Diet is key. It's 98% of the battle, even more so than what you do in the gym. Working out just creates the environment/potential to bulk or lean out. Quantity and type of calories, depending on training program, i.e. more protein, healthy fats and carbs. It's a science and it comes down to food. Supplements can assist that environment if the right stimulus is provided. I don't believe there is any one supplement that on it's own will burn a "measurable" amount of fat, but if you take that supplement and introduce it into the right environment, for example a fasted cardio session, then you begin to see results. I use bulk cissus, bcaas (pre,intra,post for fasted cardio sessions), alpha-t2 with a stim based product of my choice (for now white lightening from APS), Erase for cortisol control and 10-12 grams of fish oil combined with 5 grams of CLA a day.