I bought this product mainly to smooth panty lines in a sweater dress.  I figured it wouldn't do much in the "support" department because it was so cheap, and I was right.  There's really no support.  Unfortunately, it doesn't do anything to smooth lines, either.  The body of the garment is also ridiculously long and reaches higher than my bra, which is awkward and uncomfortable.  The legs are an ok length, but are longer than in the photo, so if your dress is shorter than knee-length, you might have a problem with these poking out from your hemline.

I would return this if I hadn't already worn it.  Not recommended.  Spend a little more and get a quality product.