5 hour energy isn't sold on property but if you are doing checked luggage you could put some in double zip lock bags and put them in your checked luggage.
I do that sometimes. It always triggers a TSA search though so just a heads up. At least that's what I think triggered it for me. The times I don't bring it, my luggage wasn't searched.
You can also buy them at the airport in the gift shops. I've done that too even if it wasn't a cheap as packing them.
Monster is sold on property but I hate that drink. It tastes nasty to me and I usually feel awful once it wears off.