Updated: Aug 22, 2021
Your waist trainer should fit tight enough that you are able to pull your waist in on the 3rd hook closure.
It should have enough structure to not roll over the waist (this is a sign the waist shaper is too small).
Your waist trainer should not interfere with your breathing and you should not experience any pain.
The garment is going to feel uncomfortable until you get used to it. This is why you gradually build up to wearing the trainer for longer periods of time.
The shaper should close properly with no bulging.
Always break in your waist trainer for a more comfortable fit.
Measure your natural waist - often the smallest part of your waist. This is the waist measurement you need to check to get the right size for your needs and waist training goals.