat and the AlienGear IWB Holster, pls share your experience.

[Irving]

You guys don't wear an undershirt when carrying?

EDIT: Not exactly what you asked, and I'm not sure what type of belt loop options Alien Gear offers, but I've found that one velcro and one belt loop to be the best for dealing with multiple issues. The velcro keeps the holster from walking up and down the belt, and the belt loop (in the back) keep the holster from pulling free on a draw (as the velcro tends to weaken over time). Also, only a single solid belt loop is easier to be over looked than two belt loops.