I've tried them, but if you have facial hair they don't stick well and come off too easily. Instead, I've been using 3M micropore tape - just the right amount of adhesive, my skin feels fine, and cheap too.
It works well to stop me breathing through my mouth.
I have been doing something like this, every day, for several years now. I started with a more gentle kind of tape that doesn't go over your lips. But after trying different kinds of tape, I just stick a small piece of medical tape over my lips now.
I don't have sleep apnea but had a tendency to breath through my mouth at night. It worked almost immediately for me. And what's more, after my body got used to it, I could have a stuffy nose before sleeping, stick on the tape, and when I lie down, my nose would clear up, like it was conditioned to do that.
Seems really dangerous to block the airway. If you get a runny, bloody, stuffed or otherwise blocked nose, seems like you can suffer some bad outcomes.
I spoke with my ENT about this. I was treating anxiety triggered shortness of breath, and found that nose breathing was able to calm me if I box breathe.
She laughed, and said of course taping your mouth is stupid. Which I assumed, but had a friend of mine suggest it because it "changed his life". It's manosphere stuff.
