As far as I understand, clen raises your body temperature *some* (this depends on the person, dose, etc.) so that your ability to literally BURN fat is raised
I havent tried it but I wouldn't be so eager to purposely give myself a fever. But it's popular amongst bodybuilders.
Arsenic, if it really is the same as the arsenic that poisoned Napoleon, is way more sinister. So "energy" in your body is ATP -- adenosine tri phosphate -- so aresenic has similar characteristics to phosphorous, and it will replace the phosophorus at a certain stage in this energy making process, making your energy-making capabilities less than half as effective. This means you're body has to work at least twice as hard to stay alive, therefore burning more fat. I presume.
"Hydroxycut" and other products listed as "fat burners" are called "thermogenics" -- meaning that they raise your body temperature.
Stimulant usage also works well for weight loss, which is why a skinny guy looks "coked out." Some people who are prescribed or take adderol
(dextroamphetemine complex) on purpose lose weight because it cuts your appetite so much.
The previous standard in bodybuilding weight loss was what people called ACE -- the combination of aspirin, caffeine and ephedra. That's the route I would take to lose weight, it seems the safest