I'm diabetic and will normally split my insulin, needles, syringes and other exciting diabetic paraphernalia between my hand and hold luggage. I try to put more than enough for the trip in each, just in case of one bag getting lost/ stolen/ damaged.

I've always been told there is a risk of the items in the hold luggage freezing, but have never had any issues.

I originally would go out of my way to point out to security staff that it was in my cabin luggage when going through the x-ray, but would always get a very nonchalant response so have stopped bothering. In the last 20 years of travel I don't think it ever really came up on the x-ray, only once at BKK and another at AMS.