How long until I see Corset results?

I have an 18" steel boned corset. I moved down from a 25" corset. I wear it for 1-2 hours a day. How long until I see results? Should I wear it for a longer amount of time? I can only tighten it to 23" I want to get it down to 21"

Sur La Mer2016-06-01T21:53:13Z

Mom wore hers 24/7, for the rest of her life, even when she goes to bed, except when she takes a bath.