When will I be able to buy this stuff?
Will it work on cats??
Looks like this research is still at the mouse-abusing stage. Leptin supplements are available but you are on your own as to researching the advisability of usage and dosage.
Battle Axe - if the cat is a lost cause then it’s up to you whether to try leptin. You could try to extrapolate from the mouse dosages given at the link. In any case, good luck with the cat.