Really what it does is to help preserve muscle mass while you're losing weight. As you diet, that stresses your body and makes you spit out cortisol. Cortisol makes your body break down muscle tissue for energy and store as much as fat as possible in order to adapt to an environment where food is scarce.
11-KT reduces your body's ability to produce cortisol and has some anabolic properties. This blocks your body's ability to break down muscle for energy. So, if you're in a calorie deficit/energy deficit and you can't make it up by breaking down muscle, your body has no place to go to make up that energy deficit other than fat cells.
The thing is, you have to do the dieting and exercise still. To say 11-KT "burns fat" is not really true. Just using it without restricting calories won't "burn fat."