I'd be careful. It's obviously "allowed" but you could be given a hard time. I got through normal security fine but when I was chosen for a random secondary check the lady got to my glutamine powder and didn't know what it was. She did one of those ion scans on it which showed nothing but she was still suspicious and I was taken away for further inspection. I got through with it in the end, but then waiting for me in Toronto was a drug sniffer dog (I guess they had called ahead) who met me at customs and waited with me for my bag so the dog could sniff it before letting me out of the airport. Very nice handler and dog who liked belly rubs. I think she figured the fact that I was being so relaxed with the dog probably meant I didn't have anything illicit!