i think the only way these really work if not using them in conjunction with healthy eating and exercise is if you apply a patch over each eye so you cant find the fridge lol! One of my mates was on the nicotene patches and she got that desperate once she tried smoking the patch - dont ask!
I use green tea tablets that help to speed up your metabolism but only use them when I plateau with my exercise, and it gives me a boost again.
Like everything though theirs no overnight quick fix or solution. its fat better to get into a decent eating and exercise routine that use crash methods to lose weight. This is the reason you end up putting weight back on, all yo yo dieting. and the more you do it the harder it gets each time to lose the weight.
I have seen amazing results though with clients (and my mum) who have been allergy tested. My mum went from a size 22 to a 16 in a few months because whilst she was eating healthily she was allergic to a lot of stuff she was eating and therefore this caused her to bloat up and she couldnt lose any weight. Also clients have been diagnosed with an underactice thyroid gland which means that they dont produce enough thyroxine to turn the food they eat into energy and instead stores it as fat.
Its worth getting checked for everything before dieting so you dont lose heart.
Also steady dieting is better than losing weight fast as fat cells store toxins (this is why its recommended dieters drink more water) as your fat cells shrink the toxins are released often making you feel tired, sluggish or ill. I do regular colon cleansing at home which isnt nice but aides weight loss too and helps remove nasty toxins and bugs from your digestive system so it works more efficiently.
The tablets and patches are best used for those weeks when you need a little extra push for when you have plateued with your weight so that you dont get disheartened.
good luck
kate x