Does acai berry detox work?

okay im 15. and i got the acai berry detox. im 179 pounds and i wanna loose a little weight. it says dont take if you under 18 but why not? i wont be taking 2 a day, just 1 a day. i think they dont want kids under 18 to take it because they dont think they need a dietary supplement. but i tryed everything to loose a couple pounds and nothing is helping. so i wanted to see if this works.please tell me if it works. thx