hi, i've heard of Zantrex 3, it is a product manufactured and researched in the US, therefore more likely the product is more suitable for westerners. it might not be very effective on asians. and it also contains a high dosage of caffeine, if used abusively might lead to undire consequences. also it is not recommended for pregnant or lactating woman.
may i know if you have tried it? i would welcome you to pm for more info on this. =)