Thats the million dollar question! People with knowledge sometimes have a hard time even figuring them out! the issue is they dont want to you know what your taking... look at this.

Hydroxycut Ingredient Research - Details on the Various Studies Conducted on Key Ingredients in Hydroxycut

never says an ingredient list!! but lists (Garcinia cambogia extract, Gymnema sylvestre extract, and chromium polynicotinate) these three their purpose, crub hunger and controls blood sugar BUT I would still same the MAIN ingredients are caffine and something that mimics ephedra. But you would never know it from their "independant peer reviewed research" ie... those guys we paid! they do have the full list on a pop out on another page...but the problem is that you have no idea how much of an one substance you are taking! They brake it down into two sections a 1.32 gram of four things and a 414 mg of four items. It appears the first is to curb appetite and the second is about 200mgs of caffeine from different sources! Ill have to go look up No-xplode. I should point out too that the reason I have to look this stuff up is they are constantly changing the list! adds to the confusion!