No, you can check the bag though
If you buy if AFTER the security check... then it might be ok
Can you take energy powder drink mix
That's a HARD NO! Sorry
You can after you go through TSA
You cannot due to the TSA liquids restriction. You can pack it all in your checked baggage (maybe put it in several ziploc bags or a box/container), but you only have liquids equivalent to what's in a travel toothpaste tube in a carry-on/ personal item. If you buy a sixpack of soda from an airport shop after security, maybe it's possible. But if I were you, I'd want my toothpaste + tooth brush accessible in the flight instead of 3 fl oz of soda ;).
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