I am a 47 year old female & bought these boxers for myself. I ordered XLarge when I normally take a medium or large, and they are very restricting across the butt. Plenty of comfort in the waist elastic, but no room in the butt. I would go up to a XXXLarge if I buy these again, & take the chances of possibly having to take in the waist with my sewing machine. The thinness of the fabric is fine, it's not thick at all, but not too too thin. I won't buy them gain, though, because they aren't proportionate to real bodies with actual sizes & shapes. If you have a flat rear end(no butt), you would be just fine to order one size larger than regular.I ordered these for my husband. if you want a fuller boxer look and fit I suggest you buy a size (or 2) up. The length is much shorter than regular boxers. my husband likes them and they meet his needs for lounging around the house. I would recommend these if anyone asked me. :)Returned as the material was not what I thought. The seller should be more detailed of the fabric description.didnt expect the style, yet they fit great and comfortably.price was good, given to homelessExcellent product!I even ordered up a size but these were still too smallThis product was too small for my husband.