I’m using repair and protect, and I have no idea whether it’s doing anything. Experienced a much greater impact by cutting out most added sugar from my diet (including in coffee).

On Regenerate NR5, there seems to be skepticism on Reddit. This analysis looks solid:

https://www.reddit.com/r/Dentistry/comments/2afh74/has_anyon...

It suggests they’re using fairly standard ingredients that are present in many toothpastes.

Caveat emptor..