IMO they do help to a certain degree, but you still have to take care of the exterior. The interior layers will absorb some human body odors but if you wear them into the 7-11 on the way to your stand they will do you no good. I wash all of my layers in scent free soap and keep them in a scent free air tight bag and ONLY wear my outer layers (Which are not scent lock products) when in the field. I completely change clothes at the truck before entering the field and when I get back to the truck I store them again. I believe this helps more than scent absorbing products. I do believe a scentlock facemask and head cover is most important as I tend to sweat from my head just walking to my stands. I do still play the wind and will never hunt a stand that I expect deer to come from downwind. I don't believe that much in any product. Out west where I have to do way more walking and sweating, I don't think they will help that much. just 2 cents from a Midwest bowhunter.
Its come up before, it has zero utility for western hunting but I think it has some value as midwestern bowhunter when you aren't talking about much exertion if you have fixed stands (it all goes out the window if you have to pack you stand in and out on public).
I use it because I already own it and am fairly skeptical but here are my thoughts on the issue. I have had less snorting and getting winded using the stuff. I remember it made a difference just using UV/scent free detergent and bumping into deer while turkey hunting before we had any of the carbon clothing. The days I get busted now are the second day of a hunt when we didn't wash clothes after helping drag out a deer, not the days I forgot to spray my backpack and boots.
A lot of very good successful eastern bowhunters are very much scent control fanatics (not sponsored guys), I'm not sure that its the scent control as much as the way they apply their OCD habits to diligent hunting. Basically they guy who is OCD about scent control is also OCD about his stand placement and wind directions.
Besides getting winded I feel scent control might help lessen the degree to how recently a deer thought you were in the area when it crosses your path and lessens pressure impacts which is a huge thing in high pressure areas.I personally don't see myself buying more, but I will use the stuff I have now, it can't hurt.
Brushing it off as pure snake oil because it isn't relevant to how or where you hunt isn't really a good argument. Its a class of products with at least 3 different scientific concepts: carbon filtering, ozone filtering and scent confusion and each really stands on their own as to why they would be discredited.
There was a class action lawsuit when they advertised it as "forget the wind, just hunt". That's a pretty bold statement which is why they got in trouble, not that it doesn't have value. It also only applies to one of the classes of products out there.
You can hunt the wind just fine if you are spot and stalking an animal or even working in on bugling elk to a certain degree. But plop your stinky butt down in the Midwest whitetail woods where deer can and do come from all directions to you, not you to them, and then tell me that none of it matters. You won't shoot much. Don't bash what you don't know and haven't done. I'm not saying you can just put brand X clothes on and go sit in any tree and expect deer to walk in from downwind. But, if you are willing to invest a pile of time, energy, and money into your sport why wouldn't you do one simple thing to up your odds? If deer get nervous down wind of me that's ok, I expect that, but if I flat out stink and they snort and blow and raise hell because something is in their living room that doesn't belong there, that's a bad deal, and it still happens from time to time. I'd rather have them just get a little nervous and move on. Like was said above, you still have to be OCD about your clothing fabric exterior or the carbon this or silver that won't make a difference.