The author of “Fire-Up Your Fat Burn,” Dr. Lori Shemek, warns that the side effects associated with certain products can be detrimental to users. Fat burners do not need to be regulated by the FDA, meaning it’s unclear what exactly you’re ingesting and whether or not they will work as advertised. In some instances, fat burners were removed off the shelves because they induced medical conditions such as strokes, high blood pressure, and seizures.