I am a guy that is average build.  not skinny.  I am 5'10 and wear a pants size 34 waist and underwear 34 waist.  I read all the great reviews on this so gave it a try.  Turns out they are too small.  They're tight and you know you're wearing them when wearing with pants.  I compared the waist size by putting them on top of my other underwear.  Not even close.  So i bought a size 36 waist in the same underwear which do fit and are comfortable.  You might want to buy one size bigger.  Just a buyer beware. Don't waste your money.