As an engineer or just using common sense, it seems to me that even if a garment held scent in from underneath, it would still have to be scentless itself. In otherwords, you may be holding in your body odor, but your scent-lok is still going to smell like your closet or your pickup or whatever the outerlayer has been exposed to.

Most people I know don't use anything except maybe some spray on stuff. I keep all my hunting clothes in tupperware with cedar shavings and pine needles, and I put on my top two layers after I get out of the truck and I am standing in the woods. If you do that and keep the wind in mind, you should to pretty good.