DD,
Phen-free is mild thermogenic. EAS uses Synephrine (Citrus Arantium) which is a milder chemical cousin to ephedrine. It also contains Tyrosine, Yohimbe, St Johns, Cayenne, and 99mg of caffeine to increase your metabolism. In my opinion, I don't think its the most siperior fat burner (not even close) but I have to say that its the safest. I was taking a lot of medication awhile ago and Phenfree was the only product that wouldn't counteract with them. Hope this helps!