What FitBitch & W6 said.
Basically clen will make you get major jittery -- personally I feel it works at least as well as ECA (Hydroxycut). The T3 affects your thyroid. People use that combination to get really lean like for a competition -- this is when they are already very lean and trying to get rid of that last bit of bodyfat. ANd when you are already very lean, those sorts of "supplements" are more effective. When you are higher bodyfat & trying to lose weight, they really shouldn't be a "magic pill" replacement for a cleanl, consistent diet.
If you are not eating a clean, consistent diet, changing to one (e.g. w/ 6 meals / day, maybe some carb rotation, good fats), you should see awesome results in a short period -- like start seeing some changes w/in 3 weeks after your body adjusts to the change. Initial weight loss would probably be mostly water weight, but once you get your metabolism adjusted you should really start seeing results.
I'm glad you stopped over here to ask about that stuff before jumping on it because someone suggested it. Knowledge is an awesome thing! And I think what we all find out after checking out all these different ways to lose weight w/ this & that supplement, ultimately there is no quick fix and its all just basic diet & training.
So lets look at the stuff you can easily change w/o introducing "controlled substances" into your body when they arent' needed. What does your current diet & training look like?