Cellucor d4 Extreme is unique among thermogenic weight loss diet pills by virtue of the 'tweaking' engineered into the product. Users report a very nice lift without the crash or jitters. You can thank the addition of passion flower for that. Cellucor d4 extreme also opts out of synephrine to instead use a different ephedra analog, Embelic Myrobalan extract. Users report excellent results and a very smooth effect on alertness and energy.