I've tried a couple of different options and they all cause a weird (to me) aftertaste. Now if I want a sweeter mead, I use a lower alcohol tolerant yeast and start with a higher brix.
Discussion
I really don’t mind the taste of most nonnutritive sweeteners but that’s why I’m going to open a bottle and rest in a few glasses don’t want to ruin a whole batch!
I put it in when I bottled trying to get a sweeter mead, and then it sat for months as I drank my way through all the different wine and mead I made. It may not have fermented, but *something* happened in there, and I didn't really like the results.
Good luck with the experiments!