I used this product after having my first baby 9 months ago.  I wasn't that concerend with making my hips narrower, but i wanted to help provide some compression to aid healing since I had terrible hip pain due to the normal loosening of the ligaments and joints during pregnancy.  I also had a sepatated pelvis due to giving birth. I wore it as per the instructions, but I found that to wear it tight enough to feel supported, it cut into me enough to really cut off my circulation.  I was average sized when i first had my baby, around a size 8 or so, so i don't think it was a matter of it being too small.  I ordered the appropriate size.  It was very uncomfortable and too narrow in my opinion.  It flattens your butt too when it's on.  No way to wear this under you clothes in public.  I wore it for 6 weeks as often as I could and i still have weak/painful hips and my pelvis only healed a few weeks ago (or stopped hurting anyway, lol).  I never measured anything so i don't know if it actually shrunk my hips.  I had also bought the belly flattening wrap (the ones promoted by Kourtney Kardashian I think) and it was great.  Stiff, but it needed to be.  (Worked great btw.  With the wrap and breast feeding my belly was gone in like 2 weeks.) I actually wore that around my hips sometimes for the pains and it was much better that the shrinkx hips belt.