Well, you know that’s a little thing that is considered more of a choice by some users. Some prefer scented, than unscented. However, I’m sure that they will still be diffusion.
I suggest reading this thread to get a general idea: unscented pheromone effectiveness
Some pheromones supposedly stink, so some say unscented might make these smells noticeable. I have not tried unscented, so I do not know.