>>40604925 (OP)>>40604941If you are obese or have a male-pattern fat distribution (beer belly) these won't do anything. If you have a flat tummy already, it will trim a couple inches, which is helpful as the other poster said, but its not transformative.
Corsets have 3 functions, imo, the first is the waistline, but 2 other functions are posture correction and defense against over-eating. Wearing corsets will unconsciously remind you to sit up straight as any slouching pokes into your ribs pretty noticeably. So it helps you sit pretty. Other is eating, you will very quickly realize eating and drinking while corseted is not great idea, and you will consume less. So, consuming less food and drink in public also helps feminine presentation.
Please wear it under your clothing, as over-the-clothes corseting is pretty tacky and just makes you look like a Ren Faire cosplayer.
FINALLY, when looking to buy a corset look for metal hooks rather than plastic. Plastic is cheap and will break, corsets have to withstand a lot of pressure and metal does it.