I have no idea what's happening here. I've worn size medium underwear since I can remember. Every brand. Every time. Except this time. The size medium felt like they were way too small. Super low rise. Awkwardly short. Too tight. It's like they put a medium label on a small or XS set of boxer briefs.
Luckily I have a skinny 11 year old son, and the size medium fits him. By the way he's 5'3" and 100 lbs. So strange.
But moving on from the size, this set of boxers is like 3X more expensive than the Gap set I also got from Sams, and the Gap set feels nicer to me. This set from Saxx is all super light mesh. Maybe if you're looking for a workout pair or something, but wearing this light, super thin nylon mesh all day seems a little strange to me. They weren't comfortable. The waist band does seem higher quality than your typical $5 pair of boxer briefs. If you're looking for a thin, ultra light, nylon mesh boxer then maybe try these, buy a size up for sure though. But gosh, even then they should have had more elastane built in to the mesh to make it more comfortable, stretchy, etc. These just seemed kind of stiff. I had high hopes and left incredibly disappointed.