You shouldn't even get stopped, and if you do I believe technically it's only illegal to purchase it without a prescription, but it's OK to possess (I'm from Canada so it might be different for you, but I highly doubt you will run into problems). I remember I flew back from California with my 1st NP bulk order, and I had about 10 white tubs labelled of Leucine, Creatine, Cissus etc and the bag-checker gave me a curious look but didn't even worry about it.