Purchased this for my husband so we wouldn't have to take turns sleeping on the couch anymore. He snores very loud, very heavy, and non-stop. I was skeptical about this device but decided it was worth a try. IT WORKED 100% THE VERY FIRST NIGHT! Not kidding. I was shocked actually. He had no problems falling asleep with the mouthpiece in place. He did say his jaw was a little sore the first few nights but he is adjusting to that the longer he uses it. Also note, he wears a plastic retainer on his upper teeth at night and he did his mold with the retainer in so he could continue using the retainer. No issues. Molded perfectly and he is wearing his retainer with the mouthpiece. 10/10 recommend.