If you're eating so few calories/day, it doesn't matter what you're taking along side it - you will lose weight. The problem is, how much is fat and how much is muscle? Anything I've ever posted about is with legitimate hCG (injectable). I personally don't trust the
garbage they sell OTC at all, but that's just me. That being said, from what I've heard some users say they experience from SD, you may just be bringing yourself to feeling like garbage if you do this. If running an anabolic compound alongside the hCG to ensure muscle preservation, I'd say go with test. Some have run tren. At the very least, you could run OSTA along with it.
I also strongly disagree with the "eat whatever you want" the first 2 days - I feel it only inflates initially weight to help you think "wow, I'm losing so much weight." If anything, keep a normal diet and/or taper down slightly the first day or two before getting to the 500 cal/day.
Again, though, everything I'm talking about is in reference to actual hCG.