If you are willing to use common sense and listen to your body, then, no, waist training is not dangerous. We suggest the use safe and sane corsetry practices anytime you wear a corset, whether you're a serious waist trainer or you're simply wearing a corset as a complement to your fashion choice. The conversation goes something like this:
"Is your corset causing you pain?"
If the answer is a resounding "YES!", then loosen it or take it off completely! The idea of no pain, no gain does not apply here.
A corset does not have to be uncomfortable to give you a gorgeous hourglass figure. Breaking in a corset, also known as seasoning, is important for the corset, but it's also a chance for your body to get used to wearing it. Slow and steady is the rule of thumb for waist training.